[llvm] r325880 - Mark MergedLoadStoreMotion as not preserving MemDep results
Bjorn Steinbrink via llvm-commits
llvm-commits at lists.llvm.org
Fri Feb 23 02:41:57 PST 2018
Author: bsteinbr
Date: Fri Feb 23 02:41:57 2018
New Revision: 325880
URL: http://llvm.org/viewvc/llvm-project?rev=325880&view=rev
Log:
Mark MergedLoadStoreMotion as not preserving MemDep results
Summary:
MemDep caches results that signify that a dependence is non-local, and
there is currently no way to invalidate such cache entries.
Unfortunately, when MLSM sinks a store that can result in a non-local
dependence becoming a local one, and then MemDep gives wrong answers.
The easiest way out here is to just say that MLSM does indeed not
preserve MemDep results.
Reviewers: davide, Gerolf
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D43177
Added:
llvm/trunk/test/Transforms/GVN/pr36063.ll
Modified:
llvm/trunk/lib/Transforms/Scalar/MergedLoadStoreMotion.cpp
Modified: llvm/trunk/lib/Transforms/Scalar/MergedLoadStoreMotion.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/MergedLoadStoreMotion.cpp?rev=325880&r1=325879&r2=325880&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/MergedLoadStoreMotion.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/MergedLoadStoreMotion.cpp Fri Feb 23 02:41:57 2018
@@ -80,7 +80,6 @@
#include "llvm/Analysis/CFG.h"
#include "llvm/Analysis/GlobalsModRef.h"
#include "llvm/Analysis/Loads.h"
-#include "llvm/Analysis/MemoryDependenceAnalysis.h"
#include "llvm/Analysis/ValueTracking.h"
#include "llvm/IR/Metadata.h"
#include "llvm/Support/Debug.h"
@@ -97,7 +96,6 @@ namespace {
// MergedLoadStoreMotion Pass
//===----------------------------------------------------------------------===//
class MergedLoadStoreMotion {
- MemoryDependenceResults *MD = nullptr;
AliasAnalysis *AA = nullptr;
// The mergeLoad/Store algorithms could have Size0 * Size1 complexity,
@@ -107,14 +105,9 @@ class MergedLoadStoreMotion {
const int MagicCompileTimeControl = 250;
public:
- bool run(Function &F, MemoryDependenceResults *MD, AliasAnalysis &AA);
+ bool run(Function &F, AliasAnalysis &AA);
private:
- ///
- /// \brief Remove instruction from parent and update memory dependence
- /// analysis.
- ///
- void removeInstruction(Instruction *Inst);
BasicBlock *getDiamondTail(BasicBlock *BB);
bool isDiamondHead(BasicBlock *BB);
// Routines for sinking stores
@@ -128,22 +121,6 @@ private:
} // end anonymous namespace
///
-/// \brief Remove instruction from parent and update memory dependence analysis.
-///
-void MergedLoadStoreMotion::removeInstruction(Instruction *Inst) {
- // Notify the memory dependence analysis.
- if (MD) {
- MD->removeInstruction(Inst);
- if (auto *LI = dyn_cast<LoadInst>(Inst))
- MD->invalidateCachedPointerInfo(LI->getPointerOperand());
- if (Inst->getType()->isPtrOrPtrVectorTy()) {
- MD->invalidateCachedPointerInfo(Inst);
- }
- }
- Inst->eraseFromParent();
-}
-
-///
/// \brief Return tail block of a diamond.
///
BasicBlock *MergedLoadStoreMotion::getDiamondTail(BasicBlock *BB) {
@@ -236,8 +213,6 @@ PHINode *MergedLoadStoreMotion::getPHIOp
&BB->front());
NewPN->addIncoming(Opd1, S0->getParent());
NewPN->addIncoming(Opd2, S1->getParent());
- if (MD && NewPN->getType()->isPtrOrPtrVectorTy())
- MD->invalidateCachedPointerInfo(NewPN);
return NewPN;
}
@@ -275,12 +250,12 @@ bool MergedLoadStoreMotion::sinkStore(Ba
// New PHI operand? Use it.
