1 files changed, 393 insertions, 28 deletions

diff --git a/contrib/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp b/contrib/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
index cefe45e..173f2bf 100644
--- a/contrib/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
+++ b/contrib/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
@@ -13,8 +13,8 @@
 //===----------------------------------------------------------------------===//
 
 #include "InstCombine.h"
-#include "llvm/IntrinsicInst.h"
 #include "llvm/Analysis/InstructionSimplify.h"
+#include "llvm/IR/IntrinsicInst.h"
 #include "llvm/Support/PatternMatch.h"
 using namespace llvm;
 using namespace PatternMatch;
@@ -37,7 +37,7 @@ static Value *simplifyValueKnownNonZero(Value *V, InstCombiner &IC) {
   if (match(V, m_LShr(m_OneUse(m_Shl(m_Value(PowerOf2), m_Value(A))),
                       m_Value(B))) &&
       // The "1" can be any value known to be a power of 2.
-      isPowerOfTwo(PowerOf2, IC.getDataLayout())) {
+      isKnownToBeAPowerOfTwo(PowerOf2)) {
     A = IC.Builder->CreateSub(A, B);
     return IC.Builder->CreateShl(PowerOf2, A);
   }
@@ -45,8 +45,7 @@ static Value *simplifyValueKnownNonZero(Value *V, InstCombiner &IC) {
   // (PowerOfTwo >>u B) --> isExact since shifting out the result would make it
   // inexact.  Similarly for <<.
   if (BinaryOperator *I = dyn_cast<BinaryOperator>(V))
-    if (I->isLogicalShift() &&
-        isPowerOfTwo(I->getOperand(0), IC.getDataLayout())) {
+    if (I->isLogicalShift() && isKnownToBeAPowerOfTwo(I->getOperand(0))) {
       // We know that this is an exact/nuw shift and that the input is a
       // non-zero context as well.
       if (Value *V2 = simplifyValueKnownNonZero(I->getOperand(0), IC)) {
@@ -252,24 +251,136 @@ Instruction *InstCombiner::visitMul(BinaryOperator &I) {
   return Changed ? &I : 0;
 }
 
