From feafcd96881581f9d41d4fb98cfd214fedd356c4 Mon Sep 17 00:00:00 2001 From: Adam Nemet Date: Thu, 1 Dec 2016 03:56:43 +0000 Subject: [PATCH] [GVN] When merging blocks update LoopInfo if it's available If LoopInfo is available during GVN, BasicAA will use it. However MergeBlockIntoPredecessor does not update LI as it merges blocks. This didn't use to cause problems because LI was freed before GVN/BasicAA. Now with OptimizationRemarkEmitter, the lifetime of LI is extended so LI needs to be kept up-to-date during GVN. Differential Revision: https://reviews.llvm.org/D27288 llvm-svn: 288307 --- llvm/include/llvm/Transforms/Scalar/GVN.h | 3 +- llvm/lib/Transforms/Scalar/GVN.cpp | 16 ++++--- llvm/test/Transforms/GVN/stale-loop-info.ll | 50 +++++++++++++++++++++ 3 files changed, 62 insertions(+), 7 deletions(-) create mode 100644 llvm/test/Transforms/GVN/stale-loop-info.ll diff --git a/llvm/include/llvm/Transforms/Scalar/GVN.h b/llvm/include/llvm/Transforms/Scalar/GVN.h index a86a9a8c448a5..5492ba2c1d4b1 100644 --- a/llvm/include/llvm/Transforms/Scalar/GVN.h +++ b/llvm/include/llvm/Transforms/Scalar/GVN.h @@ -22,6 +22,7 @@ #include "llvm/ADT/SmallPtrSet.h" #include "llvm/Analysis/AliasAnalysis.h" #include "llvm/Analysis/AssumptionCache.h" +#include "llvm/Analysis/LoopInfo.h" #include "llvm/Analysis/MemoryDependenceAnalysis.h" #include "llvm/IR/Dominators.h" #include "llvm/IR/IntrinsicInst.h" @@ -134,7 +135,7 @@ class GVN : public PassInfoMixin { bool runImpl(Function &F, AssumptionCache &RunAC, DominatorTree &RunDT, const TargetLibraryInfo &RunTLI, AAResults &RunAA, - MemoryDependenceResults *RunMD); + MemoryDependenceResults *RunMD, LoopInfo *LI); /// Push a new Value to the LeaderTable onto the list for its value number. void addToLeaderTable(uint32_t N, Value *V, const BasicBlock *BB) { diff --git a/llvm/lib/Transforms/Scalar/GVN.cpp b/llvm/lib/Transforms/Scalar/GVN.cpp index d5234c0f7e327..79afff2fe3b91 100644 --- a/llvm/lib/Transforms/Scalar/GVN.cpp +++ b/llvm/lib/Transforms/Scalar/GVN.cpp @@ -586,7 +586,8 @@ PreservedAnalyses GVN::run(Function &F, FunctionAnalysisManager &AM) { auto &TLI = AM.getResult(F); auto &AA = AM.getResult(F); auto &MemDep = AM.getResult(F); - bool Changed = runImpl(F, AC, DT, TLI, AA, &MemDep); + auto *LI = AM.getCachedResult(F); + bool Changed = runImpl(F, AC, DT, TLI, AA, &MemDep, LI); if (!Changed) return PreservedAnalyses::all(); PreservedAnalyses PA; @@ -2179,7 +2180,7 @@ bool GVN::processInstruction(Instruction *I) { /// runOnFunction - This is the main transformation entry point for a function. bool GVN::runImpl(Function &F, AssumptionCache &RunAC, DominatorTree &RunDT, const TargetLibraryInfo &RunTLI, AAResults &RunAA, - MemoryDependenceResults *RunMD) { + MemoryDependenceResults *RunMD, LoopInfo *LI) { AC = &RunAC; DT = &RunDT; VN.setDomTree(DT); @@ -2196,9 +2197,9 @@ bool GVN::runImpl(Function &F, AssumptionCache &RunAC, DominatorTree &RunDT, for (Function::iterator FI = F.begin(), FE = F.end(); FI != FE; ) { BasicBlock *BB = &*FI++; - bool removedBlock = - MergeBlockIntoPredecessor(BB, DT, /* LoopInfo */ nullptr, MD); - if (removedBlock) ++NumGVNBlocks; + bool removedBlock = MergeBlockIntoPredecessor(BB, DT, LI, MD); + if (removedBlock) + ++NumGVNBlocks; Changed |= removedBlock; } @@ -2693,13 +2694,16 @@ class llvm::gvn::GVNLegacyPass : public FunctionPass { if (skipFunction(F)) return false; + auto *LIWP = getAnalysisIfAvailable(); + return Impl.runImpl( F, getAnalysis().getAssumptionCache(F), getAnalysis().getDomTree(), getAnalysis().getTLI(), getAnalysis().getAAResults(), NoLoads ? nullptr - : &getAnalysis().getMemDep()); + : &getAnalysis().getMemDep(), + LIWP ? &LIWP->getLoopInfo() : nullptr); } void getAnalysisUsage(AnalysisUsage &AU) const override { diff --git a/llvm/test/Transforms/GVN/stale-loop-info.ll b/llvm/test/Transforms/GVN/stale-loop-info.ll new file mode 100644 index 0000000000000..dd082c74cf894 --- /dev/null +++ b/llvm/test/Transforms/GVN/stale-loop-info.ll @@ -0,0 +1,50 @@ +; RUN: opt -loops -gvn -S < %s | FileCheck %s + +; This used to fail with ASAN enabled and if for some reason LoopInfo remained +; available during GVN. In this case BasicAA will use LI but +; MergeBlockIntoPredecessor in GVN failed to update LI. + +target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128" + +%struct.wibble.1028 = type { i32, i32, %struct.barney.881 } +%struct.barney.881 = type { %struct.zot.882 } +%struct.zot.882 = type { [64 x i8] } + +; Function Attrs: argmemonly +declare void @snork.1(i8*) local_unnamed_addr #0 + +define hidden zeroext i1 @eggs(%struct.wibble.1028* %arg, i1 %arg2) unnamed_addr align 2 { +bb: + br i1 %arg2, label %bb14, label %bb3 + +bb3: ; preds = %bb + %tmp = getelementptr inbounds %struct.wibble.1028, %struct.wibble.1028* %arg, i64 0, i32 2, i32 0, i32 0, i64 0 + %tmp5 = bitcast i8* %tmp to %struct.wibble.1028** + br label %bb6 + +bb6: ; preds = %bb12, %bb3 + br label %bb7 + +bb7: ; preds = %bb6 + br i1 undef, label %bb11, label %bb8 + +bb8: ; preds = %bb7 + %tmp9 = load %struct.wibble.1028*, %struct.wibble.1028** %tmp5, align 8 +; CHECK: %tmp9 = load %struct.wibble.1028*, %struct.wibble.1028** %tmp5, align 8 + %tmp10 = bitcast %struct.wibble.1028* %tmp9 to i8* + br label %bb12 + +bb11: ; preds = %bb7 + br label %bb12 + +bb12: ; preds = %bb11, %bb8 + %tmp13 = phi i8* [ %tmp, %bb11 ], [ %tmp10, %bb8 ] + call void @snork.1(i8* %tmp13) #1 + br label %bb6 + +bb14: ; preds = %bb + ret i1 false +} + +attributes #0 = { argmemonly } +attributes #1 = { nounwind }