diff --git a/include/llvm/Transforms/Scalar.h b/include/llvm/Transforms/Scalar.h index ae4f32e0b0e..7832c93be99 100644 --- a/include/llvm/Transforms/Scalar.h +++ b/include/llvm/Transforms/Scalar.h @@ -129,9 +129,12 @@ FunctionPass *createLICMPass(); //===----------------------------------------------------------------------===// // // LoopStrengthReduce - This pass is strength reduces GEP instructions that use -// a loop's canonical induction variable as one of their indices. +// a loop's canonical induction variable as one of their indices. The +// MaxTargetAMSize is the largest element size that the target architecture +// can handle in its addressing modes. Power of two multipliers less than or +// equal to this value are not reduced. // -FunctionPass *createLoopStrengthReducePass(); +FunctionPass *createLoopStrengthReducePass(unsigned MaxTargetAMSize = 1); //===----------------------------------------------------------------------===// // diff --git a/lib/Transforms/Scalar/LoopStrengthReduce.cpp b/lib/Transforms/Scalar/LoopStrengthReduce.cpp index 56bc43e62f3..52b6b9887a7 100644 --- a/lib/Transforms/Scalar/LoopStrengthReduce.cpp +++ b/lib/Transforms/Scalar/LoopStrengthReduce.cpp @@ -22,10 +22,12 @@ #include "llvm/Constants.h" #include "llvm/Instructions.h" #include "llvm/Type.h" +#include "llvm/DerivedTypes.h" #include "llvm/Analysis/Dominators.h" #include "llvm/Analysis/LoopInfo.h" #include "llvm/Support/CFG.h" #include "llvm/Transforms/Utils/Local.h" +#include "llvm/Target/TargetData.h" #include "llvm/ADT/Statistic.h" #include using namespace llvm; @@ -37,7 +39,12 @@ namespace { LoopInfo *LI; DominatorSet *DS; bool Changed; + unsigned MaxTargetAMSize; public: + LoopStrengthReduce(unsigned MTAMS = 1) + : MaxTargetAMSize(MTAMS) { + } + virtual bool runOnFunction(Function &) { LI = &getAnalysis(); DS = &getAnalysis(); @@ -53,6 +60,7 @@ namespace { AU.addRequiredID(LoopSimplifyID); AU.addRequired(); AU.addRequired(); + AU.addRequired(); } private: void runOnLoop(Loop *L); @@ -65,8 +73,8 @@ namespace { "Strength Reduce GEP Uses of Ind. Vars"); } -FunctionPass *llvm::createLoopStrengthReducePass() { - return new LoopStrengthReduce(); +FunctionPass *llvm::createLoopStrengthReducePass(unsigned MaxTargetAMSize) { + return new LoopStrengthReduce(MaxTargetAMSize); } /// DeleteTriviallyDeadInstructions - If any of the instructions is the @@ -104,6 +112,7 @@ void LoopStrengthReduce::strengthReduceGEP(GetElementPtrInst *GEPI, Loop *L, unsigned indvar = 0; std::vector pre_op_vector; std::vector inc_op_vector; + const Type *ty = GEPI->getOperand(0)->getType(); Value *CanonicalIndVar = L->getCanonicalInductionVariable(); BasicBlock *Header = L->getHeader(); BasicBlock *Preheader = L->getLoopPreheader(); @@ -111,6 +120,14 @@ void LoopStrengthReduce::strengthReduceGEP(GetElementPtrInst *GEPI, Loop *L, for (unsigned op = 1, e = GEPI->getNumOperands(); op != e; ++op) { Value *operand = GEPI->getOperand(op); + if (ty->getTypeID() == Type::StructTyID) { + assert(isa(operand)); + ConstantUInt *c = dyn_cast(operand); + ty = ty->getContainedType(unsigned(c->getValue())); + } else { + ty = ty->getContainedType(0); + } + if (operand == CanonicalIndVar) { // FIXME: use getCanonicalInductionVariableIncrement to choose between // one and neg one maybe? We need to support int *foo = GEP base, -1 @@ -139,6 +156,12 @@ void LoopStrengthReduce::strengthReduceGEP(GetElementPtrInst *GEPI, Loop *L, if (Instruction *GepPtrOp = dyn_cast(GEPI->getOperand(0))) if (!DS->dominates(GepPtrOp, Preheader->getTerminator())) return; + + // Don't reduced multiplies that the target can handle via addressing modes. + uint64_t sz = getAnalysis().getTypeSize(ty); + for (unsigned i = 1; i <= MaxTargetAMSize; i *= 2) + if (i == sz) + return; // If all operands of the GEP we are going to insert into the preheader // are constants, generate a GEP ConstantExpr instead.