+//
+// Detect pattern:
+//
+// log2(Y*0.5)
+//
+// And check for corresponding fast math flags
+//
+
+static void detectLog2OfHalf(Value *&Op, Value *&Y, IntrinsicInst *&Log2) {
+
+   if (!Op->hasOneUse())
+     return;
+
+   IntrinsicInst *II = dyn_cast<IntrinsicInst>(Op);
+   if (!II)
+     return;
+   if (II->getIntrinsicID() != Intrinsic::log2 || !II->hasUnsafeAlgebra())
+     return;
+   Log2 = II;
+
+   Value *OpLog2Of = II->getArgOperand(0);
+   if (!OpLog2Of->hasOneUse())
+     return;
+
+   Instruction *I = dyn_cast<Instruction>(OpLog2Of);
+   if (!I)
+     return;
+   if (I->getOpcode() != Instruction::FMul || !I->hasUnsafeAlgebra())
+     return;
+              
+   ConstantFP *CFP = dyn_cast<ConstantFP>(I->getOperand(0));
+   if (CFP && CFP->isExactlyValue(0.5)) {
+     Y = I->getOperand(1);
+     return;
+   }
+   CFP = dyn_cast<ConstantFP>(I->getOperand(1));
+   if (CFP && CFP->isExactlyValue(0.5))
+     Y = I->getOperand(0);
+} 
+
+/// Helper function of InstCombiner::visitFMul(BinaryOperator(). It returns
+/// true iff the given value is FMul or FDiv with one and only one operand
+/// being a normal constant (i.e. not Zero/NaN/Infinity).
+static bool isFMulOrFDivWithConstant(Value *V) {
+  Instruction *I = dyn_cast<Instruction>(V);
+  if (!I || (I->getOpcode() != Instruction::FMul && 
+             I->getOpcode() != Instruction::FDiv))
+    return false;
+
+  ConstantFP *C0 = dyn_cast<ConstantFP>(I->getOperand(0));
+  ConstantFP *C1 = dyn_cast<ConstantFP>(I->getOperand(1));
+
+  if (C0 && C1)
+    return false;
+
+  return (C0 && C0->getValueAPF().isNormal()) ||
+         (C1 && C1->getValueAPF().isNormal());
+}
+
+static bool isNormalFp(const ConstantFP *C) {
+  const APFloat &Flt = C->getValueAPF();
+  return Flt.isNormal() && !Flt.isDenormal();
+}
+
+/// foldFMulConst() is a helper routine of InstCombiner::visitFMul().
+/// The input \p FMulOrDiv is a FMul/FDiv with one and only one operand
+/// being a constant (i.e. isFMulOrFDivWithConstant(FMulOrDiv) == true).
+/// This function is to simplify "FMulOrDiv * C" and returns the 
+/// resulting expression. Note that this function could return NULL in
+/// case the constants cannot be folded into a normal floating-point.
+/// 
+Value *InstCombiner::foldFMulConst(Instruction *FMulOrDiv, ConstantFP *C,
+                                   Instruction *InsertBefore) {
+  assert(isFMulOrFDivWithConstant(FMulOrDiv) && "V is invalid");
+
+  Value *Opnd0 = FMulOrDiv->getOperand(0);
+  Value *Opnd1 = FMulOrDiv->getOperand(1);
+
+  ConstantFP *C0 = dyn_cast<ConstantFP>(Opnd0);
+  ConstantFP *C1 = dyn_cast<ConstantFP>(Opnd1);
+
+  BinaryOperator *R = 0;
+
+  // (X * C0) * C => X * (C0*C)
+  if (FMulOrDiv->getOpcode() == Instruction::FMul) {
+    Constant *F = ConstantExpr::getFMul(C1 ? C1 : C0, C);
+    if (isNormalFp(cast<ConstantFP>(F)))
+      R = BinaryOperator::CreateFMul(C1 ? Opnd0 : Opnd1, F);
+  } else {
+    if (C0) {
+      // (C0 / X) * C => (C0 * C) / X
+      ConstantFP *F = cast<ConstantFP>(ConstantExpr::getFMul(C0, C));
+      if (isNormalFp(F))
+        R = BinaryOperator::CreateFDiv(F, Opnd1);
+    } else {
+      // (X / C1) * C => X * (C/C1) if C/C1 is not a denormal
+      ConstantFP *F = cast<ConstantFP>(ConstantExpr::getFDiv(C, C1));
+      if (isNormalFp(F)) {
+        R = BinaryOperator::CreateFMul(Opnd0, F);
+      } else {
+        // (X / C1) * C => X / (C1/C) 
+        Constant *F = ConstantExpr::getFDiv(C1, C);
+        if (isNormalFp(cast<ConstantFP>(F)))
+          R = BinaryOperator::CreateFDiv(Opnd0, F);
+      }
+    }
+  }
+
+  if (R) {
+    R->setHasUnsafeAlgebra(true);
+    InsertNewInstWith(R, *InsertBefore);
+  }
+
+  return R;
+}
+
 Instruction *InstCombiner::visitFMul(BinaryOperator &I) {
   bool Changed = SimplifyAssociativeOrCommutative(I);
   Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
 
-  // Simplify mul instructions with a constant RHS.
-  if (Constant *Op1C = dyn_cast<Constant>(Op1)) {
-    if (ConstantFP *Op1F = dyn_cast<ConstantFP>(Op1C)) {
-      // "In IEEE floating point, x*1 is not equivalent to x for nans.  However,
-      // ANSI says we can drop signals, so we can do this anyway." (from GCC)
-      if (Op1F->isExactlyValue(1.0))
-        return ReplaceInstUsesWith(I, Op0);  // Eliminate 'fmul double %X, 1.0'
-    } else if (ConstantDataVector *Op1V = dyn_cast<ConstantDataVector>(Op1C)) {
-      // As above, vector X*splat(1.0) -> X in all defined cases.
-      if (ConstantFP *F = dyn_cast_or_null<ConstantFP>(Op1V->getSplatValue()))
-        if (F->isExactlyValue(1.0))
-          return ReplaceInstUsesWith(I, Op0);
-    }
+  if (isa<Constant>(Op0))
+    std::swap(Op0, Op1);
+
+  if (Value *V = SimplifyFMulInst(Op0, Op1, I.getFastMathFlags(), TD))
+    return ReplaceInstUsesWith(I, V);
+
+  bool AllowReassociate = I.hasUnsafeAlgebra();
 
