[InstCombine] Employ AliasAnalysis in FindAvailableLoadedValue

llvm-svn: 241887

lib/Transforms/InstCombine/InstCombineInternal.h

@@ -15,6 +15,7 @@
 #ifndef LLVM_LIB_TRANSFORMS_INSTCOMBINE_INSTCOMBINEINTERNAL_H
 #define LLVM_LIB_TRANSFORMS_INSTCOMBINE_INSTCOMBINEINTERNAL_H
 
+#include "llvm/Analysis/AliasAnalysis.h"
 #include "llvm/Analysis/AssumptionCache.h"
 #include "llvm/Analysis/LoopInfo.h"
 #include "llvm/Analysis/TargetFolder.h"
@@ -177,6 +178,8 @@ private:
   // Mode in which we are running the combiner.
   const bool MinimizeSize;
 
+  AliasAnalysis *AA;
+
   // Required analyses.
   // FIXME: These can never be null and should be references.
   AssumptionCache *AC;
@@ -192,10 +195,11 @@ private:
 
 public:
   InstCombiner(InstCombineWorklist &Worklist, BuilderTy *Builder,
-               bool MinimizeSize, AssumptionCache *AC, TargetLibraryInfo *TLI,
+               bool MinimizeSize, AliasAnalysis *AA,
+               AssumptionCache *AC, TargetLibraryInfo *TLI,
                DominatorTree *DT, const DataLayout &DL, LoopInfo *LI)
       : Worklist(Worklist), Builder(Builder), MinimizeSize(MinimizeSize),
-        AC(AC), TLI(TLI), DT(DT), DL(DL), LI(LI), MadeIRChange(false) {}
+        AA(AA), AC(AC), TLI(TLI), DT(DT), DL(DL), LI(LI), MadeIRChange(false) {}
 
   /// \brief Run the combiner over the entire worklist until it is empty.
   ///

lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp

@@ -751,7 +751,7 @@ Instruction *InstCombiner::visitLoadInst(LoadInst &LI) {
   BasicBlock::iterator BBI = &LI;
   AAMDNodes AATags;
   if (Value *AvailableVal = FindAvailableLoadedValue(Op, LI.getParent(), BBI,
-                                                     6, nullptr, &AATags)) {
+                                                     6, AA, &AATags)) {
     if (LoadInst *NLI = dyn_cast<LoadInst>(AvailableVal)) {
       unsigned KnownIDs[] = {
         LLVMContext::MD_tbaa,

lib/Transforms/InstCombine/InstructionCombining.cpp

@@ -2972,8 +2972,9 @@ static bool prepareICWorklistFromFunction(Function &F, const DataLayout &DL,
 
 static bool
 combineInstructionsOverFunction(Function &F, InstCombineWorklist &Worklist,
-                                AssumptionCache &AC, TargetLibraryInfo &TLI,
+                                AliasAnalysis *AA, AssumptionCache &AC,
-                                DominatorTree &DT, LoopInfo *LI = nullptr) {
+                                TargetLibraryInfo &TLI, DominatorTree &DT,
+                                LoopInfo *LI = nullptr) {
   // Minimizing size?
   bool MinimizeSize = F.hasFnAttribute(Attribute::MinSize);
   auto &DL = F.getParent()->getDataLayout();
@@ -2998,7 +2999,8 @@ combineInstructionsOverFunction(Function &F, InstCombineWorklist &Worklist,
     if (prepareICWorklistFromFunction(F, DL, &TLI, Worklist))
       Changed = true;
 
-    InstCombiner IC(Worklist, &Builder, MinimizeSize, &AC, &TLI, &DT, DL, LI);
+    InstCombiner IC(Worklist, &Builder, MinimizeSize,
+                    AA, &AC, &TLI, &DT, DL, LI);
     if (IC.run())
       Changed = true;
 
@@ -3017,7 +3019,8 @@ PreservedAnalyses InstCombinePass::run(Function &F,
 
   auto *LI = AM->getCachedResult<LoopAnalysis>(F);
 
-  if (!combineInstructionsOverFunction(F, Worklist, AC, TLI, DT, LI))
+  // FIXME: The AliasAnalysis is not yet supported in the new pass manager
+  if (!combineInstructionsOverFunction(F, Worklist, nullptr, AC, TLI, DT, LI))
     // No changes, all analyses are preserved.
     return PreservedAnalyses::all();
 
@@ -3050,6 +3053,7 @@ public:
 
 void InstructionCombiningPass::getAnalysisUsage(AnalysisUsage &AU) const {
   AU.setPreservesCFG();
+  AU.addRequired<AliasAnalysis>();
   AU.addRequired<AssumptionCacheTracker>();
   AU.addRequired<TargetLibraryInfoWrapperPass>();
   AU.addRequired<DominatorTreeWrapperPass>();
@@ -3061,6 +3065,7 @@ bool InstructionCombiningPass::runOnFunction(Function &F) {
     return false;
 
   // Required analyses.
+  auto AA = &getAnalysis<AliasAnalysis>();
   auto &AC = getAnalysis<AssumptionCacheTracker>().getAssumptionCache(F);
   auto &TLI = getAnalysis<TargetLibraryInfoWrapperPass>().getTLI();
   auto &DT = getAnalysis<DominatorTreeWrapperPass>().getDomTree();
@@ -3069,7 +3074,7 @@ bool InstructionCombiningPass::runOnFunction(Function &F) {
   auto *LIWP = getAnalysisIfAvailable<LoopInfoWrapperPass>();
   auto *LI = LIWP ? &LIWP->getLoopInfo() : nullptr;
 
-  return combineInstructionsOverFunction(F, Worklist, AC, TLI, DT, LI);
+  return combineInstructionsOverFunction(F, Worklist, AA, AC, TLI, DT, LI);
 }
 
 char InstructionCombiningPass::ID = 0;
@@ -3078,6 +3083,7 @@ INITIALIZE_PASS_BEGIN(InstructionCombiningPass, "instcombine",
 INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker)
 INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)
 INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
+INITIALIZE_AG_DEPENDENCY(AliasAnalysis)
 INITIALIZE_PASS_END(InstructionCombiningPass, "instcombine",
                     "Combine redundant instructions", false, false)
 

test/Transforms/InstCombine/load_combine_aa.ll

@@ -0,0 +1,15 @@
+; RUN: opt -basicaa -instcombine -S < %s | FileCheck %s
+
+; CHECK-LABEL: @test_load_combine_aa(
+; CHECK: %[[V:.*]] = load i32, i32* %0
+; CHECK: store i32 0, i32* %3
+; CHECK: store i32 %[[V]], i32* %1
+; CHECK: store i32 %[[V]], i32* %2
+define void @test_load_combine_aa(i32*, i32*, i32*, i32* noalias) {
+  %a = load i32, i32* %0
+  store i32 0, i32* %3
+  %b = load i32, i32* %0
+  store i32 %a, i32* %1
+  store i32 %b, i32* %2
+  ret void
+}