From e19e4baf3b4f145fad122de7e6a02ed3a68bc082 Mon Sep 17 00:00:00 2001 From: Chris Lattner Date: Fri, 27 Nov 2009 00:34:38 +0000 Subject: teach phi translation of GEPs to simplify geps like 'gep x, 0'. This allows us to compile the example from PR5313 into: LBB1_2: ## %bb incl %ecx movb %al, (%rsi) movslq %ecx, %rax movb (%rdi,%rax), %al testb %al, %al jne LBB1_2 instead of: LBB1_2: ## %bb movslq %eax, %rcx incl %eax movb (%rdi,%rcx), %cl movb %cl, (%rsi) movslq %eax, %rcx cmpb $0, (%rdi,%rcx) jne LBB1_2 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89981 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Analysis/MemoryDependenceAnalysis.cpp | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) (limited to 'lib') diff --git a/lib/Analysis/MemoryDependenceAnalysis.cpp b/lib/Analysis/MemoryDependenceAnalysis.cpp index 6bffca61e0..d7497514f5 100644 --- a/lib/Analysis/MemoryDependenceAnalysis.cpp +++ b/lib/Analysis/MemoryDependenceAnalysis.cpp @@ -20,6 +20,7 @@ #include "llvm/IntrinsicInst.h" #include "llvm/Function.h" #include "llvm/Analysis/AliasAnalysis.h" +#include "llvm/Analysis/InstructionSimplify.h" #include "llvm/Analysis/MemoryBuiltins.h" #include "llvm/ADT/Statistic.h" #include "llvm/ADT/STLExtras.h" @@ -716,7 +717,8 @@ static bool isPHITranslatable(Instruction *Inst) { /// PHITranslateForPred - Given a computation that satisfied the /// isPHITranslatable predicate, see if we can translate the computation into /// the specified predecessor block. If so, return that value. -static Value *PHITranslateForPred(Instruction *Inst, BasicBlock *Pred) { +static Value *PHITranslateForPred(Instruction *Inst, BasicBlock *Pred, + const TargetData *TD) { if (PHINode *PN = dyn_cast(Inst)) return PN->getIncomingValueForBlock(Pred); @@ -751,7 +753,9 @@ static Value *PHITranslateForPred(Instruction *Inst, BasicBlock *Pred) { GEPOps.back() = APHIOp = PN->getIncomingValueForBlock(Pred); } - // TODO: Simplify the GEP to handle 'gep x, 0' -> x etc. + // Simplify the GEP to handle 'gep x, 0' -> x etc. + if (Value *V = SimplifyGEPInst(&GEPOps[0], GEPOps.size(), TD)) + return V; // Scan to see if we have this GEP available. for (Value::use_iterator UI = APHIOp->use_begin(), E = APHIOp->use_end(); @@ -926,7 +930,7 @@ getNonLocalPointerDepFromBB(Value *Pointer, uint64_t PointeeSize, for (BasicBlock **PI = PredCache->GetPreds(BB); *PI; ++PI) { BasicBlock *Pred = *PI; - Value *PredPtr = PHITranslateForPred(PtrInst, Pred); + Value *PredPtr = PHITranslateForPred(PtrInst, Pred, TD); // If PHI translation fails, bail out. if (PredPtr == 0) -- cgit v1.2.3