+  // Simplify mul instructions with a constant RHS.
+  if (isa<Constant>(Op1)) {
     // Try to fold constant mul into select arguments.
     if (SelectInst *SI = dyn_cast<SelectInst>(Op0))
       if (Instruction *R = FoldOpIntoSelect(I, SI))
@@ -278,11 +389,146 @@ Instruction *InstCombiner::visitFMul(BinaryOperator &I) {
     if (isa<PHINode>(Op0))
       if (Instruction *NV = FoldOpIntoPhi(I))
         return NV;
+
+    ConstantFP *C = dyn_cast<ConstantFP>(Op1);
+    if (C && AllowReassociate && C->getValueAPF().isNormal()) {
+      // Let MDC denote an expression in one of these forms:
+      // X * C, C/X, X/C, where C is a constant.
+      //
+      // Try to simplify "MDC * Constant"
+      if (isFMulOrFDivWithConstant(Op0)) {
+        Value *V = foldFMulConst(cast<Instruction>(Op0), C, &I);
+        if (V)
+          return ReplaceInstUsesWith(I, V);
+      }
+
+      // (MDC +/- C1) * C => (MDC * C) +/- (C1 * C)
+      Instruction *FAddSub = dyn_cast<Instruction>(Op0);
+      if (FAddSub &&
+          (FAddSub->getOpcode() == Instruction::FAdd ||
+           FAddSub->getOpcode() == Instruction::FSub)) {
+        Value *Opnd0 = FAddSub->getOperand(0);
+        Value *Opnd1 = FAddSub->getOperand(1);
+        ConstantFP *C0 = dyn_cast<ConstantFP>(Opnd0);
+        ConstantFP *C1 = dyn_cast<ConstantFP>(Opnd1);
+        bool Swap = false;
+        if (C0) {
+          std::swap(C0, C1);
+          std::swap(Opnd0, Opnd1);
+          Swap = true; 
+        }
+
+        if (C1 && C1->getValueAPF().isNormal() &&
+            isFMulOrFDivWithConstant(Opnd0)) {
+          Value *M1 = ConstantExpr::getFMul(C1, C);
+          Value *M0 = isNormalFp(cast<ConstantFP>(M1)) ? 
+                      foldFMulConst(cast<Instruction>(Opnd0), C, &I) :
+                      0;
+          if (M0 && M1) {
+            if (Swap && FAddSub->getOpcode() == Instruction::FSub)
+              std::swap(M0, M1);
+
+            Value *R = (FAddSub->getOpcode() == Instruction::FAdd) ?
+                        BinaryOperator::CreateFAdd(M0, M1) :
+                        BinaryOperator::CreateFSub(M0, M1);
+            Instruction *RI = cast<Instruction>(R);
+            RI->copyFastMathFlags(&I);
+            return RI;
+          }
+        }
+      }
+    }
+  }
+
+
+  // Under unsafe algebra do:
+  // X * log2(0.5*Y) = X*log2(Y) - X
+  if (I.hasUnsafeAlgebra()) {
+    Value *OpX = NULL;
+    Value *OpY = NULL;
+    IntrinsicInst *Log2;
+    detectLog2OfHalf(Op0, OpY, Log2);
+    if (OpY) {
+      OpX = Op1;
+    } else {
+      detectLog2OfHalf(Op1, OpY, Log2);
+      if (OpY) {
+        OpX = Op0;
+      }
+    }
+    // if pattern detected emit alternate sequence
+    if (OpX && OpY) {
+      Log2->setArgOperand(0, OpY);
+      Value *FMulVal = Builder->CreateFMul(OpX, Log2);
+      Instruction *FMul = cast<Instruction>(FMulVal);
+      FMul->copyFastMathFlags(Log2);
+      Instruction *FSub = BinaryOperator::CreateFSub(FMulVal, OpX);
+      FSub->copyFastMathFlags(Log2);
+      return FSub;
+    }
   }
 
