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Diffstat (limited to 'contrib/llvm/lib/Analysis/InstructionSimplify.cpp')
| -rw-r--r-- | contrib/llvm/lib/Analysis/InstructionSimplify.cpp | 2946 |
1 files changed, 2946 insertions, 0 deletions
diff --git a/contrib/llvm/lib/Analysis/InstructionSimplify.cpp b/contrib/llvm/lib/Analysis/InstructionSimplify.cpp new file mode 100644 index 0000000..16e7a72 --- /dev/null +++ b/contrib/llvm/lib/Analysis/InstructionSimplify.cpp @@ -0,0 +1,2946 @@ +//===- InstructionSimplify.cpp - Fold instruction operands ----------------===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file implements routines for folding instructions into simpler forms +// that do not require creating new instructions. This does constant folding +// ("add i32 1, 1" -> "2") but can also handle non-constant operands, either +// returning a constant ("and i32 %x, 0" -> "0") or an already existing value +// ("and i32 %x, %x" -> "%x"). All operands are assumed to have already been +// simplified: This is usually true and assuming it simplifies the logic (if +// they have not been simplified then results are correct but maybe suboptimal). +// +//===----------------------------------------------------------------------===// + +#define DEBUG_TYPE "instsimplify" +#include "llvm/GlobalAlias.h" +#include "llvm/Operator.h" +#include "llvm/ADT/Statistic.h" +#include "llvm/ADT/SetVector.h" +#include "llvm/Analysis/InstructionSimplify.h" +#include "llvm/Analysis/AliasAnalysis.h" +#include "llvm/Analysis/ConstantFolding.h" +#include "llvm/Analysis/Dominators.h" +#include "llvm/Analysis/ValueTracking.h" +#include "llvm/Support/ConstantRange.h" +#include "llvm/Support/GetElementPtrTypeIterator.h" +#include "llvm/Support/PatternMatch.h" +#include "llvm/Support/ValueHandle.h" +#include "llvm/Target/TargetData.h" +using namespace llvm; +using namespace llvm::PatternMatch; + +enum { RecursionLimit = 3 }; + +STATISTIC(NumExpand, "Number of expansions"); +STATISTIC(NumFactor , "Number of factorizations"); +STATISTIC(NumReassoc, "Number of reassociations"); + +struct Query { + const TargetData *TD; + const TargetLibraryInfo *TLI; + const DominatorTree *DT; + + Query(const TargetData *td, const TargetLibraryInfo *tli, + const DominatorTree *dt) : TD(td), TLI(tli), DT(dt) {}; +}; + +static Value *SimplifyAndInst(Value *, Value *, const Query &, unsigned); +static Value *SimplifyBinOp(unsigned, Value *, Value *, const Query &, + unsigned); +static Value *SimplifyCmpInst(unsigned, Value *, Value *, const Query &, + unsigned); +static Value *SimplifyOrInst(Value *, Value *, const Query &, unsigned); +static Value *SimplifyXorInst(Value *, Value *, const Query &, unsigned); +static Value *SimplifyTruncInst(Value *, Type *, const Query &, unsigned); + +/// getFalse - For a boolean type, or a vector of boolean type, return false, or +/// a vector with every element false, as appropriate for the type. +static Constant *getFalse(Type *Ty) { + assert(Ty->getScalarType()->isIntegerTy(1) && + "Expected i1 type or a vector of i1!"); + return Constant::getNullValue(Ty); +} + +/// getTrue - For a boolean type, or a vector of boolean type, return true, or +/// a vector with every element true, as appropriate for the type. +static Constant *getTrue(Type *Ty) { + assert(Ty->getScalarType()->isIntegerTy(1) && + "Expected i1 type or a vector of i1!"); + return Constant::getAllOnesValue(Ty); +} + +/// isSameCompare - Is V equivalent to the comparison "LHS Pred RHS"? +static bool isSameCompare(Value *V, CmpInst::Predicate Pred, Value *LHS, + Value *RHS) { + CmpInst *Cmp = dyn_cast<CmpInst>(V); + if (!Cmp) + return false; + CmpInst::Predicate CPred = Cmp->getPredicate(); + Value *CLHS = Cmp->getOperand(0), *CRHS = Cmp->getOperand(1); + if (CPred == Pred && CLHS == LHS && CRHS == RHS) + return true; + return CPred == CmpInst::getSwappedPredicate(Pred) && CLHS == RHS && + CRHS == LHS; +} + +/// ValueDominatesPHI - Does the given value dominate the specified phi node? +static bool ValueDominatesPHI(Value *V, PHINode *P, const DominatorTree *DT) { + Instruction *I = dyn_cast<Instruction>(V); + if (!I) + // Arguments and constants dominate all instructions. + return true; + + // If we are processing instructions (and/or basic blocks) that have not been + // fully added to a function, the parent nodes may still be null. Simply + // return the conservative answer in these cases. + if (!I->getParent() || !P->getParent() || !I->getParent()->getParent()) + return false; + + // If we have a DominatorTree then do a precise test. + if (DT) { + if (!DT->isReachableFromEntry(P->getParent())) + return true; + if (!DT->isReachableFromEntry(I->getParent())) + return false; + return DT->dominates(I, P); + } + + // Otherwise, if the instruction is in the entry block, and is not an invoke, + // then it obviously dominates all phi nodes. + if (I->getParent() == &I->getParent()->getParent()->getEntryBlock() && + !isa<InvokeInst>(I)) + return true; + + return false; +} + +/// ExpandBinOp - Simplify "A op (B op' C)" by distributing op over op', turning +/// it into "(A op B) op' (A op C)". Here "op" is given by Opcode and "op'" is +/// given by OpcodeToExpand, while "A" corresponds to LHS and "B op' C" to RHS. +/// Also performs the transform "(A op' B) op C" -> "(A op C) op' (B op C)". +/// Returns the simplified value, or null if no simplification was performed. +static Value *ExpandBinOp(unsigned Opcode, Value *LHS, Value *RHS, + unsigned OpcToExpand, const Query &Q, + unsigned MaxRecurse) { + Instruction::BinaryOps OpcodeToExpand = (Instruction::BinaryOps)OpcToExpand; + // Recursion is always used, so bail out at once if we already hit the limit. + if (!MaxRecurse--) + return 0; + + // Check whether the expression has the form "(A op' B) op C". + if (BinaryOperator *Op0 = dyn_cast<BinaryOperator>(LHS)) + if (Op0->getOpcode() == OpcodeToExpand) { + // It does! Try turning it into "(A op C) op' (B op C)". + Value *A = Op0->getOperand(0), *B = Op0->getOperand(1), *C = RHS; + // Do "A op C" and "B op C" both simplify? + if (Value *L = SimplifyBinOp(Opcode, A, C, Q, MaxRecurse)) + if (Value *R = SimplifyBinOp(Opcode, B, C, Q, MaxRecurse)) { + // They do! Return "L op' R" if it simplifies or is already available. + // If "L op' R" equals "A op' B" then "L op' R" is just the LHS. + if ((L == A && R == B) || (Instruction::isCommutative(OpcodeToExpand) + && L == B && R == A)) { + ++NumExpand; + return LHS; + } + // Otherwise return "L op' R" if it simplifies. + if (Value *V = SimplifyBinOp(OpcodeToExpand, L, R, Q, MaxRecurse)) { + ++NumExpand; + return V; + } + } + } + + // Check whether the expression has the form "A op (B op' C)". + if (BinaryOperator *Op1 = dyn_cast<BinaryOperator>(RHS)) + if (Op1->getOpcode() == OpcodeToExpand) { + // It does! Try turning it into "(A op B) op' (A op C)". + Value *A = LHS, *B = Op1->getOperand(0), *C = Op1->getOperand(1); + // Do "A op B" and "A op C" both simplify? + if (Value *L = SimplifyBinOp(Opcode, A, B, Q, MaxRecurse)) + if (Value *R = SimplifyBinOp(Opcode, A, C, Q, MaxRecurse)) { + // They do! Return "L op' R" if it simplifies or is already available. + // If "L op' R" equals "B op' C" then "L op' R" is just the RHS. + if ((L == B && R == C) || (Instruction::isCommutative(OpcodeToExpand) + && L == C && R == B)) { + ++NumExpand; + return RHS; + } + // Otherwise return "L op' R" if it simplifies. + if (Value *V = SimplifyBinOp(OpcodeToExpand, L, R, Q, MaxRecurse)) { + ++NumExpand; + return V; + } + } + } + + return 0; +} + +/// FactorizeBinOp - Simplify "LHS Opcode RHS" by factorizing out a common term +/// using the operation OpCodeToExtract. For example, when Opcode is Add and +/// OpCodeToExtract is Mul then this tries to turn "(A*B)+(A*C)" into "A*(B+C)". +/// Returns the simplified value, or null if no simplification was performed. +static Value *FactorizeBinOp(unsigned Opcode, Value *LHS, Value *RHS, + unsigned OpcToExtract, const Query &Q, + unsigned MaxRecurse) { + Instruction::BinaryOps OpcodeToExtract = (Instruction::BinaryOps)OpcToExtract; + // Recursion is always used, so bail out at once if we already hit the limit. + if (!MaxRecurse--) + return 0; + + BinaryOperator *Op0 = dyn_cast<BinaryOperator>(LHS); + BinaryOperator *Op1 = dyn_cast<BinaryOperator>(RHS); + + if (!Op0 || Op0->getOpcode() != OpcodeToExtract || + !Op1 || Op1->getOpcode() != OpcodeToExtract) + return 0; + + // The expression has the form "(A op' B) op (C op' D)". + Value *A = Op0->getOperand(0), *B = Op0->getOperand(1); + Value *C = Op1->getOperand(0), *D = Op1->getOperand(1); + + // Use left distributivity, i.e. "X op' (Y op Z) = (X op' Y) op (X op' Z)". + // Does the instruction have the form "(A op' B) op (A op' D)" or, in the + // commutative case, "(A op' B) op (C op' A)"? + if (A == C || (Instruction::isCommutative(OpcodeToExtract) && A == D)) { + Value *DD = A == C ? D : C; + // Form "A op' (B op DD)" if it simplifies completely. + // Does "B op DD" simplify? + if (Value *V = SimplifyBinOp(Opcode, B, DD, Q, MaxRecurse)) { + // It does! Return "A op' V" if it simplifies or is already available. + // If V equals B then "A op' V" is just the LHS. If V equals DD then + // "A op' V" is just the RHS. + if (V == B || V == DD) { + ++NumFactor; + return V == B ? LHS : RHS; + } + // Otherwise return "A op' V" if it simplifies. + if (Value *W = SimplifyBinOp(OpcodeToExtract, A, V, Q, MaxRecurse)) { + ++NumFactor; + return W; + } + } + } + + // Use right distributivity, i.e. "(X op Y) op' Z = (X op' Z) op (Y op' Z)". + // Does the instruction have the form "(A op' B) op (C op' B)" or, in the + // commutative case, "(A op' B) op (B op' D)"? + if (B == D || (Instruction::isCommutative(OpcodeToExtract) && B == C)) { + Value *CC = B == D ? C : D; + // Form "(A op CC) op' B" if it simplifies completely.. + // Does "A op CC" simplify? + if (Value *V = SimplifyBinOp(Opcode, A, CC, Q, MaxRecurse)) { + // It does! Return "V op' B" if it simplifies or is already available. + // If V equals A then "V op' B" is just the LHS. If V equals CC then + // "V op' B" is just the RHS. + if (V == A || V == CC) { + ++NumFactor; + return V == A ? LHS : RHS; + } + // Otherwise return "V op' B" if it simplifies. + if (Value *W = SimplifyBinOp(OpcodeToExtract, V, B, Q, MaxRecurse)) { + ++NumFactor; + return W; + } + } + } + + return 0; +} + +/// SimplifyAssociativeBinOp - Generic simplifications for associative binary +/// operations. Returns the simpler value, or null if none was found. +static Value *SimplifyAssociativeBinOp(unsigned Opc, Value *LHS, Value *RHS, + const Query &Q, unsigned MaxRecurse) { + Instruction::BinaryOps Opcode = (Instruction::BinaryOps)Opc; + assert(Instruction::isAssociative(Opcode) && "Not an associative operation!"); + + // Recursion is always used, so bail out at once if we already hit the limit. + if (!MaxRecurse--) + return 0; + + BinaryOperator *Op0 = dyn_cast<BinaryOperator>(LHS); + BinaryOperator *Op1 = dyn_cast<BinaryOperator>(RHS); + + // Transform: "(A op B) op C" ==> "A op (B op C)" if it simplifies completely. + if (Op0 && Op0->getOpcode() == Opcode) { + Value *A = Op0->getOperand(0); + Value *B = Op0->getOperand(1); + Value *C = RHS; + + // Does "B op C" simplify? + if (Value *V = SimplifyBinOp(Opcode, B, C, Q, MaxRecurse)) { + // It does! Return "A op V" if it simplifies or is already available. + // If V equals B then "A op V" is just the LHS. + if (V == B) return LHS; + // Otherwise return "A op V" if it simplifies. + if (Value *W = SimplifyBinOp(Opcode, A, V, Q, MaxRecurse)) { + ++NumReassoc; + return W; + } + } + } + + // Transform: "A op (B op C)" ==> "(A op B) op C" if it simplifies completely. + if (Op1 && Op1->getOpcode() == Opcode) { + Value *A = LHS; + Value *B = Op1->getOperand(0); + Value *C = Op1->getOperand(1); + + // Does "A op B" simplify? + if (Value *V = SimplifyBinOp(Opcode, A, B, Q, MaxRecurse)) { + // It does! Return "V op C" if it simplifies or is already available. + // If V equals B then "V op C" is just the RHS. + if (V == B) return RHS; + // Otherwise return "V op C" if it simplifies. + if (Value *W = SimplifyBinOp(Opcode, V, C, Q, MaxRecurse)) { + ++NumReassoc; + return W; + } + } + } + + // The remaining transforms require commutativity as well as associativity. + if (!Instruction::isCommutative(Opcode)) + return 0; + + // Transform: "(A op B) op C" ==> "(C op A) op B" if it simplifies completely. + if (Op0 && Op0->getOpcode() == Opcode) { + Value *A = Op0->getOperand(0); + Value *B = Op0->getOperand(1); + Value *C = RHS; + + // Does "C op A" simplify? + if (Value *V = SimplifyBinOp(Opcode, C, A, Q, MaxRecurse)) { + // It does! Return "V op B" if it simplifies or is already available. + // If V equals A then "V op B" is just the LHS. + if (V == A) return LHS; + // Otherwise return "V op B" if it simplifies. + if (Value *W = SimplifyBinOp(Opcode, V, B, Q, MaxRecurse)) { + ++NumReassoc; + return W; + } + } + } + + // Transform: "A op (B op C)" ==> "B op (C op A)" if it simplifies