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-rw-r--r--contrib/llvm/lib/Analysis/ValueTracking.cpp238
1 files changed, 29 insertions, 209 deletions
diff --git a/contrib/llvm/lib/Analysis/ValueTracking.cpp b/contrib/llvm/lib/Analysis/ValueTracking.cpp
index b4c9884..181c9b0 100644
--- a/contrib/llvm/lib/Analysis/ValueTracking.cpp
+++ b/contrib/llvm/lib/Analysis/ValueTracking.cpp
@@ -880,19 +880,20 @@ bool llvm::ComputeMultiple(Value *V, unsigned Base, Value *&Multiple,
}
Value *Mul0 = NULL;
- Value *Mul1 = NULL;
- bool M0 = ComputeMultiple(Op0, Base, Mul0,
- LookThroughSExt, Depth+1);
- bool M1 = ComputeMultiple(Op1, Base, Mul1,
- LookThroughSExt, Depth+1);
-
- if (M0) {
- if (isa<Constant>(Op1) && isa<Constant>(Mul0)) {
- // V == Base * (Mul0 * Op1), so return (Mul0 * Op1)
- Multiple = ConstantExpr::getMul(cast<Constant>(Mul0),
- cast<Constant>(Op1));
- return true;
- }
+ if (ComputeMultiple(Op0, Base, Mul0, LookThroughSExt, Depth+1)) {
+ if (Constant *Op1C = dyn_cast<Constant>(Op1))
+ if (Constant *MulC = dyn_cast<Constant>(Mul0)) {
+ if (Op1C->getType()->getPrimitiveSizeInBits() <
+ MulC->getType()->getPrimitiveSizeInBits())
+ Op1C = ConstantExpr::getZExt(Op1C, MulC->getType());
+ if (Op1C->getType()->getPrimitiveSizeInBits() >
+ MulC->getType()->getPrimitiveSizeInBits())
+ MulC = ConstantExpr::getZExt(MulC, Op1C->getType());
+
+ // V == Base * (Mul0 * Op1), so return (Mul0 * Op1)
+ Multiple = ConstantExpr::getMul(MulC, Op1C);
+ return true;
+ }
if (ConstantInt *Mul0CI = dyn_cast<ConstantInt>(Mul0))
if (Mul0CI->getValue() == 1) {
@@ -902,13 +903,21 @@ bool llvm::ComputeMultiple(Value *V, unsigned Base, Value *&Multiple,
}
}
- if (M1) {
- if (isa<Constant>(Op0) && isa<Constant>(Mul1)) {
- // V == Base * (Mul1 * Op0), so return (Mul1 * Op0)
- Multiple = ConstantExpr::getMul(cast<Constant>(Mul1),
- cast<Constant>(Op0));
- return true;
- }
+ Value *Mul1 = NULL;
+ if (ComputeMultiple(Op1, Base, Mul1, LookThroughSExt, Depth+1)) {
+ if (Constant *Op0C = dyn_cast<Constant>(Op0))
+ if (Constant *MulC = dyn_cast<Constant>(Mul1)) {
+ if (Op0C->getType()->getPrimitiveSizeInBits() <
+ MulC->getType()->getPrimitiveSizeInBits())
+ Op0C = ConstantExpr::getZExt(Op0C, MulC->getType());
+ if (Op0C->getType()->getPrimitiveSizeInBits() >
+ MulC->getType()->getPrimitiveSizeInBits())
+ MulC = ConstantExpr::getZExt(MulC, Op0C->getType());
+
+ // V == Base * (Mul1 * Op0), so return (Mul1 * Op0)
+ Multiple = ConstantExpr::getMul(MulC, Op0C);
+ return true;
+ }
if (ConstantInt *Mul1CI = dyn_cast<ConstantInt>(Mul1))
if (Mul1CI->getValue() == 1) {
@@ -973,195 +982,6 @@ bool llvm::CannotBeNegativeZero(const Value *V, unsigned Depth) {
return false;
}
-
-/// GetLinearExpression - Analyze the specified value as a linear expression:
-/// "A*V + B", where A and B are constant integers. Return the scale and offset
-/// values as APInts and return V as a Value*. The incoming Value is known to
-/// have IntegerType. Note that this looks through extends, so the high bits
-/// may not be represented in the result.
