diff options
Diffstat (limited to 'llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp')
| -rw-r--r-- | llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp | 38 |
1 files changed, 21 insertions, 17 deletions
diff --git a/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp b/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp index fbe3171f81f..d81ea2b7994 100644 --- a/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp +++ b/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp @@ -178,7 +178,7 @@ private: bool FindIVForUser(ICmpInst *Cond, IVStrideUse *&CondUse, const SCEVHandle *&CondStride); bool RequiresTypeConversion(const Type *Ty, const Type *NewTy); - unsigned CheckForIVReuse(bool, const SCEVHandle&, + unsigned CheckForIVReuse(bool, bool, const SCEVHandle&, IVExpr&, const Type*, const std::vector<BasedUser>& UsersToProcess); bool ValidStride(bool, int64_t, @@ -980,15 +980,17 @@ bool LoopStrengthReduce::ValidStride(bool HasBaseReg, /// RequiresTypeConversion - Returns true if converting Ty to NewTy is not /// a nop. -bool LoopStrengthReduce::RequiresTypeConversion(const Type *Ty, - const Type *NewTy) { - if (Ty == NewTy) +bool LoopStrengthReduce::RequiresTypeConversion(const Type *Ty1, + const Type *Ty2) { + if (Ty1 == Ty2) return false; - return (!Ty->canLosslesslyBitCastTo(NewTy) && - !(isa<PointerType>(NewTy) && - Ty->canLosslesslyBitCastTo(UIntPtrTy)) && - !(isa<PointerType>(Ty) && - NewTy->canLosslesslyBitCastTo(UIntPtrTy))); + if (TLI && TLI->isTruncateFree(Ty1, Ty2)) + return false; + return (!Ty1->canLosslesslyBitCastTo(Ty2) && + !(isa<PointerType>(Ty2) && + Ty1->canLosslesslyBitCastTo(UIntPtrTy)) && + !(isa<PointerType>(Ty1) && + Ty2->canLosslesslyBitCastTo(UIntPtrTy))); } /// CheckForIVReuse - Returns the multiple if the stride is the multiple @@ -997,20 +999,23 @@ bool LoopStrengthReduce::RequiresTypeConversion(const Type *Ty, /// this stride to be rewritten as prev iv * factor. It returns 0 if no /// reuse is possible. unsigned LoopStrengthReduce::CheckForIVReuse(bool HasBaseReg, + bool AllUsesAreAddresses, const SCEVHandle &Stride, IVExpr &IV, const Type *Ty, const std::vector<BasedUser>& UsersToProcess) { if (SCEVConstant *SC = dyn_cast<SCEVConstant>(Stride)) { int64_t SInt = SC->getValue()->getSExtValue(); - if (SInt == 1) return 0; - for (std::map<SCEVHandle, IVsOfOneStride>::iterator SI= IVsByStride.begin(), SE = IVsByStride.end(); SI != SE; ++SI) { int64_t SSInt = cast<SCEVConstant>(SI->first)->getValue()->getSExtValue(); - if (SInt != -SSInt && + if (SI->first != Stride && (unsigned(abs(SInt)) < SSInt || (SInt % SSInt) != 0)) continue; int64_t Scale = SInt / SSInt; + // When scale is 1, we don't need to worry about whether the + // multiplication can be folded into the addressing mode. + if (!AllUsesAreAddresses && Scale != 1) + continue; // Check that this stride is valid for all the types used for loads and // stores; if it can be used for some and not others, we might as well use // the original stride everywhere, since we have to create the IV for it @@ -1021,7 +1026,7 @@ unsigned LoopStrengthReduce::CheckForIVReuse(bool HasBaseReg, // FIXME: Only handle base == 0 for now. // Only reuse previous IV if it would not require a type conversion. if (isZero(II->Base) && - !RequiresTypeConversion(II->Base->getType(),Ty)) { + !RequiresTypeConversion(II->Base->getType(), Ty)) { IV = *II; return Scale; } @@ -1183,10 +1188,9 @@ void LoopStrengthReduce::StrengthReduceStridedIVUsers(const SCEVHandle &Stride, SE->getIntegerSCEV(0, Type::Int32Ty), 0, 0); unsigned RewriteFactor = 0; - if (AllUsesAreAddresses) - RewriteFactor = CheckForIVReuse(HaveCommonExprs, Stride, ReuseIV, - CommonExprs->getType(), - UsersToProcess); + RewriteFactor = CheckForIVReuse(HaveCommonExprs, AllUsesAreAddresses, + Stride, ReuseIV, CommonExprs->getType(), + UsersToProcess); if (RewriteFactor != 0) { DOUT << "BASED ON IV of STRIDE " << *ReuseIV.Stride << " and BASE " << *ReuseIV.Base << " :\n"; |