completely. + if (Op1 && Op1->getOpcode() == Opcode) { + Value *A = LHS; + Value *B = Op1->getOperand(0); + Value *C = Op1->getOperand(1); + + // Does "C op A" simplify? + if (Value *V = SimplifyBinOp(Opcode, C, A, Q, MaxRecurse)) { + // It does! Return "B op V" if it simplifies or is already available. + // If V equals C then "B op V" is just the RHS. + if (V == C) return RHS; + // Otherwise return "B op V" if it simplifies. + if (Value *W = SimplifyBinOp(Opcode, B, V, Q, MaxRecurse)) { + ++NumReassoc; + return W; + } + } + } + + return 0; +} + +/// ThreadBinOpOverSelect - In the case of a binary operation with a select +/// instruction as an operand, try to simplify the binop by seeing whether +/// evaluating it on both branches of the select results in the same value. +/// Returns the common value if so, otherwise returns null. +static Value *ThreadBinOpOverSelect(unsigned Opcode, Value *LHS, Value *RHS, + const Query &Q, unsigned MaxRecurse) { + // Recursion is always used, so bail out at once if we already hit the limit. + if (!MaxRecurse--) + return 0; + + SelectInst *SI; + if (isa<SelectInst>(LHS)) { + SI = cast<SelectInst>(LHS); + } else { + assert(isa<SelectInst>(RHS) && "No select instruction operand!"); + SI = cast<SelectInst>(RHS); + } + + // Evaluate the BinOp on the true and false branches of the select. + Value *TV; + Value *FV; + if (SI == LHS) { + TV = SimplifyBinOp(Opcode, SI->getTrueValue(), RHS, Q, MaxRecurse); + FV = SimplifyBinOp(Opcode, SI->getFalseValue(), RHS, Q, MaxRecurse); + } else { + TV = SimplifyBinOp(Opcode, LHS, SI->getTrueValue(), Q, MaxRecurse); + FV = SimplifyBinOp(Opcode, LHS, SI->getFalseValue(), Q, MaxRecurse); + } + + // If they simplified to the same value, then return the common value. + // If they both failed to simplify then return null. + if (TV == FV) + return TV; + + // If one branch simplified to undef, return the other one. + if (TV && isa<UndefValue>(TV)) + return FV; + if (FV && isa<UndefValue>(FV)) + return TV; + + // If applying the operation did not change the true and false select values, + // then the result of the binop is the select itself. + if (TV == SI->getTrueValue() && FV == SI->getFalseValue()) + return SI; + + // If one branch simplified and the other did not, and the simplified + // value is equal to the unsimplified one, return the simplified value. + // For example, select (cond, X, X & Z) & Z -> X & Z. + if ((FV && !TV) || (TV && !FV)) { + // Check that the simplified value has the form "X op Y" where "op" is the + // same as the original operation. + Instruction *Simplified = dyn_cast<Instruction>(FV ? FV : TV); + if (Simplified && Simplified->getOpcode() == Opcode) { + // The value that didn't simplify is "UnsimplifiedLHS op UnsimplifiedRHS". + // We already know that "op" is the same as for the simplified value. See + // if the operands match too. If so, return the simplified value. + Value *UnsimplifiedBranch = FV ? SI->getTrueValue() : SI->getFalseValue(); + Value *UnsimplifiedLHS = SI == LHS ? UnsimplifiedBranch : LHS; + Value *UnsimplifiedRHS = SI == LHS ? RHS : UnsimplifiedBranch; + if (Simplified->getOperand(0) == UnsimplifiedLHS && + Simplified->getOperand(1) == UnsimplifiedRHS) + return Simplified; + if (Simplified->isCommutative() && + Simplified->getOperand(1) == UnsimplifiedLHS && + Simplified->getOperand(0) == UnsimplifiedRHS) + return Simplified; + } + } + + return 0; +} + +/// ThreadCmpOverSelect - In the case of a comparison with a select instruction, +/// try to simplify the comparison by seeing whether both branches of the select +/// result in the same value. Returns the common value if so, otherwise returns +/// null. +static Value *ThreadCmpOverSelect(CmpInst::Predicate Pred, Value *LHS, + Value *RHS, const Query &Q, + unsigned MaxRecurse) { + // Recursion is always used, so bail out at once if we already hit the limit. + if (!MaxRecurse--) + return 0; + + // Make sure the select is on the LHS. + if (!isa<SelectInst>(LHS)) { + std::swap(LHS, RHS); + Pred = CmpInst::getSwappedPredicate(Pred); + } + assert(isa<SelectInst>(LHS) && "Not comparing with a select instruction!"); + SelectInst *SI = cast<SelectInst>(LHS); + Value *Cond = SI->getCondition(); + Value *TV = SI->getTrueValue(); + Value *FV = SI->getFalseValue(); + + // Now that we have "cmp select(Cond, TV, FV), RHS", analyse it. + // Does "cmp TV, RHS" simplify? + Value *TCmp = SimplifyCmpInst(Pred, TV, RHS, Q, MaxRecurse); + if (TCmp == Cond) { + // It not only simplified, it simplified to the select condition. Replace + // it with 'true'. + TCmp = getTrue(Cond->getType()); + } else if (!TCmp) { + // It didn't simplify. However if "cmp TV, RHS" is equal to the select + // condition then we can replace it with 'true'. Otherwise give up. + if (!isSameCompare(Cond, Pred, TV, RHS)) + return 0; + TCmp = getTrue(Cond->getType()); + } + + // Does "cmp FV, RHS" simplify? + Value *FCmp = SimplifyCmpInst(Pred, FV, RHS, Q, MaxRecurse); + if (FCmp == Cond) { + // It not only simplified, it simplified to the select condition. Replace + // it with 'false'. + FCmp = getFalse(Cond->getType()); + } else if (!FCmp) { + // It didn't simplify. However if "cmp FV, RHS" is equal to the select + // condition then we can replace it with 'false'. Otherwise give up. + if (!isSameCompare(Cond, Pred, FV, RHS)) + return 0; + FCmp = getFalse(Cond->getType()); + } + + // If both sides simplified to the same value, then use it as the result of + // the original comparison. + if (TCmp == FCmp) + return TCmp; + + // The remaining cases only make sense if the select condition has the same + // type as the result of the comparison, so bail out if this is not so. + if (Cond->getType()->isVectorTy() != RHS->getType()->isVectorTy()) + return 0; + // If the false value simplified to false, then the result of the compare + // is equal to "Cond && TCmp". This also catches the case when the false + // value simplified to false and the true value to true, returning "Cond". + if (match(FCmp, m_Zero())) + if (Value *V = SimplifyAndInst(Cond, TCmp, Q, MaxRecurse)) + return V; + // If the true value simplified to true, then the result of the compare + // is equal to "Cond || FCmp". + if (match(TCmp, m_One())) + if (Value *V = SimplifyOrInst(Cond, FCmp, Q, MaxRecurse)) + return V; + // Finally, if the false value simplified to true and the true value to + // false, then the result of the compare is equal to "!Cond". + if (match(FCmp, m_One()) && match(TCmp, m_Zero())) + if (Value *V = + SimplifyXorInst(Cond, Constant::getAllOnesValue(Cond->getType()), + Q, MaxRecurse)) + return V; + + return 0; +} + +/// ThreadBinOpOverPHI - In the case of a binary operation with an operand that +/// is a PHI instruction, try to simplify the binop by seeing whether evaluating +/// it on the incoming phi values yields the same result for every value. If so +/// returns the common value, otherwise returns null. +static Value *ThreadBinOpOverPHI(unsigned Opcode, Value *LHS, Value *RHS, + const Query &Q, unsigned MaxRecurse) { + // Recursion is always used, so bail out at once if we already hit the limit. + if (!MaxRecurse--) + return 0; + + PHINode *PI; + if (isa<PHINode>(LHS)) { + PI = cast<PHINode>(LHS); + // Bail out if RHS and the phi may be mutually interdependent due to a loop. + if (!ValueDominatesPHI(RHS, PI, Q.DT)) + return 0; + } else { + assert(isa<PHINode>(RHS) && "No PHI instruction operand!"); + PI = cast<PHINode>(RHS); + // Bail out if LHS and the phi may be mutually interdependent due to a loop. + if (!ValueDominatesPHI(LHS, PI, Q.DT)) + return 0; + } + + // Evaluate the BinOp on the incoming phi values. + Value *CommonValue = 0; + for (unsigned i = 0, e = PI->getNumIncomingValues(); i != e; ++i) { + Value *Incoming = PI->getIncomingValue(i); + // If the incoming value is the phi node itself, it can safely be skipped. + if (Incoming == PI) continue; + Value *V = PI == LHS ? + SimplifyBinOp(Opcode, Incoming, RHS, Q, MaxRecurse) : + SimplifyBinOp(Opcode, LHS, Incoming, Q, MaxRecurse); + // If the operation failed to simplify, or simplified to a different value + // to previously, then give up. + if (!V || (CommonValue && V != CommonValue)) + return 0; + CommonValue = V; + } + + return CommonValue; +} + +/// ThreadCmpOverPHI - In the case of a comparison with a PHI instruction, try +/// try to simplify the comparison by seeing whether comparing with all of the +/// incoming phi values yields the same result every time. If so returns the +/// common result, otherwise returns null. +static Value *ThreadCmpOverPHI(CmpInst::Predicate Pred, Value *LHS, Value *RHS, + const Query &Q, unsigned MaxRecurse) { + // Recursion is always used, so bail out at once if we already hit the limit. + if (!MaxRecurse--) + return 0; + + // Make sure the phi is on the LHS. + if (!isa<PHINode>(LHS)) { + std::swap(LHS, RHS); + Pred = CmpInst::getSwappedPredicate(Pred); + } + assert(isa<PHINode>(LHS) && "Not comparing with a phi instruction!"); + PHINode *PI = cast<PHINode>(LHS); + + // Bail out if RHS and the phi may be mutually interdependent due to a loop. + if (!ValueDominatesPHI(RHS, PI, Q.DT)) + return 0; + + // Evaluate the BinOp on the incoming phi values. + Value *CommonValue = 0; + for (unsigned i = 0, e = PI->getNumIncomingValues(); i != e; ++i) { + Value *Incoming = PI->getIncomingValue(i); + // If the incoming value is the phi node itself, it can safely be skipped. + if (Incoming == PI) continue; + Value *V = SimplifyCmpInst(Pred, Incoming, RHS, Q, MaxRecurse); + // If the operation failed to simplify, or simplified to a different value + // to previously, then give up. + if (!V || (CommonValue && V != CommonValue)) + return 0; + CommonValue = V; + } + + return CommonValue; +} + +/// SimplifyAddInst - Given operands for an Add, see if we can +/// fold the result. If not, this returns null. +static Value *SimplifyAddInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW, + const Query &Q, unsigned MaxRecurse) { + if (Constant *CLHS = dyn_cast<Constant>(Op0)) { + if (Constant *CRHS = dyn_cast<Constant>(Op1)) { + Constant *Ops[] = { CLHS, CRHS }; + return ConstantFoldInstOperands(Instruction::Add, CLHS->getType(), Ops, + Q.TD, Q.TLI); + } + + // Canonicalize the constant to the RHS. + std::swap(Op0, Op1); + } + + // X + undef -> undef + if (match(Op1, m_Undef())) + return Op1; + + // X + 0 -> X + if (match(Op1, m_Zero())) + return Op0; + + // X + (Y - X) -> Y + // (Y - X) + X -> Y + // Eg: X + -X -> 0 + Value *Y = 0; + if (match(Op1, m_Sub(m_Value(Y), m_Specific(Op0))) || + match(Op0, m_Sub(m_Value(Y), m_Specific(Op1)))) + return Y; + + // X + ~X -> -1 since ~X = -X-1 + if (match(Op0, m_Not(m_Specific(Op1))) || + match(Op1, m_Not(m_Specific(Op0)))) + return Constant::getAllOnesValue(Op0->getType()); + + /// i1 add -> xor. + if (MaxRecurse && Op0->getType()->isIntegerTy(1)) + if (Value *V = SimplifyXorInst(Op0, Op1, Q, MaxRecurse-1)) + return V; + + // Try some generic simplifications for associative operations. + if (Value *V = SimplifyAssociativeBinOp(Instruction::Add, Op0, Op1, Q, + MaxRecurse)) + return V; + + // Mul distributes over Add. Try some generic simplifications based on this. + if (Value *V = FactorizeBinOp(Instruction::Add, Op0, Op1, Instruction::Mul, + Q, MaxRecurse)) + return V; + + // Threading Add over selects and phi nodes is pointless, so don't bother. + // Threading over the select in "A + select(cond, B, C)" means evaluating + // "A+B" and "A+C" and seeing if they are equal; but they are equal if and + // only if B and C are equal. If B and C are equal then (since we assume + // that operands have already been simplified) "select(cond, B, C)" should + // have been simplified to the common value of B and C already. Analysing + // "A+B" and "A+C" thus gains nothing, but costs compile time. Similarly + // for threading over phi nodes. + + return 0; +} + +Value *llvm::SimplifyAddInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW, + const TargetData *TD, const TargetLibraryInfo *TLI, + const DominatorTree *DT) { + return ::SimplifyAddInst(Op0, Op1, isNSW, isNUW, Query (TD, TLI, DT), + RecursionLimit); +} + +/// \brief Accumulate the constant integer offset a GEP represents. +/// +/// Given a getelementptr instruction/constantexpr, accumulate the constant +/// offset from the base pointer into the provided APInt 'Offset'. Returns true +/// if the GEP has all-constant indices. Returns false if any non-constant +/// index is encountered leaving the 'Offset' in an undefined state. The +/// 'Offset' APInt must be the bitwidth of the target's pointer size. +static bool accumulateGEPOffset(const TargetData &TD, GEPOperator *GEP, + APInt &Offset) { + unsigned IntPtrWidth = TD.getPointerSizeInBits(); + assert(IntPtrWidth == Offset.getBitWidth()); + + gep_type_iterator GTI = gep_type_begin(GEP); + for (User::op_iterator I = GEP->op_begin() + 1, E = GEP->op_end(); I != E; + ++I, ++GTI) { + ConstantInt *OpC = dyn_cast<ConstantInt>(*I); + if (!OpC) return false; + if (OpC->isZero()) continue; + + // Handle