-static Value *GetLinearExpression(Value *V, APInt &Scale, APInt &Offset,
- const TargetData *TD, unsigned Depth) {
- assert(V->getType()->isIntegerTy() && "Not an integer value");
-
- // Limit our recursion depth.
- if (Depth == 6) {
- Scale = 1;
- Offset = 0;
- return V;
- }
-
- if (BinaryOperator *BOp = dyn_cast<BinaryOperator>(V)) {
- if (ConstantInt *RHSC = dyn_cast<ConstantInt>(BOp->getOperand(1))) {
- switch (BOp->getOpcode()) {
- default: break;
- case Instruction::Or:
- // X|C == X+C if all the bits in C are unset in X. Otherwise we can't
- // analyze it.
- if (!MaskedValueIsZero(BOp->getOperand(0), RHSC->getValue(), TD))
- break;
- // FALL THROUGH.
- case Instruction::Add:
- V = GetLinearExpression(BOp->getOperand(0), Scale, Offset, TD, Depth+1);
- Offset += RHSC->getValue();
- return V;
- case Instruction::Mul:
- V = GetLinearExpression(BOp->getOperand(0), Scale, Offset, TD, Depth+1);
- Offset *= RHSC->getValue();
- Scale *= RHSC->getValue();
- return V;
- case Instruction::Shl:
- V = GetLinearExpression(BOp->getOperand(0), Scale, Offset, TD, Depth+1);
- Offset <<= RHSC->getValue().getLimitedValue();
- Scale <<= RHSC->getValue().getLimitedValue();
- return V;
- }
- }
- }
-
- // Since clients don't care about the high bits of the value, just scales and
- // offsets, we can look through extensions.
- if (isa<SExtInst>(V) || isa<ZExtInst>(V)) {
- Value *CastOp = cast<CastInst>(V)->getOperand(0);
- unsigned OldWidth = Scale.getBitWidth();
- unsigned SmallWidth = CastOp->getType()->getPrimitiveSizeInBits();
- Scale.trunc(SmallWidth);
- Offset.trunc(SmallWidth);
- Value *Result = GetLinearExpression(CastOp, Scale, Offset, TD, Depth+1);
- Scale.zext(OldWidth);
- Offset.zext(OldWidth);
- return Result;
- }
-
- Scale = 1;
- Offset = 0;
- return V;
-}
-
-/// DecomposeGEPExpression - If V is a symbolic pointer expression, decompose it
-/// into a base pointer with a constant offset and a number of scaled symbolic
-/// offsets.
-///
-/// The scaled symbolic offsets (represented by pairs of a Value* and a scale in
-/// the VarIndices vector) are Value*'s that are known to be scaled by the
-/// specified amount, but which may have other unrepresented high bits. As such,
-/// the gep cannot necessarily be reconstructed from its decomposed form.
-///
-/// When TargetData is around, this function is capable of analyzing everything
-/// that Value::getUnderlyingObject() can look through. When not, it just looks
-/// through pointer casts.
-///
-const Value *llvm::DecomposeGEPExpression(const Value *V, int64_t &BaseOffs,
- SmallVectorImpl<std::pair<const Value*, int64_t> > &VarIndices,
- const TargetData *TD) {
- // Limit recursion depth to limit compile time in crazy cases.
- unsigned MaxLookup = 6;
-
- BaseOffs = 0;
- do {
- // See if this is a bitcast or GEP.
- const Operator *Op = dyn_cast<Operator>(V);
- if (Op == 0) {
- // The only non-operator case we can handle are GlobalAliases.