-  if (Value *Op0v = dyn_castFNegVal(Op0))     // -X * -Y = X*Y
-    if (Value *Op1v = dyn_castFNegVal(Op1))
-      return BinaryOperator::CreateFMul(Op0v, Op1v);
+  // Handle symmetric situation in a 2-iteration loop
+  Value *Opnd0 = Op0;
+  Value *Opnd1 = Op1;
+  for (int i = 0; i < 2; i++) {
+    bool IgnoreZeroSign = I.hasNoSignedZeros();
+    if (BinaryOperator::isFNeg(Opnd0, IgnoreZeroSign)) {
+      Value *N0 = dyn_castFNegVal(Opnd0, IgnoreZeroSign);
+      Value *N1 = dyn_castFNegVal(Opnd1, IgnoreZeroSign);
+
+      // -X * -Y => X*Y
+      if (N1)
+        return BinaryOperator::CreateFMul(N0, N1);
+
+      if (Opnd0->hasOneUse()) {
+        // -X * Y => -(X*Y) (Promote negation as high as possible)
+        Value *T = Builder->CreateFMul(N0, Opnd1);
+        cast<Instruction>(T)->setDebugLoc(I.getDebugLoc());
+        Instruction *Neg = BinaryOperator::CreateFNeg(T);
+        if (I.getFastMathFlags().any()) {
+          cast<Instruction>(T)->copyFastMathFlags(&I);
+          Neg->copyFastMathFlags(&I);
+        }
+        return Neg;
+      }
+    }
+
+    // (X*Y) * X => (X*X) * Y where Y != X
+    //  The purpose is two-fold: 
+    //   1) to form a power expression (of X).
+    //   2) potentially shorten the critical path: After transformation, the
+    //  latency of the instruction Y is amortized by the expression of X*X,
+    //  and therefore Y is in a "less critical" position compared to what it
+    //  was before the transformation.
+    //
+    if (AllowReassociate) {
+      Value *Opnd0_0, *Opnd0_1;
+      if (Opnd0->hasOneUse() &&
+          match(Opnd0, m_FMul(m_Value(Opnd0_0), m_Value(Opnd0_1)))) {
+        Value *Y = 0;
+        if (Opnd0_0 == Opnd1 && Opnd0_1 != Opnd1)
+          Y = Opnd0_1;
+        else if (Opnd0_1 == Opnd1 && Opnd0_0 != Opnd1)
+          Y = Opnd0_0;
+
+        if (Y) {
+          Instruction *T = cast<Instruction>(Builder->CreateFMul(Opnd1, Opnd1));
+          T->copyFastMathFlags(&I);
+          T->setDebugLoc(I.getDebugLoc());
+
+          Instruction *R = BinaryOperator::CreateFMul(T, Y);
+          R->copyFastMathFlags(&I);
+          return R;
+        }
+      }
+    }
+
+    if (!isa<Constant>(Op1))
+      std::swap(Opnd0, Opnd1);
+    else
+      break;
+  }
 
   return Changed ? &I : 0;
 }
@@ -567,21 +813,140 @@ Instruction *InstCombiner::visitSDiv(BinaryOperator &I) {
   return 0;
 }
 
+/// CvtFDivConstToReciprocal tries to convert X/C into X*1/C if C not a special
+/// FP value and:
+///    1) 1/C is exact, or 
+///    2) reciprocal is allowed.
+/// If the convertion was successful, the simplified expression "X * 1/C" is
+/// returned; otherwise, NULL is returned.
+///
+static Instruction *CvtFDivConstToReciprocal(Value *Dividend,
+                                             ConstantFP *Divisor,
+                                             bool AllowReciprocal) {
+  const APFloat &FpVal = Divisor->getValueAPF();
+  APFloat Reciprocal(FpVal.getSemantics());
+  bool Cvt = FpVal.getExactInverse(&Reciprocal);
+    
+  if (!Cvt && AllowReciprocal && FpVal.isNormal()) {
+    Reciprocal = APFloat(FpVal.getSemantics(), 1.0f);
+    (void)Reciprocal.divide(FpVal, APFloat::rmNearestTiesToEven);
+    Cvt = !Reciprocal.isDenormal();
+  }
+
+  if (!Cvt)
+    return 0;
+
+  ConstantFP *R;
+  R = ConstantFP::get(Dividend->getType()->getContext(), Reciprocal);
+  return BinaryOperator::CreateFMul(Dividend, R);
+}
+
 Instruction *InstCombiner::visitFDiv(BinaryOperator &I) {
   Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
 
   if (Value *V = SimplifyFDivInst(Op0, Op1, TD))
     return ReplaceInstUsesWith(I, V);
 