a struct index, which adds its field offset to the pointer. + if (StructType *STy = dyn_cast<StructType>(*GTI)) { + unsigned ElementIdx = OpC->getZExtValue(); + const StructLayout *SL = TD.getStructLayout(STy); + Offset += APInt(IntPtrWidth, SL->getElementOffset(ElementIdx)); + continue; + } + + APInt TypeSize(IntPtrWidth, TD.getTypeAllocSize(GTI.getIndexedType())); + Offset += OpC->getValue().sextOrTrunc(IntPtrWidth) * TypeSize; + } + return true; +} + +/// \brief Compute the base pointer and cumulative constant offsets for V. +/// +/// This strips all constant offsets off of V, leaving it the base pointer, and +/// accumulates the total constant offset applied in the returned constant. It +/// returns 0 if V is not a pointer, and returns the constant '0' if there are +/// no constant offsets applied. +static Constant *stripAndComputeConstantOffsets(const TargetData &TD, + Value *&V) { + if (!V->getType()->isPointerTy()) + return 0; + + unsigned IntPtrWidth = TD.getPointerSizeInBits(); + APInt Offset = APInt::getNullValue(IntPtrWidth); + + // Even though we don't look through PHI nodes, we could be called on an + // instruction in an unreachable block, which may be on a cycle. + SmallPtrSet<Value *, 4> Visited; + Visited.insert(V); + do { + if (GEPOperator *GEP = dyn_cast<GEPOperator>(V)) { + if (!GEP->isInBounds() || !accumulateGEPOffset(TD, GEP, Offset)) + break; + V = GEP->getPointerOperand(); + } else if (Operator::getOpcode(V) == Instruction::BitCast) { + V = cast<Operator>(V)->getOperand(0); + } else if (GlobalAlias *GA = dyn_cast<GlobalAlias>(V)) { + if (GA->mayBeOverridden()) + break; + V = GA->getAliasee(); + } else { + break; + } + assert(V->getType()->isPointerTy() && "Unexpected operand type!"); + } while (Visited.insert(V)); + + Type *IntPtrTy = TD.getIntPtrType(V->getContext()); + return ConstantInt::get(IntPtrTy, Offset); +} + +/// \brief Compute the constant difference between two pointer values. +/// If the difference is not a constant, returns zero. +static Constant *computePointerDifference(const TargetData &TD, + Value *LHS, Value *RHS) { + Constant *LHSOffset = stripAndComputeConstantOffsets(TD, LHS); + if (!LHSOffset) + return 0; + Constant *RHSOffset = stripAndComputeConstantOffsets(TD, RHS); + if (!RHSOffset) + return 0; + + // If LHS and RHS are not related via constant offsets to the same base + // value, there is nothing we can do here. + if (LHS != RHS) + return 0; + + // Otherwise, the difference of LHS - RHS can be computed as: + // LHS - RHS + // = (LHSOffset + Base) - (RHSOffset + Base) + // = LHSOffset - RHSOffset + return ConstantExpr::getSub(LHSOffset, RHSOffset); +} + +/// SimplifySubInst - Given operands for a Sub, see if we can +/// fold the result. If not, this returns null. +static Value *SimplifySubInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW, + const Query &Q, unsigned MaxRecurse) { + if (Constant *CLHS = dyn_cast<Constant>(Op0)) + if (Constant *CRHS = dyn_cast<Constant>(Op1)) { + Constant *Ops[] = { CLHS, CRHS }; + return ConstantFoldInstOperands(Instruction::Sub, CLHS->getType(), + Ops, Q.TD, Q.TLI); + } + + // X - undef -> undef + // undef - X -> undef + if (match(Op0, m_Undef()) || match(Op1, m_Undef())) + return UndefValue::get(Op0->getType()); + + // X - 0 -> X + if (match(Op1, m_Zero())) + return Op0; + + // X - X -> 0 + if (Op0 == Op1) + return Constant::getNullValue(Op0->getType()); + + // (X*2) - X -> X + // (X<<1) - X -> X + Value *X = 0; + if (match(Op0, m_Mul(m_Specific(Op1), m_ConstantInt<2>())) || + match(Op0, m_Shl(m_Specific(Op1), m_One()))) + return Op1; + + // (X + Y) - Z -> X + (Y - Z) or Y + (X - Z) if everything simplifies. + // For example, (X + Y) - Y -> X; (Y + X) - Y -> X + Value *Y = 0, *Z = Op1; + if (MaxRecurse && match(Op0, m_Add(m_Value(X), m_Value(Y)))) { // (X + Y) - Z + // See if "V === Y - Z" simplifies. + if (Value *V = SimplifyBinOp(Instruction::Sub, Y, Z, Q, MaxRecurse-1)) + // It does! Now see if "X + V" simplifies. + if (Value *W = SimplifyBinOp(Instruction::Add, X, V, Q, MaxRecurse-1)) { + // It does, we successfully reassociated! + ++NumReassoc; + return W; + } + // See if "V === X - Z" simplifies. + if (Value *V = SimplifyBinOp(Instruction::Sub, X, Z, Q, MaxRecurse-1)) + // It does! Now see if "Y + V" simplifies. + if (Value *W = SimplifyBinOp(Instruction::Add, Y, V, Q, MaxRecurse-1)) { + // It does, we successfully reassociated! + ++NumReassoc; + return W; + } + } + + // X - (Y + Z) -> (X - Y) - Z or (X - Z) - Y if everything simplifies. + // For example, X - (X + 1) -> -1 + X = Op0; + if (MaxRecurse && match(Op1, m_Add(m_Value(Y), m_Value(Z)))) { // X - (Y + Z) + // See if "V === X - Y" simplifies. + if (Value *V = SimplifyBinOp(Instruction::Sub, X, Y, Q, MaxRecurse-1)) + // It does! Now see if "V - Z" simplifies. + if (Value *W = SimplifyBinOp(Instruction::Sub, V, Z, Q, MaxRecurse-1)) { + // It does, we successfully reassociated! + ++NumReassoc; + return W; + } + // See if "V === X - Z" simplifies. + if (Value *V = SimplifyBinOp(Instruction::Sub, X, Z, Q, MaxRecurse-1)) + // It does! Now see if "V - Y" simplifies. + if (Value *W = SimplifyBinOp(Instruction::Sub, V, Y, Q, MaxRecurse-1)) { + // It does, we successfully reassociated! + ++NumReassoc; + return W; + } + } + + // Z - (X - Y) -> (Z - X) + Y if everything simplifies. + // For example, X - (X - Y) -> Y. + Z = Op0; + if (MaxRecurse && match(Op1, m_Sub(m_Value(X), m_Value(Y)))) // Z - (X - Y) + // See if "V === Z - X" simplifies. + if (Value *V = SimplifyBinOp(Instruction::Sub, Z, X, Q, MaxRecurse-1)) + // It does! Now see if "V + Y" simplifies. + if (Value *W = SimplifyBinOp(Instruction::Add, V, Y, Q, MaxRecurse-1)) { + // It does, we successfully reassociated! + ++NumReassoc; + return W; + } + + // trunc(X) - trunc(Y) -> trunc(X - Y) if everything simplifies. + if (MaxRecurse && match(Op0, m_Trunc(m_Value(X))) && + match(Op1, m_Trunc(m_Value(Y)))) + if (X->getType() == Y->getType()) + // See if "V === X - Y" simplifies. + if (Value *V = SimplifyBinOp(Instruction::Sub, X, Y, Q, MaxRecurse-1)) + // It does! Now see if "trunc V" simplifies. + if (Value *W = SimplifyTruncInst(V, Op0->getType(), Q, MaxRecurse-1)) + // It does, return the simplified "trunc V". + return W; + + // Variations on GEP(base, I, ...) - GEP(base, i, ...) -> GEP(null, I-i, ...). + if (Q.TD && match(Op0, m_PtrToInt(m_Value(X))) && + match(Op1, m_PtrToInt(m_Value(Y)))) + if (Constant *Result = computePointerDifference(*Q.TD, X, Y)) + return ConstantExpr::getIntegerCast(Result, Op0->getType(), true); + + // Mul distributes over Sub. Try some generic simplifications based on this. + if (Value *V = FactorizeBinOp(Instruction::Sub, Op0, Op1, Instruction::Mul, + Q, MaxRecurse)) + return V; + + // i1 sub -> xor. + if (MaxRecurse && Op0->getType()->isIntegerTy(1)) + if (Value *V = SimplifyXorInst(Op0, Op1, Q, MaxRecurse-1)) + return V; + + // Threading Sub over selects and phi nodes is pointless, so don't bother. + // Threading over the select in "A - select(cond, B, C)" means evaluating + // "A-B" and "A-C" and seeing if they are equal; but they are equal if and + // only if B and C are equal. If B and C are equal then (since we assume + // that operands have already been simplified) "select(cond, B, C)" should + // have been simplified to the common value of B and C already. Analysing + // "A-B" and "A-C" thus gains nothing, but costs compile time. Similarly + // for threading over phi nodes. + + return 0; +} + +Value *llvm::SimplifySubInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW, + const TargetData *TD, const TargetLibraryInfo *TLI, + const DominatorTree *DT) { + return ::SimplifySubInst(Op0, Op1, isNSW, isNUW, Query (TD, TLI, DT), + RecursionLimit); +} + +/// SimplifyMulInst - Given operands for a Mul, see if we can +/// fold the result. If not, this returns null. +static Value *SimplifyMulInst(Value *Op0, Value *Op1, const Query &Q, + unsigned MaxRecurse) { + if (Constant *CLHS = dyn_cast<Constant>(Op0)) { + if (Constant *CRHS = dyn_cast<Constant>(Op1)) { + Constant *Ops[] = { CLHS, CRHS }; + return ConstantFoldInstOperands(Instruction::Mul, CLHS->getType(), + Ops, Q.TD, Q.TLI); + } + + // Canonicalize the constant to the RHS. + std::swap(Op0, Op1); + } + + // X * undef -> 0 + if (match(Op1, m_Undef())) + return Constant::getNullValue(Op0->getType()); + + // X * 0 -> 0 + if (match(Op1, m_Zero())) + return Op1; + + // X * 1 -> X + if (match(Op1, m_One())) + return Op0; + + // (X / Y) * Y -> X if the division is exact. + Value *X = 0; + if (match(Op0, m_Exact(m_IDiv(m_Value(X), m_Specific(Op1)))) || // (X / Y) * Y + match(Op1, m_Exact(m_IDiv(m_Value(X), m_Specific(Op0))))) // Y * (X / Y) + return X; + + // i1 mul -> and. + if (MaxRecurse && Op0->getType()->isIntegerTy(1)) + if (Value *V = SimplifyAndInst(Op0, Op1, Q, MaxRecurse-1)) + return V; + + // Try some generic simplifications for associative operations. + if (Value *V = SimplifyAssociativeBinOp(Instruction::Mul, Op0, Op1, Q, + MaxRecurse)) + return V; + + // Mul distributes over Add. Try some generic simplifications based on this. + if (Value *V = ExpandBinOp(Instruction::Mul, Op0, Op1, Instruction::Add, + Q, MaxRecurse)) + return V; + + // If the operation is with the result of a select instruction, check whether + // operating on either branch of the select always yields the same value. + if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1)) + if (Value *V = ThreadBinOpOverSelect(Instruction::Mul, Op0, Op1, Q, + MaxRecurse)) + return V; + + // If the operation is with the result of a phi instruction, check whether + // operating on all incoming values of the phi always yields the same value. + if (isa<PHINode>(Op0) || isa<PHINode>(Op1)) + if (Value *V = ThreadBinOpOverPHI(Instruction::Mul, Op0, Op1, Q, + MaxRecurse)) + return V; + + return 0; +} + +Value *llvm::SimplifyMulInst(Value *Op0, Value *Op1, const TargetData *TD, + const TargetLibraryInfo *TLI, + const DominatorTree *DT) { + return ::SimplifyMulInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit); +} + +/// SimplifyDiv - Given operands for an SDiv or UDiv, see if we can +/// fold the result. If not, this returns null. +static Value *SimplifyDiv(Instruction::BinaryOps Opcode, Value *Op0, Value *Op1, + const Query &Q, unsigned MaxRecurse) { + if (Constant *C0 = dyn_cast<Constant>(Op0)) { + if (Constant *C1 = dyn_cast<Constant>(Op1)) { + Constant *Ops[] = { C0, C1 }; + return ConstantFoldInstOperands(Opcode, C0->getType(), Ops, Q.TD, Q.TLI); + } + } + + bool isSigned = Opcode == Instruction::SDiv; + + // X / undef -> undef + if (match(Op1, m_Undef())) + return Op1; + + // undef / X -> 0 + if (match(Op0, m_Undef())) + return Constant::getNullValue(Op0->getType()); + + // 0 / X -> 0, we don't need to preserve faults! + if (match(Op0, m_Zero())) + return Op0; + + // X / 1 -> X + if (match(Op1, m_One())) + return Op0; + + if (Op0->getType()->isIntegerTy(1)) + // It can't be division by zero, hence it must be division by one. + return Op0; + + // X / X -> 1 + if (Op0 == Op1) + return ConstantInt::get(Op0->getType(), 1); + + // (X * Y) / Y -> X if the multiplication does not overflow. + Value *X = 0, *Y = 0; + if (match(Op0, m_Mul(m_Value(X), m_Value(Y))) && (X == Op1 || Y == Op1)) { + if (Y != Op1) std::swap(X, Y); // Ensure expression is (X * Y) / Y, Y = Op1 + OverflowingBinaryOperator *Mul = cast<OverflowingBinaryOperator>(Op0); + // If the Mul knows it does not overflow, then we are good to go. + if ((isSigned && Mul->hasNoSignedWrap()) || + (!isSigned && Mul->hasNoUnsignedWrap())) + return X; + // If X has the form X = A / Y then X * Y cannot overflow. + if (BinaryOperator *Div = dyn_cast<BinaryOperator>(X)) + if (Div->getOpcode() == Opcode && Div->getOperand(1) == Y) + return X; + } + + // (X rem Y) / Y -> 0 + if ((isSigned && match(Op0, m_SRem(m_Value(), m_Specific(Op1)))) || + (!isSigned && match(Op0, m_URem(m_Value(), m_Specific(Op1))))) + return Constant::getNullValue(Op0->getType()); + + // If the operation is with the result of a select instruction, check whether + // operating on either branch of the select always yields the same value. + if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1)) + if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, Q, MaxRecurse)) + return V; + + // If the operation is with the result of a phi instruction, check whether + // operating on all incoming values of the phi always yields the same value. + if (isa<PHINode>(Op0) || isa<PHINode>(Op1)) + if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse)) + return V; + + return 0; +} + +/// SimplifySDivInst - Given operands for an SDiv, see if we can +/// fold the result. If not, this returns null. +static Value *SimplifySDivInst(Value *Op0, Value *Op1, const Query &Q, + unsigned MaxRecurse) { + if (Value *V = SimplifyDiv(Instruction::SDiv, Op0, Op1, Q, MaxRecurse)) + return V; + + return 0; +} + +Value *llvm::SimplifySDivInst(Value *Op0, Value *Op1, const TargetData *TD, + const TargetLibraryInfo *TLI, + const