if (PHINode *NewPN = getPHIOperand(BB, S0, S1))
SNew->setOperand(0, NewPN);
- removeInstruction(S0);
- removeInstruction(S1);
+ S0->eraseFromParent();
+ S1->eraseFromParent();
A0->replaceAllUsesWith(ANew);
- removeInstruction(A0);
+ A0->eraseFromParent();
A1->replaceAllUsesWith(ANew);
- removeInstruction(A1);
+ A1->eraseFromParent();
return true;
}
return false;
@@ -344,9 +319,7 @@ bool MergedLoadStoreMotion::mergeStores(
return MergedStores;
}
-bool MergedLoadStoreMotion::run(Function &F, MemoryDependenceResults *MD,
- AliasAnalysis &AA) {
- this->MD = MD;
+bool MergedLoadStoreMotion::run(Function &F, AliasAnalysis &AA) {
this->AA = &AA;
bool Changed = false;
@@ -382,9 +355,7 @@ public:
if (skipFunction(F))
return false;
MergedLoadStoreMotion Impl;
- auto *MDWP = getAnalysisIfAvailable<MemoryDependenceWrapperPass>();
- return Impl.run(F, MDWP ? &MDWP->getMemDep() : nullptr,
- getAnalysis<AAResultsWrapperPass>().getAAResults());
+ return Impl.run(F, getAnalysis<AAResultsWrapperPass>().getAAResults());
}
private:
@@ -392,7 +363,6 @@ private:
AU.setPreservesCFG();
AU.addRequired<AAResultsWrapperPass>();
AU.addPreserved<GlobalsAAWrapperPass>();
- AU.addPreserved<MemoryDependenceWrapperPass>();
}
};
@@ -408,7 +378,6 @@ FunctionPass *llvm::createMergedLoadStor
INITIALIZE_PASS_BEGIN(MergedLoadStoreMotionLegacyPass, "mldst-motion",
"MergedLoadStoreMotion", false, false)
-INITIALIZE_PASS_DEPENDENCY(MemoryDependenceWrapperPass)
INITIALIZE_PASS_DEPENDENCY(AAResultsWrapperPass)
INITIALIZE_PASS_END(MergedLoadStoreMotionLegacyPass, "mldst-motion",
"MergedLoadStoreMotion", false, false)
@@ -416,14 +385,12 @@ INITIALIZE_PASS_END(MergedLoadStoreMotio
PreservedAnalyses
MergedLoadStoreMotionPass::run(Function &F, FunctionAnalysisManager &AM) {
MergedLoadStoreMotion Impl;
- auto *MD = AM.getCachedResult<MemoryDependenceAnalysis>(F);
auto &AA = AM.getResult<AAManager>(F);
- if (!Impl.run(F, MD, AA))
+ if (!Impl.run(F, AA))
return PreservedAnalyses::all();
PreservedAnalyses PA;
PA.preserveSet<CFGAnalyses>();
PA.preserve<GlobalsAA>();
- PA.preserve<MemoryDependenceAnalysis>();
return PA;
}
Added: llvm/trunk/test/Transforms/GVN/pr36063.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/GVN/pr36063.ll?rev=325880&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/GVN/pr36063.ll (added)
+++ llvm/trunk/test/Transforms/GVN/pr36063.ll Fri Feb 23 02:41:57 2018
@@ -0,0 +1,22 @@
+; RUN: opt < %s -memcpyopt -mldst-motion -gvn -S | FileCheck %s
+
+define void @foo(i8* %ret, i1 %x) {
+ %a = alloca i8
+ br i1 %x, label %yes, label %no
+
+yes: ; preds = %0
+ %gepa = getelementptr i8, i8* %a, i64 0
+ store i8 5, i8* %gepa
+ br label %out
+
+no: ; preds = %0
+ %gepb = getelementptr i8, i8* %a, i64 0
+ store i8 5, i8* %gepb
+ br label %out
+
+out: ; preds = %no, %yes
+ %tmp = load i8, i8* %a
+; CHECK-NOT: undef
+ store i8 %tmp, i8* %ret
+ ret void
+}
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