+  bool AllowReassociate = I.hasUnsafeAlgebra();
+  bool AllowReciprocal = I.hasAllowReciprocal();
+
   if (ConstantFP *Op1C = dyn_cast<ConstantFP>(Op1)) {
-    const APFloat &Op1F = Op1C->getValueAPF();
-
-    // If the divisor has an exact multiplicative inverse we can turn the fdiv
-    // into a cheaper fmul.
-    APFloat Reciprocal(Op1F.getSemantics());
-    if (Op1F.getExactInverse(&Reciprocal)) {
-      ConstantFP *RFP = ConstantFP::get(Builder->getContext(), Reciprocal);
-      return BinaryOperator::CreateFMul(Op0, RFP);
+    if (AllowReassociate) {
+      ConstantFP *C1 = 0;
+      ConstantFP *C2 = Op1C;
+      Value *X;
+      Instruction *Res = 0;
+
+      if (match(Op0, m_FMul(m_Value(X), m_ConstantFP(C1)))) {
+        // (X*C1)/C2 => X * (C1/C2)
+        //
+        Constant *C = ConstantExpr::getFDiv(C1, C2);
+        const APFloat &F = cast<ConstantFP>(C)->getValueAPF();
+        if (F.isNormal() && !F.isDenormal())
+          Res = BinaryOperator::CreateFMul(X, C);
+      } else if (match(Op0, m_FDiv(m_Value(X), m_ConstantFP(C1)))) {
+        // (X/C1)/C2 => X /(C2*C1) [=> X * 1/(C2*C1) if reciprocal is allowed]
+        //
+        Constant *C = ConstantExpr::getFMul(C1, C2);
+        const APFloat &F = cast<ConstantFP>(C)->getValueAPF();
+        if (F.isNormal() && !F.isDenormal()) {
+          Res = CvtFDivConstToReciprocal(X, cast<ConstantFP>(C), 
+                                         AllowReciprocal);
+          if (!Res)
+            Res = BinaryOperator::CreateFDiv(X, C); 
+        }
+      }
+
+      if (Res) {
+        Res->setFastMathFlags(I.getFastMathFlags());
+        return Res;
+      }
+    }
+
+    // X / C => X * 1/C
+    if (Instruction *T = CvtFDivConstToReciprocal(Op0, Op1C, AllowReciprocal))
+      return T;
+
+    return 0;
+  }
+
+  if (AllowReassociate && isa<ConstantFP>(Op0)) {
+    ConstantFP *C1 = cast<ConstantFP>(Op0), *C2;
+    Constant *Fold = 0;
+    Value *X;
+    bool CreateDiv = true;
+
+    // C1 / (X*C2) => (C1/C2) / X
+    if (match(Op1, m_FMul(m_Value(X), m_ConstantFP(C2))))
+      Fold = ConstantExpr::getFDiv(C1, C2);
+    else if (match(Op1, m_FDiv(m_Value(X), m_ConstantFP(C2)))) {
+      // C1 / (X/C2) => (C1*C2) / X
+      Fold = ConstantExpr::getFMul(C1, C2);
+    } else if (match(Op1, m_FDiv(m_ConstantFP(C2), m_Value(X)))) {
+      // C1 / (C2/X) => (C1/C2) * X
+      Fold = ConstantExpr::getFDiv(C1, C2);
+      CreateDiv = false;
+    }
+
+    if (Fold) {
+      const APFloat &FoldC = cast<ConstantFP>(Fold)->getValueAPF();
+      if (FoldC.isNormal() && !FoldC.isDenormal()) {
+        Instruction *R = CreateDiv ? 
+                         BinaryOperator::CreateFDiv(Fold, X) :
+                         BinaryOperator::CreateFMul(X, Fold);
+        R->setFastMathFlags(I.getFastMathFlags());
+        return R;
+      }
+    }
+    return 0;
+  }
+
+  if (AllowReassociate) {
+    Value *X, *Y;
+    Value *NewInst = 0;
+    Instruction *SimpR = 0;
+
+    if (Op0->hasOneUse() && match(Op0, m_FDiv(m_Value(X), m_Value(Y)))) {
+      // (X/Y) / Z => X / (Y*Z)
+      //
+      if (!isa<ConstantFP>(Y) || !isa<ConstantFP>(Op1)) {
+        NewInst = Builder->CreateFMul(Y, Op1);
+        SimpR = BinaryOperator::CreateFDiv(X, NewInst);
+      }
+    } else if (Op1->hasOneUse() && match(Op1, m_FDiv(m_Value(X), m_Value(Y)))) {
+      // Z / (X/Y) => Z*Y / X
+      //
+      if (!isa<ConstantFP>(Y) || !isa<ConstantFP>(Op0)) {
+        NewInst = Builder->CreateFMul(Op0, Y);
+        SimpR = BinaryOperator::CreateFDiv(NewInst, X);
+      }
+    }
+
+    if (NewInst) {
+      if (Instruction *T = dyn_cast<Instruction>(NewInst))
+        T->setDebugLoc(I.getDebugLoc());
+      SimpR->setFastMathFlags(I.getFastMathFlags());
+      return SimpR;
     }
   }