DominatorTree *DT) { + return ::SimplifySDivInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit); +} + +/// SimplifyUDivInst - Given operands for a UDiv, see if we can +/// fold the result. If not, this returns null. +static Value *SimplifyUDivInst(Value *Op0, Value *Op1, const Query &Q, + unsigned MaxRecurse) { + if (Value *V = SimplifyDiv(Instruction::UDiv, Op0, Op1, Q, MaxRecurse)) + return V; + + return 0; +} + +Value *llvm::SimplifyUDivInst(Value *Op0, Value *Op1, const TargetData *TD, + const TargetLibraryInfo *TLI, + const DominatorTree *DT) { + return ::SimplifyUDivInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit); +} + +static Value *SimplifyFDivInst(Value *Op0, Value *Op1, const Query &Q, + unsigned) { + // undef / X -> undef (the undef could be a snan). + if (match(Op0, m_Undef())) + return Op0; + + // X / undef -> undef + if (match(Op1, m_Undef())) + return Op1; + + return 0; +} + +Value *llvm::SimplifyFDivInst(Value *Op0, Value *Op1, const TargetData *TD, + const TargetLibraryInfo *TLI, + const DominatorTree *DT) { + return ::SimplifyFDivInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit); +} + +/// SimplifyRem - Given operands for an SRem or URem, see if we can +/// fold the result. If not, this returns null. +static Value *SimplifyRem(Instruction::BinaryOps Opcode, Value *Op0, Value *Op1, + const Query &Q, unsigned MaxRecurse) { + if (Constant *C0 = dyn_cast<Constant>(Op0)) { + if (Constant *C1 = dyn_cast<Constant>(Op1)) { + Constant *Ops[] = { C0, C1 }; + return ConstantFoldInstOperands(Opcode, C0->getType(), Ops, Q.TD, Q.TLI); + } + } + + // X % undef -> undef + if (match(Op1, m_Undef())) + return Op1; + + // undef % X -> 0 + if (match(Op0, m_Undef())) + return Constant::getNullValue(Op0->getType()); + + // 0 % X -> 0, we don't need to preserve faults! + if (match(Op0, m_Zero())) + return Op0; + + // X % 0 -> undef, we don't need to preserve faults! + if (match(Op1, m_Zero())) + return UndefValue::get(Op0->getType()); + + // X % 1 -> 0 + if (match(Op1, m_One())) + return Constant::getNullValue(Op0->getType()); + + if (Op0->getType()->isIntegerTy(1)) + // It can't be remainder by zero, hence it must be remainder by one. + return Constant::getNullValue(Op0->getType()); + + // X % X -> 0 + if (Op0 == Op1) + return Constant::getNullValue(Op0->getType()); + + // If the operation is with the result of a select instruction, check whether + // operating on either branch of the select always yields the same value. + if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1)) + if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, Q, MaxRecurse)) + return V; + + // If the operation is with the result of a phi instruction, check whether + // operating on all incoming values of the phi always yields the same value. + if (isa<PHINode>(Op0) || isa<PHINode>(Op1)) + if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse)) + return V; + + return 0; +} + +/// SimplifySRemInst - Given operands for an SRem, see if we can +/// fold the result. If not, this returns null. +static Value *SimplifySRemInst(Value *Op0, Value *Op1, const Query &Q, + unsigned MaxRecurse) { + if (Value *V = SimplifyRem(Instruction::SRem, Op0, Op1, Q, MaxRecurse)) + return V; + + return 0; +} + +Value *llvm::SimplifySRemInst(Value *Op0, Value *Op1, const TargetData *TD, + const TargetLibraryInfo *TLI, + const DominatorTree *DT) { + return ::SimplifySRemInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit); +} + +/// SimplifyURemInst - Given operands for a URem, see if we can +/// fold the result. If not, this returns null. +static Value *SimplifyURemInst(Value *Op0, Value *Op1, const Query &Q, + unsigned MaxRecurse) { + if (Value *V = SimplifyRem(Instruction::URem, Op0, Op1, Q, MaxRecurse)) + return V; + + return 0; +} + +Value *llvm::SimplifyURemInst(Value *Op0, Value *Op1, const TargetData *TD, + const TargetLibraryInfo *TLI, + const DominatorTree *DT) { + return ::SimplifyURemInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit); +} + +static Value *SimplifyFRemInst(Value *Op0, Value *Op1, const Query &, + unsigned) { + // undef % X -> undef (the undef could be a snan). + if (match(Op0, m_Undef())) + return Op0; + + // X % undef -> undef + if (match(Op1, m_Undef())) + return Op1; + + return 0; +} + +Value *llvm::SimplifyFRemInst(Value *Op0, Value *Op1, const TargetData *TD, + const TargetLibraryInfo *TLI, + const DominatorTree *DT) { + return ::SimplifyFRemInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit); +} + +/// SimplifyShift - Given operands for an Shl, LShr or AShr, see if we can +/// fold the result. If not, this returns null. +static Value *SimplifyShift(unsigned Opcode, Value *Op0, Value *Op1, + const Query &Q, unsigned MaxRecurse) { + if (Constant *C0 = dyn_cast<Constant>(Op0)) { + if (Constant *C1 = dyn_cast<Constant>(Op1)) { + Constant *Ops[] = { C0, C1 }; + return ConstantFoldInstOperands(Opcode, C0->getType(), Ops, Q.TD, Q.TLI); + } + } + + // 0 shift by X -> 0 + if (match(Op0, m_Zero())) + return Op0; + + // X shift by 0 -> X + if (match(Op1, m_Zero())) + return Op0; + + // X shift by undef -> undef because it may shift by the bitwidth. + if (match(Op1, m_Undef())) + return Op1; + + // Shifting by the bitwidth or more is undefined. + if (ConstantInt *CI = dyn_cast<ConstantInt>(Op1)) + if (CI->getValue().getLimitedValue() >= + Op0->getType()->getScalarSizeInBits()) + return UndefValue::get(Op0->getType()); + + // If the operation is with the result of a select instruction, check whether + // operating on either branch of the select always yields the same value. + if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1)) + if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, Q, MaxRecurse)) + return V; + + // If the operation is with the result of a phi instruction, check whether + // operating on all incoming values of the phi always yields the same value. + if (isa<PHINode>(Op0) || isa<PHINode>(Op1)) + if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse)) + return V; + + return 0; +} + +/// SimplifyShlInst - Given operands for an Shl, see if we can +/// fold the result. If not, this returns null. +static Value *SimplifyShlInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW, + const Query &Q, unsigned MaxRecurse) { + if (Value *V = SimplifyShift(Instruction::Shl, Op0, Op1, Q, MaxRecurse)) + return V; + + // undef << X -> 0 + if (match(Op0, m_Undef())) + return Constant::getNullValue(Op0->getType()); + + // (X >> A) << A -> X + Value *X; + if (match(Op0, m_Exact(m_Shr(m_Value(X), m_Specific(Op1))))) + return X; + return 0; +} + +Value *llvm::SimplifyShlInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW, + const TargetData *TD, const TargetLibraryInfo *TLI, + const DominatorTree *DT) { + return ::SimplifyShlInst(Op0, Op1, isNSW, isNUW, Query (TD, TLI, DT), + RecursionLimit); +} + +/// SimplifyLShrInst - Given operands for an LShr, see if we can +/// fold the result. If not, this returns null. +static Value *SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact, + const Query &Q, unsigned MaxRecurse) { + if (Value *V = SimplifyShift(Instruction::LShr, Op0, Op1, Q, MaxRecurse)) + return V; + + // undef >>l X -> 0 + if (match(Op0, m_Undef())) + return Constant::getNullValue(Op0->getType()); + + // (X << A) >> A -> X + Value *X; + if (match(Op0, m_Shl(m_Value(X), m_Specific(Op1))) && + cast<OverflowingBinaryOperator>(Op0)->hasNoUnsignedWrap()) + return X; + + return 0; +} + +Value *llvm::SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact, + const TargetData *TD, + const TargetLibraryInfo *TLI, + const DominatorTree *DT) { + return ::SimplifyLShrInst(Op0, Op1, isExact, Query (TD, TLI, DT), + RecursionLimit); +} + +/// SimplifyAShrInst - Given operands for an AShr, see if we can +/// fold the result. If not, this returns null. +static Value *SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact, + const Query &Q, unsigned MaxRecurse) { + if (Value *V = SimplifyShift(Instruction::AShr, Op0, Op1, Q, MaxRecurse)) + return V; + + // all ones >>a X -> all ones + if (match(Op0, m_AllOnes())) + return Op0; + + // undef >>a X -> all ones + if (match(Op0, m_Undef())) + return Constant::getAllOnesValue(Op0->getType()); + + // (X << A) >> A -> X + Value *X; + if (match(Op0, m_Shl(m_Value(X), m_Specific(Op1))) && + cast<OverflowingBinaryOperator>(Op0)->hasNoSignedWrap()) + return X; + + return 0; +} + +Value *llvm::SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact, + const TargetData *TD, + const TargetLibraryInfo *TLI, + const DominatorTree *DT) { + return ::SimplifyAShrInst(Op0, Op1, isExact, Query (TD, TLI, DT), + RecursionLimit); +} + +/// SimplifyAndInst - Given operands for an And, see if we can +/// fold the result. If not, this returns null. +static Value *SimplifyAndInst(Value *Op0, Value *Op1, const Query &Q, + unsigned MaxRecurse) { + if (Constant *CLHS = dyn_cast<Constant>(Op0)) { + if (Constant *CRHS = dyn_cast<Constant>(Op1)) { + Constant *Ops[] = { CLHS, CRHS }; + return ConstantFoldInstOperands(Instruction::And, CLHS->getType(), + Ops, Q.TD, Q.TLI); + } + + // Canonicalize the constant to the RHS. + std::swap(Op0, Op1); + } + + // X & undef -> 0 + if (match(Op1, m_Undef())) + return Constant::getNullValue(Op0->getType()); + + // X & X = X + if (Op0 == Op1) + return Op0; + + // X & 0 = 0 + if (match(Op1, m_Zero())) + return Op1; + + // X & -1 = X + if (match(Op1, m_AllOnes())) + return Op0; + + // A & ~A = ~A & A = 0 + if (match(Op0, m_Not(m_Specific(Op1))) || + match(Op1, m_Not(m_Specific(Op0)))) + return Constant::getNullValue(Op0->getType()); + + // (A | ?) & A = A + Value *A = 0, *B = 0; + if (match(Op0, m_Or(m_Value(A), m_Value(B))) && + (A == Op1 || B == Op1)) + return Op1; + + // A & (A | ?) = A + if (match(Op1, m_Or(m_Value(A), m_Value(B))) && + (A == Op0 || B == Op0)) + return Op0; + + // A & (-A) = A if A is a power of two or zero. + if (match(Op0, m_Neg(m_Specific(Op1))) || + match(Op1, m_Neg(m_Specific(Op0)))) { + if (isPowerOfTwo(Op0, Q.TD, /*OrZero*/true)) + return Op0; + if (isPowerOfTwo(Op1, Q.TD, /*OrZero*/true)) + return Op1; + } + + // Try some generic simplifications for associative operations. + if (Value *V = SimplifyAssociativeBinOp(Instruction::And, Op0, Op1, Q, + MaxRecurse)) + return V; + + // And distributes over Or. Try some generic simplifications based on this. + if (Value *V = ExpandBinOp(Instruction::And, Op0, Op1, Instruction::Or, + Q, MaxRecurse)) + return V; + + // And distributes over Xor. Try some generic simplifications based on this. + if (Value *V = ExpandBinOp(Instruction::And, Op0, Op1, Instruction::Xor, + Q, MaxRecurse)) + return V; + + // Or distributes over And. Try some generic simplifications based on this. + if (Value *V = FactorizeBinOp(Instruction::And, Op0, Op1, Instruction::Or, + Q, MaxRecurse)) + return V; + + // If the operation is with the result of a select instruction, check whether + // operating on either branch of the select always yields the same value. + if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1)) + if (Value *V = ThreadBinOpOverSelect(Instruction::And, Op0, Op1, Q, + MaxRecurse)) + return V; + + // If the operation is with the result of a phi instruction, check whether + // operating on all incoming values of the phi always yields the same value. + if (isa<PHINode>(Op0) || isa<PHINode>(Op1)) + if (Value *V = ThreadBinOpOverPHI(Instruction::And, Op0, Op1, Q, + MaxRecurse)) + return V; + + return 0; +} + +Value *llvm::SimplifyAndInst(Value *Op0, Value *Op1, const TargetData *TD, + const TargetLibraryInfo *TLI, + const DominatorTree *DT) { + return ::SimplifyAndInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit); +} + +/// SimplifyOrInst - Given operands for an Or, see if we can +/// fold the result. If not, this returns null. +static Value *SimplifyOrInst(Value *Op0, Value *Op1, const Query &Q, + unsigned MaxRecurse) { + if (Constant *CLHS = dyn_cast<Constant>(Op0)) { + if (Constant *CRHS = dyn_cast<Constant>(Op1)) { + Constant *Ops[] = { CLHS, CRHS }; + return ConstantFoldInstOperands(Instruction::Or, CLHS->getType(), + Ops, Q.TD, Q.TLI); + } + + // Canonicalize the constant to the RHS. + std::swap(Op0, Op1); + } + + // X | undef -> -1 + if (match(Op1, m_Undef())) + return Constant::getAllOnesValue(Op0->getType()); + + // X | X = X + if (Op0 == Op1) + return Op0; + + // X | 0 = X + if (match(Op1, m_Zero())) + return Op0; + + // X | -1 = -1 + if (match(Op1, m_AllOnes())) + return Op1; + + // A | ~A = ~A | A = -1 + if (match(Op0, m_Not(m_Specific(Op1))) || + match(Op1, m_Not(m_Specific(Op0)))) + return Constant::getAllOnesValue(Op0->getType()); + + // (A & ?) | A = A + Value *A = 0, *B = 0; + if (match(Op0, m_And(m_Value(A), m_Value(B))) && + (A == Op1 || B == Op1)) + return Op1; + + // A | (A & ?) = A + if (match(Op1, m_And(m_Value(A), m_Value(B))) && + (A == Op0 || B == Op0)) + return Op0; + + // ~(A & ?) | A = -1 + if (match(Op0, m_Not(m_And(m_Value(A), m_Value(B)))) && + (A == Op1 || B == Op1)) + return