- if (const GlobalAlias *GA = dyn_cast<GlobalAlias>(V)) {
- if (!GA->mayBeOverridden()) {
- V = GA->getAliasee();
- continue;
- }
- }
- return V;
- }
-
- if (Op->getOpcode() == Instruction::BitCast) {
- V = Op->getOperand(0);
- continue;
- }
-
- const GEPOperator *GEPOp = dyn_cast<GEPOperator>(Op);
- if (GEPOp == 0)
- return V;
-
- // Don't attempt to analyze GEPs over unsized objects.
- if (!cast<PointerType>(GEPOp->getOperand(0)->getType())
- ->getElementType()->isSized())
- return V;
-
- // If we are lacking TargetData information, we can't compute the offets of
- // elements computed by GEPs. However, we can handle bitcast equivalent
- // GEPs.
- if (!TD) {
- if (!GEPOp->hasAllZeroIndices())
- return V;
- V = GEPOp->getOperand(0);
- continue;
- }
-
- // Walk the indices of the GEP, accumulating them into BaseOff/VarIndices.
- gep_type_iterator GTI = gep_type_begin(GEPOp);
- for (User::const_op_iterator I = GEPOp->op_begin()+1,
- E = GEPOp->op_end(); I != E; ++I) {
- Value *Index = *I;
- // Compute the (potentially symbolic) offset in bytes for this index.
- if (const StructType *STy = dyn_cast<StructType>(*GTI++)) {
- // For a struct, add the member offset.
- unsigned FieldNo = cast<ConstantInt>(Index)->getZExtValue();
- if (FieldNo == 0) continue;
-
- BaseOffs += TD->getStructLayout(STy)->getElementOffset(FieldNo);
- continue;
- }
-
- // For an array/pointer, add the element offset, explicitly scaled.
- if (ConstantInt *CIdx = dyn_cast<ConstantInt>(Index)) {
- if (CIdx->isZero()) continue;
- BaseOffs += TD->getTypeAllocSize(*GTI)*CIdx->getSExtValue();
- continue;
- }
-
- uint64_t Scale = TD->getTypeAllocSize(*GTI);
-
- // Use GetLinearExpression to decompose the index into a C1*V+C2 form.
- unsigned Width = cast<IntegerType>(Index->getType())->getBitWidth();
- APInt IndexScale(Width, 0), IndexOffset(Width, 0);
- Index = GetLinearExpression(Index, IndexScale, IndexOffset, TD, 0);
-
- // The GEP index scale ("Scale") scales C1*V+C2, yielding (C1*V+C2)*Scale.
- // This gives us an aggregate computation of (C1*Scale)*V + C2*Scale.
- BaseOffs += IndexOffset.getZExtValue()*Scale;
- Scale *= IndexScale.getZExtValue();
-
-
- // If we already had an occurrance of this index variable, merge this
- // scale into it. For example, we want to handle:
- // A[x][x] -> x*16 + x*4 -> x*20
- // This also ensures that 'x' only appears in the index list once.
- for (unsigned i = 0, e = VarIndices.size(); i != e; ++i) {
- if (VarIndices[i].first == Index) {
- Scale += VarIndices[i].second;
- VarIndices.erase(VarIndices.begin()+i);
- break;
- }
- }
-
- // Make sure that we have a scale that makes sense for this target's
- // pointer size.
- if (unsigned ShiftBits = 64-TD->getPointerSizeInBits()) {
- Scale <<= ShiftBits;
- Scale >>= ShiftBits;
- }
-
- if (Scale)
- VarIndices.push_back(std::make_pair(Index, Scale));
- }
-
- // Analyze the base pointer next.
- V = GEPOp->getOperand(0);
- } while (--MaxLookup);
-
- // If the chain of expressions is too deep, just return early.
- return V;
-}
-
-
// This is the recursive version of BuildSubAggregate. It takes a few different
// arguments. Idxs is the index within the nested struct From that we are
// looking at now (which is of type IndexedType). IdxSkip is the number of
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