Constant::getAllOnesValue(Op1->getType()); + + // A | ~(A & ?) = -1 + if (match(Op1, m_Not(m_And(m_Value(A), m_Value(B)))) && + (A == Op0 || B == Op0)) + return Constant::getAllOnesValue(Op0->getType()); + + // Try some generic simplifications for associative operations. + if (Value *V = SimplifyAssociativeBinOp(Instruction::Or, Op0, Op1, Q, + MaxRecurse)) + return V; + + // Or distributes over And. Try some generic simplifications based on this. + if (Value *V = ExpandBinOp(Instruction::Or, Op0, Op1, Instruction::And, Q, + MaxRecurse)) + return V; + + // And distributes over Or. Try some generic simplifications based on this. + if (Value *V = FactorizeBinOp(Instruction::Or, Op0, Op1, Instruction::And, + Q, MaxRecurse)) + return V; + + // If the operation is with the result of a select instruction, check whether + // operating on either branch of the select always yields the same value. + if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1)) + if (Value *V = ThreadBinOpOverSelect(Instruction::Or, Op0, Op1, Q, + MaxRecurse)) + return V; + + // If the operation is with the result of a phi instruction, check whether + // operating on all incoming values of the phi always yields the same value. + if (isa<PHINode>(Op0) || isa<PHINode>(Op1)) + if (Value *V = ThreadBinOpOverPHI(Instruction::Or, Op0, Op1, Q, MaxRecurse)) + return V; + + return 0; +} + +Value *llvm::SimplifyOrInst(Value *Op0, Value *Op1, const TargetData *TD, + const TargetLibraryInfo *TLI, + const DominatorTree *DT) { + return ::SimplifyOrInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit); +} + +/// SimplifyXorInst - Given operands for a Xor, see if we can +/// fold the result. If not, this returns null. +static Value *SimplifyXorInst(Value *Op0, Value *Op1, const Query &Q, + unsigned MaxRecurse) { + if (Constant *CLHS = dyn_cast<Constant>(Op0)) { + if (Constant *CRHS = dyn_cast<Constant>(Op1)) { + Constant *Ops[] = { CLHS, CRHS }; + return ConstantFoldInstOperands(Instruction::Xor, CLHS->getType(), + Ops, Q.TD, Q.TLI); + } + + // Canonicalize the constant to the RHS. + std::swap(Op0, Op1); + } + + // A ^ undef -> undef + if (match(Op1, m_Undef())) + return Op1; + + // A ^ 0 = A + if (match(Op1, m_Zero())) + return Op0; + + // A ^ A = 0 + if (Op0 == Op1) + return Constant::getNullValue(Op0->getType()); + + // A ^ ~A = ~A ^ A = -1 + if (match(Op0, m_Not(m_Specific(Op1))) || + match(Op1, m_Not(m_Specific(Op0)))) + return Constant::getAllOnesValue(Op0->getType()); + + // Try some generic simplifications for associative operations. + if (Value *V = SimplifyAssociativeBinOp(Instruction::Xor, Op0, Op1, Q, + MaxRecurse)) + return V; + + // And distributes over Xor. Try some generic simplifications based on this. + if (Value *V = FactorizeBinOp(Instruction::Xor, Op0, Op1, Instruction::And, + Q, MaxRecurse)) + return V; + + // Threading Xor over selects and phi nodes is pointless, so don't bother. + // Threading over the select in "A ^ select(cond, B, C)" means evaluating + // "A^B" and "A^C" and seeing if they are equal; but they are equal if and + // only if B and C are equal. If B and C are equal then (since we assume + // that operands have already been simplified) "select(cond, B, C)" should + // have been simplified to the common value of B and C already. Analysing + // "A^B" and "A^C" thus gains nothing, but costs compile time. Similarly + // for threading over phi nodes. + + return 0; +} + +Value *llvm::SimplifyXorInst(Value *Op0, Value *Op1, const TargetData *TD, + const TargetLibraryInfo *TLI, + const DominatorTree *DT) { + return ::SimplifyXorInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit); +} + +static Type *GetCompareTy(Value *Op) { + return CmpInst::makeCmpResultType(Op->getType()); +} + +/// ExtractEquivalentCondition - Rummage around inside V looking for something +/// equivalent to the comparison "LHS Pred RHS". Return such a value if found, +/// otherwise return null. Helper function for analyzing max/min idioms. +static Value *ExtractEquivalentCondition(Value *V, CmpInst::Predicate Pred, + Value *LHS, Value *RHS) { + SelectInst *SI = dyn_cast<SelectInst>(V); + if (!SI) + return 0; + CmpInst *Cmp = dyn_cast<CmpInst>(SI->getCondition()); + if (!Cmp) + return 0; + Value *CmpLHS = Cmp->getOperand(0), *CmpRHS = Cmp->getOperand(1); + if (Pred == Cmp->getPredicate() && LHS == CmpLHS && RHS == CmpRHS) + return Cmp; + if (Pred == CmpInst::getSwappedPredicate(Cmp->getPredicate()) && + LHS == CmpRHS && RHS == CmpLHS) + return Cmp; + return 0; +} + +static Constant *computePointerICmp(const TargetData &TD, + CmpInst::Predicate Pred, + Value *LHS, Value *RHS) { + // We can only fold certain predicates on pointer comparisons. + switch (Pred) { + default: + return 0; + + // Equality comaprisons are easy to fold. + case CmpInst::ICMP_EQ: + case CmpInst::ICMP_NE: + break; + + // We can only handle unsigned relational comparisons because 'inbounds' on + // a GEP only protects against unsigned wrapping. + case CmpInst::ICMP_UGT: + case CmpInst::ICMP_UGE: + case CmpInst::ICMP_ULT: + case CmpInst::ICMP_ULE: + // However, we have to switch them to their signed variants to handle + // negative indices from the base pointer. + Pred = ICmpInst::getSignedPredicate(Pred); + break; + } + + Constant *LHSOffset = stripAndComputeConstantOffsets(TD, LHS); + if (!LHSOffset) + return 0; + Constant *RHSOffset = stripAndComputeConstantOffsets(TD, RHS); + if (!RHSOffset) + return 0; + + // If LHS and RHS are not related via constant offsets to the same base + // value, there is nothing we can do here. + if (LHS != RHS) + return 0; + + return ConstantExpr::getICmp(Pred, LHSOffset, RHSOffset); +} + +/// SimplifyICmpInst - Given operands for an ICmpInst, see if we can +/// fold the result. If not, this returns null. +static Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS, + const Query &Q, unsigned MaxRecurse) { + CmpInst::Predicate Pred = (CmpInst::Predicate)Predicate; + assert(CmpInst::isIntPredicate(Pred) && "Not an integer compare!"); + + if (Constant *CLHS = dyn_cast<Constant>(LHS)) { + if (Constant *CRHS = dyn_cast<Constant>(RHS)) + return ConstantFoldCompareInstOperands(Pred, CLHS, CRHS, Q.TD, Q.TLI); + + // If we have a constant, make sure it is on the RHS. + std::swap(LHS, RHS); + Pred = CmpInst::getSwappedPredicate(Pred); + } + + Type *ITy = GetCompareTy(LHS); // The return type. + Type *OpTy = LHS->getType(); // The operand type. + + // icmp X, X -> true/false + // X icmp undef -> true/false. For example, icmp ugt %X, undef -> false + // because X could be 0. + if (LHS == RHS || isa<UndefValue>(RHS)) + return ConstantInt::get(ITy, CmpInst::isTrueWhenEqual(Pred)); + + // Special case logic when the operands have i1 type. + if (OpTy->getScalarType()->isIntegerTy(1)) { + switch (Pred) { + default: break; + case ICmpInst::ICMP_EQ: + // X == 1 -> X + if (match(RHS, m_One())) + return LHS; + break; + case ICmpInst::ICMP_NE: + // X != 0 -> X + if (match(RHS, m_Zero())) + return LHS; + break; + case ICmpInst::ICMP_UGT: + // X >u 0 -> X + if (match(RHS, m_Zero())) + return LHS; + break; + case ICmpInst::ICMP_UGE: + // X >=u 1 -> X + if (match(RHS, m_One())) + return LHS; + break; + case ICmpInst::ICMP_SLT: + // X <s 0 -> X + if (match(RHS, m_Zero())) + return LHS; + break; + case ICmpInst::ICMP_SLE: + // X <=s -1 -> X + if (match(RHS, m_One())) + return LHS; + break; + } + } + + // icmp <object*>, <object*/null> - Different identified objects have + // different addresses (unless null), and what's more the address of an + // identified local is never equal to another argument (again, barring null). + // Note that generalizing to the case where LHS is a global variable address + // or null is pointless, since if both LHS and RHS are constants then we + // already constant folded the compare, and if only one of them is then we + // moved it to RHS already. + Value *LHSPtr = LHS->stripPointerCasts(); + Value *RHSPtr = RHS->stripPointerCasts(); + if (LHSPtr == RHSPtr) + return ConstantInt::get(ITy, CmpInst::isTrueWhenEqual(Pred)); + + // Be more aggressive about stripping pointer adjustments when checking a + // comparison of an alloca address to another object. We can rip off all + // inbounds GEP operations, even if they are variable. + LHSPtr = LHSPtr->stripInBoundsOffsets(); + if (llvm::isIdentifiedObject(LHSPtr)) { + RHSPtr = RHSPtr->stripInBoundsOffsets(); + if (llvm::isKnownNonNull(LHSPtr) || llvm::isKnownNonNull(RHSPtr)) { + // If both sides are different identified objects, they aren't equal + // unless they're null. + if (LHSPtr != RHSPtr && llvm::isIdentifiedObject(RHSPtr) && + Pred == CmpInst::ICMP_EQ) + return ConstantInt::get(ITy, false); + + // A local identified object (alloca or noalias call) can't equal any + // incoming argument, unless they're both null. + if (isa<Instruction>(LHSPtr) && isa<Argument>(RHSPtr) && + Pred == CmpInst::ICMP_EQ) + return ConstantInt::get(ITy, false); + } + + // Assume that the constant null is on the right. + if (llvm::isKnownNonNull(LHSPtr) && isa<ConstantPointerNull>(RHSPtr)) { + if (Pred == CmpInst::ICMP_EQ) + return ConstantInt::get(ITy, false); + else if (Pred == CmpInst::ICMP_NE) + return ConstantInt::get(ITy, true); + } + } else if (isa<Argument>(LHSPtr)) { + RHSPtr = RHSPtr->stripInBoundsOffsets(); + // An alloca can't be equal to an argument. + if (isa<AllocaInst>(RHSPtr)) { + if (Pred == CmpInst::ICMP_EQ) + return ConstantInt::get(ITy, false); + else if (Pred == CmpInst::ICMP_NE) + return ConstantInt::get(ITy, true); + } + } + + // If we are comparing with zero then try hard since this is a common case. + if (match(RHS, m_Zero())) { + bool LHSKnownNonNegative, LHSKnownNegative; + switch (Pred) { + default: llvm_unreachable("Unknown ICmp predicate!"); + case ICmpInst::ICMP_ULT: + return getFalse(ITy); + case ICmpInst::ICMP_UGE: + return getTrue(ITy); + case ICmpInst::ICMP_EQ: + case ICmpInst::ICMP_ULE: + if (isKnownNonZero(LHS, Q.TD)) + return getFalse(ITy); + break; + case ICmpInst::ICMP_NE: + case ICmpInst::ICMP_UGT: + if (isKnownNonZero(LHS, Q.TD)) + return getTrue(ITy); + break; + case ICmpInst::ICMP_SLT: + ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, Q.TD); + if (LHSKnownNegative) + return getTrue(ITy); + if (LHSKnownNonNegative) + return getFalse(ITy); + break; + case ICmpInst::ICMP_SLE: + ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, Q.TD); + if (LHSKnownNegative) + return getTrue(ITy); + if (LHSKnownNonNegative && isKnownNonZero(LHS, Q.TD)) + return getFalse(ITy); + break; + case ICmpInst::ICMP_SGE: + ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, Q.TD); + if (LHSKnownNegative) + return getFalse(ITy); + if (LHSKnownNonNegative) + return getTrue(ITy); + break; + case ICmpInst::ICMP_SGT: + ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, Q.TD); + if (LHSKnownNegative) + return getFalse(ITy); + if (LHSKnownNonNegative && isKnownNonZero(LHS, Q.TD)) + return getTrue(ITy); + break; + } + } + + // See if we are doing a comparison with a constant integer. + if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) { + // Rule out tautological comparisons (eg., ult 0 or uge 0). + ConstantRange RHS_CR = ICmpInst::makeConstantRange(Pred, CI->getValue()); + if (RHS_CR.isEmptySet()) + return ConstantInt::getFalse(CI->getContext()); + if (RHS_CR.isFullSet()) + return ConstantInt::getTrue(CI->getContext()); + + // Many binary operators with constant RHS have easy to compute constant + // range. Use them to check whether the comparison is a tautology. + uint32_t Width = CI->getBitWidth(); + APInt Lower = APInt(Width, 0); + APInt Upper = APInt(Width, 0); + ConstantInt *CI2; + if (match(LHS, m_URem(m_Value(), m_ConstantInt(CI2)))) { + // 'urem x, CI2' produces [0, CI2). + Upper = CI2->getValue(); + } else if (match(LHS, m_SRem(m_Value(), m_ConstantInt(CI2)))) { + // 'srem x, CI2' produces (-|CI2|, |CI2|). + Upper = CI2->getValue().abs(); + Lower = (-Upper) + 1; + } else if (match(LHS, m_UDiv(m_ConstantInt(CI2), m_Value()))) { + // 'udiv CI2, x' produces [0, CI2]. + Upper = CI2->getValue() + 1; + } else if (match(LHS, m_UDiv(m_Value(), m_ConstantInt(CI2)))) { + // 'udiv x, CI2' produces [0, UINT_MAX / CI2]. + APInt NegOne = APInt::getAllOnesValue(Width); + if (!CI2->isZero()) + Upper = NegOne.udiv(CI2->getValue()) + 1; + } else if (match(LHS, m_SDiv(m_Value(), m_ConstantInt(CI2)))) { + // 'sdiv x, CI2' produces [INT_MIN / CI2, INT_MAX / CI2]. + APInt IntMin = APInt::getSignedMinValue(Width); + APInt IntMax = APInt::getSignedMaxValue(Width); + APInt Val = CI2->getValue().abs(); + if (!Val.isMinValue()) { + Lower = IntMin.sdiv(Val); + Upper = IntMax.sdiv(Val) + 1; + } + } else if (match(LHS, m_LShr(m_Value(), m_ConstantInt(CI2)))) { + // 'lshr x, CI2' produces [0, UINT_MAX >> CI2]. + APInt NegOne = APInt::getAllOnesValue(Width); + if (CI2->getValue().ult(Width)) + Upper = NegOne.lshr(CI2->getValue()) + 1; + } else if (match(LHS, m_AShr(m_Value(), m_ConstantInt(CI2)))) { + // 'ashr x, CI2' produces [INT_MIN >> CI2, INT_MAX >> CI2]. + APInt IntMin = APInt::getSignedMinValue(Width); + APInt IntMax = APInt::getSignedMaxValue(Width); + if (CI2->getValue().ult(Width)) { + Lower = IntMin.ashr(CI2->getValue()); + Upper = IntMax.ashr(CI2->getValue()) + 1; + } + } else if (match(LHS, m_Or(m_Value(), m_ConstantInt(CI2)))) { + // 'or x, CI2' produces [CI2, UINT_MAX]. + Lower = CI2->getValue(); + } else if (match(LHS, m_And(m_Value(), m_ConstantInt(CI2)))) { + // 'and x, CI2' produces [0, CI2]. + Upper = CI2->getValue() + 1; + } + if (Lower != Upper) { + ConstantRange LHS_CR = ConstantRange(Lower, Upper); + if (RHS_CR.contains(LHS_CR)) + return ConstantInt::getTrue(RHS->getContext()); + if (RHS_CR.inverse().contains(LHS_CR)) + return ConstantInt::getFalse(RHS->getContext()); + } + } + + // Compare of cast, for example (zext X) != 0 -> X != 0 + if (isa<CastInst>(LHS) && (isa<Constant>(RHS) || isa<CastInst>(RHS))) { + Instruction *LI = cast<CastInst>(LHS); + Value *SrcOp = LI->getOperand(0); + Type *SrcTy = SrcOp->getType(); + Type *DstTy = LI->getType(); + + // Turn icmp (ptrtoint x), (ptrtoint/constant) into a compare of the input + // if the integer type is the same size as the pointer type. + if (MaxRecurse && Q.TD && isa<PtrToIntInst>(LI) && + Q.TD->getPointerSizeInBits() == DstTy->getPrimitiveSizeInBits()) { + if (Constant *RHSC = dyn_cast<Constant>(RHS)) { + // Transfer the cast to the constant. + if (Value *V = SimplifyICmpInst(Pred, SrcOp, + ConstantExpr::getIntToPtr(RHSC, SrcTy), + Q, MaxRecurse-1)) + return V; + } else if (PtrToIntInst *RI = dyn_cast<PtrToIntInst>(RHS)) { + if (RI->getOperand(0)->getType() == SrcTy) + // Compare without the cast. + if (Value *V = SimplifyICmpInst(Pred, SrcOp, RI->getOperand(0), + Q, MaxRecurse-1)) + return V; + } + } + + if (isa<ZExtInst>(LHS)) { + // Turn icmp (zext X), (zext Y) into a compare of X and Y if they have the + // same type. + if (ZExtInst *RI = dyn_cast<ZExtInst>(RHS)) { + if (MaxRecurse && SrcTy == RI->getOperand(0)->getType()) + // Compare X and Y. Note that signed predicates become unsigned. + if (Value *V = SimplifyICmpInst(ICmpInst::getUnsignedPredicate(Pred), + SrcOp, RI->getOperand(0), Q, + MaxRecurse-1)) + return V; + } + // Turn icmp (zext X), Cst into a compare of X and Cst if Cst is extended + // too. If not, then try to deduce the result of the comparison. + else if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) { + // Compute the constant that would happen if we truncated to SrcTy then + // reextended to DstTy. + Constant *Trunc = ConstantExpr::getTrunc(CI, SrcTy); + Constant *RExt = ConstantExpr::getCast(CastInst::ZExt, Trunc, DstTy); + + // If the re-extended constant didn't change then this is effectively + // also a case of comparing two zero-extended values. + if (RExt == CI && MaxRecurse) + if (Value *V = SimplifyICmpInst(ICmpInst::getUnsignedPredicate(Pred), + SrcOp, Trunc, Q, MaxRecurse-1)) + return V; + + // Otherwise the upper bits of LHS are zero while RHS has a non-zero bit + // there. Use this to work out the result of the comparison. + if (RExt != CI) { + switch (Pred) { + default: llvm_unreachable("Unknown ICmp predicate!"); + // LHS <u RHS. + case ICmpInst::ICMP_EQ: + case ICmpInst::ICMP_UGT: + case ICmpInst::ICMP_UGE: + return ConstantInt::getFalse(CI->getContext()); + + case ICmpInst::ICMP_NE: + case ICmpInst::ICMP_ULT: + case ICmpInst::ICMP_ULE: + return ConstantInt::getTrue(CI->getContext()); + + // LHS is non-negative. If RHS is negative then LHS >s LHS. If RHS + // is non-negative then LHS <s RHS. + case ICmpInst::ICMP_SGT: + case ICmpInst::ICMP_SGE: + return CI->getValue().isNegative() ? + ConstantInt::getTrue(CI->getContext()) : + ConstantInt::getFalse(CI->getContext()); + + case ICmpInst::ICMP_SLT: + case ICmpInst::ICMP_SLE: + return CI->getValue().isNegative() ? + ConstantInt::getFalse(CI->getContext()) : + ConstantInt::getTrue(CI->getContext()); + } + } + } + } + + if (isa<SExtInst>(LHS)) { + // Turn icmp (sext X), (sext Y) into a compare of X and Y if they have the + // same type. + if (SExtInst *RI = dyn_cast<SExtInst>(RHS)) { + if (MaxRecurse && SrcTy == RI->getOperand(0)->getType()) + // Compare X and Y. Note that the predicate does not change. + if (Value *V = SimplifyICmpInst(Pred, SrcOp, RI->getOperand(0), + Q, MaxRecurse-1)) + return V; + } + // Turn icmp (sext X), Cst into a compare of X and Cst if Cst is extended + // too. If not, then try to deduce the result of the comparison. + else if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) { + // Compute the constant that would happen if we truncated to SrcTy then + // reextended to DstTy. + Constant *Trunc = ConstantExpr::getTrunc(CI, SrcTy); + Constant *RExt = ConstantExpr::getCast(CastInst::SExt, Trunc, DstTy); + + // If the re-extended constant didn't change then this is effectively + // also a case of comparing two sign-extended values. + if (RExt == CI && MaxRecurse) + if (Value *V = SimplifyICmpInst(Pred, SrcOp, Trunc, Q, MaxRecurse-1)) + return V; + + // Otherwise the upper bits of LHS are all equal, while RHS has varying + // bits there. Use this to work out the result of the comparison. + if (RExt != CI) { + switch (Pred) { + default: llvm_unreachable("Unknown ICmp predicate!"); + case ICmpInst::ICMP_EQ: + return ConstantInt::getFalse(CI->getContext()); + case ICmpInst::ICMP_NE: + return ConstantInt::getTrue(CI->getContext()); + + // If RHS is non-negative then LHS <s RHS. If RHS is negative then + // LHS >s RHS. + case ICmpInst::ICMP_SGT: + case ICmpInst::ICMP_SGE: + return CI->getValue().isNegative() ? + ConstantInt::getTrue(CI->getContext()) : + ConstantInt::getFalse(CI->getContext()); + case ICmpInst::ICMP_SLT: + case ICmpInst::ICMP_SLE: + return CI->getValue().isNegative() ? + ConstantInt::getFalse(CI->getContext()) : + ConstantInt::getTrue(CI->getContext()); + + // If LHS is non-negative then LHS <u RHS. If LHS is negative then + // LHS >u RHS. + case ICmpInst::ICMP_UGT: + case ICmpInst::ICMP_UGE: + // Comparison is true iff the LHS <s 0. + if (MaxRecurse) + if (Value *V = SimplifyICmpInst(ICmpInst::ICMP_SLT, SrcOp, + Constant::getNullValue(SrcTy), + Q, MaxRecurse-1)) + return V; + break; + case ICmpInst::ICMP_ULT: + case ICmpInst::ICMP_ULE: + // Comparison is true iff the LHS >=s 0. + if (MaxRecurse) + if (Value *V = SimplifyICmpInst(ICmpInst::ICMP_SGE, SrcOp, + Constant::getNullValue(SrcTy), + Q, MaxRecurse-1)) + return V; + break; + } + } + } + } + } + + // Special logic for binary operators. + BinaryOperator *LBO = dyn_cast<BinaryOperator>(LHS); + BinaryOperator *RBO = dyn_cast<BinaryOperator>(RHS); + if (MaxRecurse && (LBO || RBO)) { + // Analyze the case when either LHS or RHS is an add instruction. + Value *A = 0, *B = 0, *C = 0, *D = 0; + // LHS = A + B (or A and B are null); RHS = C + D (or C and D are null). + bool NoLHSWrapProblem = false, NoRHSWrapProblem = false; + if (LBO && LBO->getOpcode() == Instruction::Add) { + A = LBO->getOperand(0); B = LBO->getOperand(1); + NoLHSWrapProblem = ICmpInst::isEquality(Pred) || + (CmpInst::isUnsigned(Pred) && LBO->hasNoUnsignedWrap()) || + (CmpInst::isSigned(Pred) && LBO->hasNoSignedWrap()); + } + if (RBO && RBO->getOpcode() == Instruction::Add) { + C = RBO->getOperand(0); D = RBO->getOperand(1); + NoRHSWrapProblem = ICmpInst::isEquality(Pred) || + (CmpInst::isUnsigned(Pred) && RBO->hasNoUnsignedWrap()) || + (CmpInst::isSigned(Pred) && RBO->hasNoSignedWrap()); + } + + // icmp (X+Y), X -> icmp Y, 0 for equalities or if there is no overflow. + if ((A == RHS || B == RHS) && NoLHSWrapProblem) + if (Value *V = SimplifyICmpInst(Pred, A == RHS ? B : A, + Constant::getNullValue(RHS->getType()), + Q, MaxRecurse-1)) + return V; + + // icmp X, (X+Y) -> icmp 0, Y for equalities or if there is no overflow. + if ((C == LHS || D == LHS) && NoRHSWrapProblem) + if (Value *V = SimplifyICmpInst(Pred, + Constant::getNullValue(LHS->getType()), + C == LHS ? D : C, Q, MaxRecurse-1)) + return V; + + // icmp (X+Y), (X+Z) -> icmp Y,Z for equalities or if there is no overflow. + if (A && C && (A == C || A == D || B == C || B == D) && + NoLHSWrapProblem && NoRHSWrapProblem) { + // Determine Y and Z in the form icmp (X+Y), (X+Z). + Value *Y = (A == C || A == D) ? B : A; + Value *Z = (C == A || C == B) ? D : C; + if (Value *V = SimplifyICmpInst(Pred, Y, Z, Q, MaxRecurse-1)) + return V; + } + } + + if (LBO && match(LBO, m_URem(m_Value(), m_Specific(RHS)))) { + bool KnownNonNegative, KnownNegative; + switch (Pred) { + default: + break; + case ICmpInst::ICMP_SGT: + case ICmpInst::ICMP_SGE: + ComputeSignBit(LHS, KnownNonNegative, KnownNegative, Q.TD); + if (!KnownNonNegative) + break; + // fall-through + case ICmpInst::ICMP_EQ: + case ICmpInst::ICMP_UGT: + case ICmpInst::ICMP_UGE: + return getFalse(ITy); + case ICmpInst::ICMP_SLT: + case ICmpInst::ICMP_SLE: + ComputeSignBit(LHS, KnownNonNegative, KnownNegative, Q.TD); + if (!KnownNonNegative) + break; + // fall-through + case ICmpInst::ICMP_NE: + case ICmpInst::ICMP_ULT: + case ICmpInst::ICMP_ULE: + return getTrue(ITy); + } + } + if (RBO && match(RBO, m_URem(m_Value(), m_Specific(LHS)))) { + bool KnownNonNegative, KnownNegative; + switch (Pred) { + default: + break; + case ICmpInst::ICMP_SGT: + case ICmpInst::ICMP_SGE: + ComputeSignBit(RHS, KnownNonNegative, KnownNegative, Q.TD); + if (!KnownNonNegative) + break; + // fall-through + case ICmpInst::ICMP_NE: + case ICmpInst::ICMP_UGT: + case ICmpInst::ICMP_UGE: + return getTrue(ITy); + case ICmpInst::ICMP_SLT: + case ICmpInst::ICMP_SLE: + ComputeSignBit(RHS, KnownNonNegative, KnownNegative, Q.TD); + if (!KnownNonNegative) + break; + // fall-through + case ICmpInst::ICMP_EQ: + case ICmpInst::ICMP_ULT: + case ICmpInst::ICMP_ULE: + return getFalse(ITy); + } + } + + // x udiv y <=u x. + if (LBO && match(LBO, m_UDiv(m_Specific(RHS), m_Value()))) { + // icmp pred (X /u Y), X + if (Pred == ICmpInst::ICMP_UGT) + return getFalse(ITy); + if (Pred == ICmpInst::ICMP_ULE) + return getTrue(ITy); + } + + if (MaxRecurse && LBO && RBO && LBO->getOpcode() == RBO->getOpcode() && + LBO->getOperand(1) == RBO->getOperand(1)) { + switch (LBO->getOpcode()) { + default: break; + case Instruction::UDiv: + case Instruction::LShr: + if (ICmpInst::isSigned(Pred)) + break; + // fall-through + case Instruction::SDiv: + case Instruction::AShr: + if (!LBO->isExact() || !RBO->isExact()) + break; + if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0), + RBO->getOperand(0), Q, MaxRecurse-1)) + return V; + break; + case Instruction::Shl: { + bool NUW = LBO->hasNoUnsignedWrap() && RBO->hasNoUnsignedWrap(); + bool NSW = LBO->hasNoSignedWrap() && RBO->hasNoSignedWrap(); + if (!NUW && !NSW) + break; + if (!NSW && ICmpInst::isSigned(Pred)) + break; + if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0), + RBO->getOperand(0), Q, MaxRecurse-1)) + return V; + break; + } + } + } + + // Simplify comparisons involving max/min. + Value *A, *B; + CmpInst::Predicate P = CmpInst::BAD_ICMP_PREDICATE; + CmpInst::Predicate EqP; // Chosen so that "A == max/min(A,B)" iff "A EqP B". + + // Signed variants on "max(a,b)>=a -> true". + if (match(LHS, m_SMax(m_Value(A), m_Value(B))) && (A == RHS || B == RHS)) { + if (A != RHS) std::swap(A, B); // smax(A, B) pred A. + EqP = CmpInst::ICMP_SGE; // "A == smax(A, B)" iff "A sge B". + // We analyze this as smax(A, B) pred A. + P = Pred; + } else if (match(RHS, m_SMax(m_Value(A), m_Value(B))) && + (A == LHS || B == LHS)) { + if (A != LHS) std::swap(A, B); // A pred smax(A, B). + EqP = CmpInst::ICMP_SGE; // "A == smax(A, B)" iff "A sge B". + // We analyze this as smax(A, B) swapped-pred A. + P = CmpInst::getSwappedPredicate(Pred); + } else if (match(LHS, m_SMin(m_Value(A), m_Value(B))) && + (A == RHS || B == RHS)) { + if (A != RHS) std::swap(A, B); // smin(A, B) pred A. + EqP = CmpInst::ICMP_SLE; // "A == smin(A, B)" iff "A sle B". + // We analyze this as smax(-A, -B) swapped-pred -A. + // Note that we do not need to actually form -A or -B thanks to EqP. + P = CmpInst::getSwappedPredicate(Pred); + } else if (match(RHS, m_SMin(m_Value(A), m_Value(B))) && + (A == LHS || B == LHS)) { + if (A != LHS) std::swap(A, B); // A pred smin(A, B). + EqP = CmpInst::ICMP_SLE; // "A == smin(A, B)" iff "A sle B". + // We analyze this as smax(-A, -B) pred -A. + // Note that we do not need to actually form -A or -B thanks to EqP. + P = Pred; + } + if (P != CmpInst::BAD_ICMP_PREDICATE) { + // Cases correspond to "max(A, B) p A". + switch (P) { + default: + break; + case CmpInst::ICMP_EQ: + case CmpInst::ICMP_SLE: + // Equivalent to "A EqP B". This may be the same as the condition tested + // in the max/min; if so, we can just return that. + if (Value *V = ExtractEquivalentCondition(LHS, EqP, A, B)) + return V; + if (Value *V = ExtractEquivalentCondition(RHS, EqP, A, B)) + return V; + // Otherwise, see if "A EqP B" simplifies. + if (MaxRecurse) + if (Value *V = SimplifyICmpInst(EqP, A, B, Q, MaxRecurse-1)) + return V; + break; + case CmpInst::ICMP_NE: + case CmpInst::ICMP_SGT: { + CmpInst::Predicate InvEqP = CmpInst::getInversePredicate(EqP); + // Equivalent to "A InvEqP B". This may be the same as the condition + // tested in the max/min; if so, we can just return that. + if (Value *V = ExtractEquivalentCondition(LHS, InvEqP, A, B)) + return V; + if (Value *V = ExtractEquivalentCondition(RHS, InvEqP, A, B)) + return V; + // Otherwise, see if "A InvEqP B" simplifies. + if (MaxRecurse) + if (Value *V = SimplifyICmpInst(InvEqP, A, B, Q, MaxRecurse-1)) + return V; + break; + } + case CmpInst::ICMP_SGE: + // Always true. + return getTrue(ITy); + case CmpInst::ICMP_SLT: + // Always false. + return getFalse(ITy); + } + } + + // Unsigned variants on "max(a,b)>=a -> true". + P = CmpInst::BAD_ICMP_PREDICATE; + if (match(LHS, m_UMax(m_Value(A), m_Value(B))) && (A == RHS || B == RHS)) { + if (A != RHS) std::swap(A, B); // umax(A, B) pred A. + EqP = CmpInst::ICMP_UGE; // "A == umax(A, B)" iff "A uge B". + // We analyze this as umax(A, B) pred A. + P = Pred; + } else if (match(RHS, m_UMax(m_Value(A), m_Value(B))) && + (A == LHS || B == LHS)) { + if (A != LHS) std::swap(A, B); // A pred umax(A, B). + EqP = CmpInst::ICMP_UGE; // "A == umax(A, B)" iff "A uge B". + // We analyze this as umax(A, B) swapped-pred A. + P = CmpInst::getSwappedPredicate(Pred); + } else if (match(LHS, m_UMin(m_Value(A), m_Value(B))) && + (A == RHS || B == RHS)) { + if (A != RHS) std::swap(A, B); // umin(A, B) pred A. + EqP = CmpInst::ICMP_ULE; // "A == umin(A, B)" iff "A ule B". + // We analyze this as umax(-A, -B) swapped-pred -A. + // Note that we do not need to actually form -A or -B thanks to EqP. + P = CmpInst::getSwappedPredicate(Pred); + } else if (match(RHS, m_UMin(m_Value(A), m_Value(B))) && + (A == LHS || B == LHS)) { + if (A != LHS) std::swap(A, B); // A pred umin(A, B). + EqP = CmpInst::ICMP_ULE; // "A == umin(A, B)" iff "A ule B". + // We analyze this as umax(-A, -B) pred -A. + // Note that we do not need to actually form -A or -B thanks to EqP. + P = Pred; + } + if (P != CmpInst::BAD_ICMP_PREDICATE) { + // Cases correspond to "max(A, B) p A". + switch (P) { + default: + break; + case CmpInst::ICMP_EQ: + case CmpInst::ICMP_ULE: + // Equivalent to "A EqP B". This may be the same as the condition tested + // in the max/min; if so, we can just return that. + if (Value *V = ExtractEquivalentCondition(LHS, EqP, A, B)) + return V; + if (Value *V = ExtractEquivalentCondition(RHS, EqP, A, B)) + return V; + // Otherwise, see if "A EqP B" simplifies. + if (MaxRecurse) + if (Value *V = SimplifyICmpInst(EqP, A, B, Q, MaxRecurse-1)) + return V; + break; + case CmpInst::ICMP_NE: + case CmpInst::ICMP_UGT: { + CmpInst::Predicate InvEqP = CmpInst::getInversePredicate(EqP); + // Equivalent to "A InvEqP B". This may be the same as the condition + // tested in the max/min; if so, we can just return that. + if (Value *V = ExtractEquivalentCondition(LHS, InvEqP, A, B)) + return V; + if (Value *V = ExtractEquivalentCondition(RHS, InvEqP, A, B)) + return V; + // Otherwise, see if "A InvEqP B" simplifies. + if (MaxRecurse) + if (Value *V = SimplifyICmpInst(InvEqP, A, B, Q, MaxRecurse-1)) + return V; + break; + } + case CmpInst::ICMP_UGE: + // Always true. + return getTrue(ITy); + case CmpInst::ICMP_ULT: + // Always false. + return getFalse(ITy); + } + } + + // Variants on "max(x,y) >= min(x,z)". + Value *C, *D; + if (match(LHS, m_SMax(m_Value(A), m_Value(B))) && + match(RHS, m_SMin(m_Value(C), m_Value(D))) && + (A == C || A == D || B == C || B == D)) { + // max(x, ?) pred min(x, ?). + if (Pred == CmpInst::ICMP_SGE) + // Always true. + return getTrue(ITy); + if (Pred == CmpInst::ICMP_SLT) + // Always false. + return getFalse(ITy); + } else if (match(LHS, m_SMin(m_Value(A), m_Value(B))) && + match(RHS, m_SMax(m_Value(C), m_Value(D))) && + (A == C || A == D || B == C || B == D)) { + // min(x, ?) pred max(x, ?). + if (Pred == CmpInst::ICMP_SLE) + // Always true. + return getTrue(ITy); + if (Pred == CmpInst::ICMP_SGT) + // Always false. + return getFalse(ITy); + } else if (match(LHS, m_UMax(m_Value(A), m_Value(B))) && + match(RHS, m_UMin(m_Value(C), m_Value(D))) && + (A == C || A == D || B == C || B == D)) { + // max(x, ?) pred min(x, ?). + if (Pred == CmpInst::ICMP_UGE) + // Always true. + return getTrue(ITy); + if (Pred == CmpInst::ICMP_ULT) + // Always false. + return getFalse(ITy); + } else if (match(LHS, m_UMin(m_Value(A), m_Value(B))) && + match(RHS, m_UMax(m_Value(C), m_Value(D))) && + (A == C || A == D || B == C || B == D)) { + // min(x, ?) pred max(x, ?). + if (Pred == CmpInst::ICMP_ULE) + // Always true. + return getTrue(ITy); + if (Pred == CmpInst::ICMP_UGT) + // Always false. + return getFalse(ITy); + } + + // Simplify comparisons of related pointers using a powerful, recursive + // GEP-walk when we have target data available.. + if (Q.TD && LHS->getType()->isPointerTy() && RHS->getType()->isPointerTy()) + if (Constant *C = computePointerICmp(*Q.TD, Pred, LHS, RHS)) + return C; + + if (GetElementPtrInst *GLHS = dyn_cast<GetElementPtrInst>(LHS)) { + if (GEPOperator *GRHS = dyn_cast<GEPOperator>(RHS)) { + if (GLHS->getPointerOperand() == GRHS->getPointerOperand() && + GLHS->hasAllConstantIndices() && GRHS->hasAllConstantIndices() && + (ICmpInst::isEquality(Pred) || + (GLHS->isInBounds() && GRHS->isInBounds() && + Pred == ICmpInst::getSignedPredicate(Pred)))) { + // The bases are equal and the indices are constant. Build a constant + // expression GEP with the same indices and a null base pointer to see + // what constant folding can make out of it. + Constant *Null = Constant::getNullValue(GLHS->getPointerOperandType()); + SmallVector<Value *, 4> IndicesLHS(GLHS->idx_begin(), GLHS->idx_end()); + Constant *NewLHS = ConstantExpr::getGetElementPtr(Null, IndicesLHS); + + SmallVector<Value *, 4> IndicesRHS(GRHS->idx_begin(), GRHS->idx_end()); + Constant *NewRHS = ConstantExpr::getGetElementPtr(Null, IndicesRHS); + return ConstantExpr::getICmp(Pred, NewLHS, NewRHS); + } + } + } + + // If the comparison is with the result of a select instruction, check whether + // comparing with either branch of the select always yields the same value. + if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS)) + if (Value *V = ThreadCmpOverSelect(Pred, LHS, RHS, Q, MaxRecurse)) + return V; + + // If the comparison is with the result of a phi instruction, check whether + // doing the compare with each incoming phi value yields a common result. + if (isa<PHINode>(LHS) || isa<PHINode>(RHS)) + if (Value *V = ThreadCmpOverPHI(Pred, LHS, RHS, Q, MaxRecurse)) + return V; + + return 0; +} + +Value *llvm::SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS, + const TargetData *TD, + const TargetLibraryInfo *TLI, + const DominatorTree *DT) { + return ::SimplifyICmpInst(Predicate, LHS, RHS, Query (TD, TLI, DT), + RecursionLimit); +} + +/// SimplifyFCmpInst - Given operands for an FCmpInst, see if we can +/// fold the result. If not, this returns null. +static Value *SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS, + const Query &Q, unsigned MaxRecurse) { + CmpInst::Predicate Pred = (CmpInst::Predicate)Predicate; + assert(CmpInst::isFPPredicate(Pred) && "Not an FP compare!"); + + if (Constant *CLHS = dyn_cast<Constant>(LHS)) { + if (Constant *CRHS = dyn_cast<Constant>(RHS)) + return ConstantFoldCompareInstOperands(Pred, CLHS, CRHS, Q.TD, Q.TLI); + + // If we have a constant, make sure it is on the RHS. + std::swap(LHS, RHS); + Pred = CmpInst::getSwappedPredicate(Pred); + } + + // Fold trivial predicates. + if (Pred == FCmpInst::FCMP_FALSE) + return ConstantInt::get(GetCompareTy(LHS), 0); + if (Pred == FCmpInst::FCMP_TRUE) + return ConstantInt::get(GetCompareTy(LHS), 1); + + if (isa<UndefValue>(RHS)) // fcmp pred X, undef -> undef + return UndefValue::get(GetCompareTy(LHS)); + + // fcmp x,x -> true/false. Not all compares are foldable. + if (LHS == RHS) { + if (CmpInst::isTrueWhenEqual(Pred)) + return ConstantInt::get(GetCompareTy(LHS), 1); + if (CmpInst::isFalseWhenEqual(Pred)) + return ConstantInt::get(GetCompareTy(LHS), 0); + } + + // Handle fcmp with constant RHS + if (Constant *RHSC = dyn_cast<Constant>(RHS)) { + // If the constant is a nan, see if we can fold the comparison based on it. + if (ConstantFP *CFP = dyn_cast<ConstantFP>(RHSC)) { + if (CFP->getValueAPF().isNaN()) { + if (FCmpInst::isOrdered(Pred)) // True "if ordered and foo" + return ConstantInt::getFalse(CFP->getContext()); + assert(FCmpInst::isUnordered(Pred) && + "Comparison must be either ordered or unordered!"); + // True if unordered. + return ConstantInt::getTrue(CFP->getContext()); + } + // Check whether the constant is an infinity. + if (CFP->getValueAPF().isInfinity()) { + if (CFP->getValueAPF().isNegative()) { + switch (Pred) { + case FCmpInst::FCMP_OLT: + // No value is ordered and less than negative infinity. + return ConstantInt::getFalse(CFP->getContext()); + case FCmpInst::FCMP_UGE: + // All values are unordered with or at least negative infinity. + return ConstantInt::getTrue(CFP->getContext()); + default: + break; + } + } else { + switch (Pred) { + case FCmpInst::FCMP_OGT: + // No value is ordered and greater than infinity. + return ConstantInt::getFalse(CFP->getContext()); + case FCmpInst::FCMP_ULE: + // All values are unordered with and at most infinity. + return ConstantInt::getTrue(CFP->getContext()); + default: + break; + } + } + } + } + } + + // If the comparison is with the result of a select instruction, check whether + // comparing with either branch of the select always yields the same value. + if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS)) + if (Value *V = ThreadCmpOverSelect(Pred, LHS, RHS, Q, MaxRecurse)) + return V; + + // If the comparison is with the result of a phi instruction, check whether + // doing the compare with each incoming phi value yields a common result. + if (isa<PHINode>(LHS) || isa<PHINode>(RHS)) + if (Value *V = ThreadCmpOverPHI(Pred, LHS, RHS, Q, MaxRecurse)) + return V; + + return 0; +} + +Value *llvm::SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS, + const TargetData *TD, + const TargetLibraryInfo *TLI, + const DominatorTree *DT) { + return ::SimplifyFCmpInst(Predicate, LHS, RHS, Query (TD, TLI, DT), + RecursionLimit); +} + +/// SimplifySelectInst - Given operands for a SelectInst, see if we can fold +/// the result. If not, this returns null. +static Value *SimplifySelectInst(Value *CondVal, Value *TrueVal, + Value *FalseVal, const Query &Q, + unsigned MaxRecurse) { + // select true, X, Y -> X + // select false, X, Y -> Y + if (ConstantInt *CB = dyn_cast<ConstantInt>(CondVal)) + return CB->getZExtValue() ? TrueVal : FalseVal; + + // select C, X, X -> X + if (TrueVal == FalseVal) + return TrueVal; + + if (isa<UndefValue>(CondVal)) { // select undef, X, Y -> X or Y + if (isa<Constant>(TrueVal)) + return TrueVal; + return FalseVal; + } + if (isa<UndefValue>(TrueVal)) // select C, undef, X -> X + return FalseVal; + if (isa<UndefValue>(FalseVal)) // select C, X, undef -> X + return TrueVal; + + return 0; +} + +Value *llvm::SimplifySelectInst(Value *Cond, Value *TrueVal, Value *FalseVal, + const TargetData *TD, + const TargetLibraryInfo *TLI, + const DominatorTree *DT) { + return ::SimplifySelectInst(Cond, TrueVal, FalseVal, Query (TD, TLI, DT), + RecursionLimit); +} + +/// SimplifyGEPInst - Given operands for an GetElementPtrInst, see if we can +/// fold the result. If not, this returns null. +static Value *SimplifyGEPInst(ArrayRef<Value *> Ops, const Query &Q, unsigned) { + // The type of the GEP pointer operand. + PointerType *PtrTy = dyn_cast<PointerType>(Ops[0]->getType()); + // The GEP pointer operand is not a pointer, it's a vector of pointers. + if (!PtrTy) + return 0; + + // getelementptr P -> P. + if (Ops.size() == 1) + return Ops[0]; + + if (isa<UndefValue>(Ops[0])) { + // Compute the (pointer) type returned by the GEP instruction. + Type *LastType = GetElementPtrInst::getIndexedType(PtrTy, Ops.slice(1)); + Type *GEPTy = PointerType::get(LastType, PtrTy->getAddressSpace()); + return UndefValue::get(GEPTy); + } + + if (Ops.size() == 2) { + // getelementptr P, 0 -> P. + if (ConstantInt *C = dyn_cast<ConstantInt>(Ops[1])) + if (C->isZero()) + return Ops[0]; + // getelementptr P, N -> P if P points to a type of zero size. + if (Q.TD) { + Type *Ty = PtrTy->getElementType(); + if (Ty->isSized() && Q.TD->getTypeAllocSize(Ty) == 0) + return Ops[0]; + } + } + + // Check to see if this is constant foldable. + for (unsigned i = 0, e = Ops.size(); i != e; ++i) + if (!isa<Constant>(Ops[i])) + return 0; + + return ConstantExpr::getGetElementPtr(cast<Constant>(Ops[0]), Ops.slice(1)); +} + +Value *llvm::SimplifyGEPInst(ArrayRef<Value *> Ops, const TargetData *TD, + const TargetLibraryInfo *TLI, + const DominatorTree *DT) { + return ::SimplifyGEPInst(Ops, Query (TD, TLI, DT), RecursionLimit); +} + +/// SimplifyInsertValueInst - Given operands for an InsertValueInst, see if we +/// can fold the result. If not, this returns null. +static Value *SimplifyInsertValueInst(Value *Agg, Value *Val, + ArrayRef<unsigned> Idxs, const Query &Q, + unsigned) { + if (Constant *CAgg = dyn_cast<Constant>(Agg)) + if (Constant *CVal = dyn_cast<Constant>(Val)) + return ConstantFoldInsertValueInstruction(CAgg, CVal, Idxs); + + // insertvalue x, undef, n -> x + if (match(Val, m_Undef())) + return Agg; + + // insertvalue x, (extractvalue y, n), n + if (ExtractValueInst *EV = dyn_cast<ExtractValueInst>(Val)) + if (EV->getAggregateOperand()->getType() == Agg->getType() && + EV->getIndices() == Idxs) { + // insertvalue undef, (extractvalue y, n), n -> y + if (match(Agg, m_Undef())) + return EV->getAggregateOperand(); + + // insertvalue y, (extractvalue y, n), n -> y + if (Agg == EV->getAggregateOperand()) + return Agg; + } + + return 0; +} + +Value *llvm::SimplifyInsertValueInst(Value *Agg, Value *Val, + ArrayRef<unsigned> Idxs, + const TargetData *TD, + const TargetLibraryInfo *TLI, + const DominatorTree *DT) { + return ::SimplifyInsertValueInst(Agg, Val, Idxs, Query (TD, TLI, DT), + RecursionLimit); +} + +/// SimplifyPHINode - See if we can fold the given phi. If not, returns null. +static Value *SimplifyPHINode(PHINode *PN, const Query &Q) { + // If all of the PHI's incoming values are the same then replace the PHI node + // with the common value. + Value *CommonValue = 0; + bool HasUndefInput = false; + for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) { + Value *Incoming = PN->getIncomingValue(i); + // If the incoming value is the phi node itself, it can safely be skipped. + if (Incoming == PN) continue; + if (isa<UndefValue>(Incoming)) { + // Remember that we saw an undef value, but otherwise ignore them. + HasUndefInput = true; + continue; + } + if (CommonValue && Incoming != CommonValue) + return 0; // Not the same, bail out. + CommonValue = Incoming; + } + + // If CommonValue is null then all of the incoming values were either undef or + // equal to the phi node itself. + if (!CommonValue) + return UndefValue::get(PN->getType()); + + // If we have a PHI node like phi(X, undef, X), where X is defined by some + // instruction, we cannot return X as the result of the PHI node unless it + // dominates the PHI block. + if (HasUndefInput) + return ValueDominatesPHI(CommonValue, PN, Q.DT) ? CommonValue : 0; + + return CommonValue; +} + +static Value *SimplifyTruncInst(Value *Op, Type *Ty, const Query &Q, unsigned) { + if (Constant *C = dyn_cast<Constant>(Op)) + return ConstantFoldInstOperands(Instruction::Trunc, Ty, C, Q.TD, Q.TLI); + + return 0; +} + +Value *llvm::SimplifyTruncInst(Value *Op, Type *Ty, const TargetData *TD, + const TargetLibraryInfo *TLI, + const DominatorTree *DT) { + return ::SimplifyTruncInst(Op, Ty, Query (TD, TLI, DT), RecursionLimit); +} + +//=== Helper functions for higher up the class hierarchy. + +/// SimplifyBinOp - Given operands for a BinaryOperator, see if we can +/// fold the result. If not, this returns null. +static Value *SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS, + const Query &Q, unsigned MaxRecurse) { + switch (Opcode) { + case Instruction::Add: + return SimplifyAddInst(LHS, RHS, /*isNSW*/false, /*isNUW*/false, + Q, MaxRecurse); + case Instruction::Sub: + return SimplifySubInst(LHS, RHS, /*isNSW*/false, /*isNUW*/false, + Q, MaxRecurse); + case Instruction::Mul: return SimplifyMulInst (LHS, RHS, Q, MaxRecurse); + case Instruction::SDiv: return SimplifySDivInst(LHS, RHS, Q, MaxRecurse); + case Instruction::UDiv: return SimplifyUDivInst(LHS, RHS, Q, MaxRecurse); + case Instruction::FDiv: return SimplifyFDivInst(LHS, RHS, Q, MaxRecurse); + case Instruction::SRem: return SimplifySRemInst(LHS, RHS, Q, MaxRecurse); + case Instruction::URem: return SimplifyURemInst(LHS, RHS, Q, MaxRecurse); + case Instruction::FRem: return SimplifyFRemInst(LHS, RHS, Q, MaxRecurse); + case Instruction::Shl: + return SimplifyShlInst(LHS, RHS, /*isNSW*/false, /*isNUW*/false, + Q, MaxRecurse); + case Instruction::LShr: + return SimplifyLShrInst(LHS, RHS, /*isExact*/false, Q, MaxRecurse); + case Instruction::AShr: + return SimplifyAShrInst(LHS, RHS, /*isExact*/false, Q, MaxRecurse); + case Instruction::And: return SimplifyAndInst(LHS, RHS, Q, MaxRecurse); + case Instruction::Or: return SimplifyOrInst (LHS, RHS, Q, MaxRecurse); + case Instruction::Xor: return SimplifyXorInst(LHS, RHS, Q, MaxRecurse); + default: + if (Constant *CLHS = dyn_cast<Constant>(LHS)) + if (Constant *CRHS = dyn_cast<Constant>(RHS)) { + Constant *COps[] = {CLHS, CRHS}; + return ConstantFoldInstOperands(Opcode, LHS->getType(), COps, Q.TD, + Q.TLI); + } + + // If the operation is associative, try some generic simplifications. + if (Instruction::isAssociative(Opcode)) + if (Value *V = SimplifyAssociativeBinOp(Opcode, LHS, RHS, Q, MaxRecurse)) + return V; + + // If the operation is with the result of a select instruction check whether + // operating on either branch of the select always yields the same value. + if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS)) + if (Value *V = ThreadBinOpOverSelect(Opcode, LHS, RHS, Q, MaxRecurse)) + return V; + + // If the operation is with the result of a phi instruction, check whether + // operating on all incoming values of the phi always yields the same value. + if (isa<PHINode>(LHS) || isa<PHINode>(RHS)) + if (Value *V = ThreadBinOpOverPHI(Opcode, LHS, RHS, Q, MaxRecurse)) + return V; + + return 0; + } +} + +Value *llvm::SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS, + const TargetData *TD, const TargetLibraryInfo *TLI, + const DominatorTree *DT) { + return ::SimplifyBinOp(Opcode, LHS, RHS, Query (TD, TLI, DT), RecursionLimit); +} + +/// SimplifyCmpInst - Given operands for a CmpInst, see if we can +/// fold the result. +static Value *SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS, + const Query &Q, unsigned MaxRecurse) { + if (CmpInst::isIntPredicate((CmpInst::Predicate)Predicate)) + return SimplifyICmpInst(Predicate, LHS, RHS, Q, MaxRecurse); + return SimplifyFCmpInst(Predicate, LHS, RHS, Q, MaxRecurse); +} + +Value *llvm::SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS, + const TargetData *TD, const TargetLibraryInfo *TLI, + const DominatorTree *DT) { + return ::SimplifyCmpInst(Predicate, LHS, RHS, Query (TD, TLI, DT), + RecursionLimit); +} + +static Value *SimplifyCallInst(CallInst *CI, const Query &) { + // call undef -> undef + if (isa<UndefValue>(CI->getCalledValue())) + return UndefValue::get(CI->getType()); + + return 0; +} + +/// SimplifyInstruction - See if we can compute a simplified version of this +/// instruction. If not, this returns null. +Value *llvm::SimplifyInstruction(Instruction *I, const TargetData *TD, + const TargetLibraryInfo *TLI, + const DominatorTree *DT) { + Value *Result; + + switch (I->getOpcode()) { + default: + Result = ConstantFoldInstruction(I, TD, TLI); + break; + case Instruction::Add: + Result = SimplifyAddInst(I->getOperand(0), I->getOperand(1), + cast<BinaryOperator>(I)->hasNoSignedWrap(), + cast<BinaryOperator>(I)->hasNoUnsignedWrap(), + TD, TLI, DT); + break; + case Instruction::Sub: + Result = SimplifySubInst(I->getOperand(0), I->getOperand(1), + cast<BinaryOperator>(I)->hasNoSignedWrap(), + cast<BinaryOperator>(I)->hasNoUnsignedWrap(), + TD, TLI, DT); + break; + case Instruction::Mul: + Result = SimplifyMulInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT); + break; + case Instruction::SDiv: + Result = SimplifySDivInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT); + break; + case Instruction::UDiv: + Result = SimplifyUDivInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT); + break; + case Instruction::FDiv: + Result = SimplifyFDivInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT); + break; + case Instruction::SRem: + Result = SimplifySRemInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT); + break; + case Instruction::URem: + Result = SimplifyURemInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT); + break; + case Instruction::FRem: + Result = SimplifyFRemInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT); + break; + case Instruction::Shl: + Result = SimplifyShlInst(I->getOperand(0), I->getOperand(1), + cast<BinaryOperator>(I)->hasNoSignedWrap(), + cast<BinaryOperator>(I)->hasNoUnsignedWrap(), + TD, TLI, DT); + break; + case Instruction::LShr: + Result = SimplifyLShrInst(I->getOperand(0), I->getOperand(1), + cast<BinaryOperator>(I)->isExact(), + TD, TLI, DT); + break; + case Instruction::AShr: + Result = SimplifyAShrInst(I->getOperand(0), I->getOperand(1), + cast<BinaryOperator>(I)->isExact(), + TD, TLI, DT); + break; + case Instruction::And: + Result = SimplifyAndInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT); + break; + case Instruction::Or: + Result = SimplifyOrInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT); + break; + case Instruction::Xor: + Result = SimplifyXorInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT); + break; + case Instruction::ICmp: + Result = SimplifyICmpInst(cast<ICmpInst>(I)->getPredicate(), + I->getOperand(0), I->getOperand(1), TD, TLI, DT); + break; + case Instruction::FCmp: + Result = SimplifyFCmpInst(cast<FCmpInst>(I)->getPredicate(), + I->getOperand(0), I->getOperand(1), TD, TLI, DT); + break; + case Instruction::Select: + Result = SimplifySelectInst(I->getOperand(0), I->getOperand(1), + I->getOperand(2), TD, TLI, DT); + break; + case Instruction::GetElementPtr: { + SmallVector<Value*, 8> Ops(I->op_begin(), I->op_end()); + Result = SimplifyGEPInst(Ops, TD, TLI, DT); + break; + } + case Instruction::InsertValue: { + InsertValueInst *IV = cast<InsertValueInst>(I); + Result = SimplifyInsertValueInst(IV->getAggregateOperand(), + IV->getInsertedValueOperand(), + IV->getIndices(), TD, TLI, DT); + break; + } + case Instruction::PHI: + Result = SimplifyPHINode(cast<PHINode>(I), Query (TD, TLI, DT)); + break; + case Instruction::Call: + Result = SimplifyCallInst(cast<CallInst>(I), Query (TD, TLI, DT)); + break; + case Instruction::Trunc: + Result = SimplifyTruncInst(I->getOperand(0), I->getType(), TD, TLI, DT); + break; + } + + /// If called on unreachable code, the above logic may report that the + /// instruction simplified to itself. Make life easier for users by + /// detecting that case here, returning a safe value instead. + return Result == I ? UndefValue::get(I->getType()) : Result; +} + +/// \brief Implementation of recursive simplification through an instructions +/// uses. +/// +/// This is the common implementation of the recursive simplification routines. +/// If we have a pre-simplified value in 'SimpleV', that is forcibly used to +/// replace the instruction 'I'. Otherwise, we simply add 'I' to the list of +/// instructions to process and attempt to simplify it using +/// InstructionSimplify. +/// +/// This routine returns 'true' only when *it* simplifies something. The passed +/// in simplified value does not count toward this. +static bool replaceAndRecursivelySimplifyImpl(Instruction *I, Value *SimpleV, + const TargetData *TD, + const TargetLibraryInfo *TLI, + const DominatorTree *DT) { + bool Simplified = false; + SmallSetVector<Instruction *, 8> Worklist; + + // If we have an explicit value to collapse to, do that round of the + // simplification loop by hand initially. + if (SimpleV) { + for (Value::use_iterator UI = I->use_begin(), UE = I->use_end(); UI != UE; + ++UI) + if (*UI != I) + Worklist.insert(cast<Instruction>(*UI)); + + // Replace the instruction with its simplified value. + I->replaceAllUsesWith(SimpleV); + + // Gracefully handle edge cases where the instruction is not wired into any + // parent block. + if (I->getParent()) + I->eraseFromParent(); + } else { + Worklist.insert(I); + } + + // Note that we must test the size on each iteration, the worklist can grow. + for (unsigned Idx = 0; Idx != Worklist.size(); ++Idx) { + I = Worklist[Idx]; + + // See if this instruction simplifies. + SimpleV = SimplifyInstruction(I, TD, TLI, DT); + if (!SimpleV) + continue; + + Simplified = true; + + // Stash away all the uses of the old instruction so we can check them for + // recursive simplifications after a RAUW. This is cheaper than checking all + // uses of To on the recursive step in most cases. + for (Value::use_iterator UI = I->use_begin(), UE = I->use_end(); UI != UE; + ++UI) + Worklist.insert(cast<Instruction>(*UI)); + + // Replace the instruction with its simplified value. + I->replaceAllUsesWith(SimpleV); + + // Gracefully handle edge cases where the instruction is not wired into any + // parent block. + if (I->getParent()) + I->eraseFromParent(); + } + return Simplified; +} + +bool llvm::recursivelySimplifyInstruction(Instruction *I, + const TargetData *TD, + const TargetLibraryInfo *TLI, + const DominatorTree *DT) { + return replaceAndRecursivelySimplifyImpl(I, 0, TD, TLI, DT); +} + +bool llvm::replaceAndRecursivelySimplify(Instruction *I, Value *SimpleV, + const TargetData *TD, + const TargetLibraryInfo *TLI, + const DominatorTree *DT) { + assert(I != SimpleV && "replaceAndRecursivelySimplify(X,X) is not valid!"); + assert(SimpleV && "Must provide a simplified value."); + return replaceAndRecursivelySimplifyImpl(I, SimpleV, TD, TLI, DT); +} |
