From: Owen Anderson Date: Wed, 2 Dec 2009 07:35:19 +0000 (+0000) Subject: Cleanup/remove some parts of the lifetime region handling code in memdep and GVN, X-Git-Url: http://plrg.eecs.uci.edu/git/?p=oota-llvm.git;a=commitdiff_plain;h=9ff5a23186f8761d9e5b4b5adf6fae9ce7d63860 Cleanup/remove some parts of the lifetime region handling code in memdep and GVN, per Chris' comments. Adjust testcases to match. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@90304 91177308-0d34-0410-b5e6-96231b3b80d8 --- diff --git a/lib/Analysis/MemoryDependenceAnalysis.cpp b/lib/Analysis/MemoryDependenceAnalysis.cpp index f4531e09579..60fe15fe52e 100644 --- a/lib/Analysis/MemoryDependenceAnalysis.cpp +++ b/lib/Analysis/MemoryDependenceAnalysis.cpp @@ -186,15 +186,17 @@ getPointerDependencyFrom(Value *MemPtr, uint64_t MemSize, bool isLoad, } if (IntrinsicInst *II = dyn_cast(Inst)) { + // Debug intrinsics don't cause dependences. + if (isa(Inst)) continue; + // If we pass an invariant-end marker, then we've just entered an // invariant region and can start ignoring dependencies. if (II->getIntrinsicID() == Intrinsic::invariant_end) { - uint64_t InvariantSize = ~0ULL; - if (ConstantInt *CI = dyn_cast(II->getOperand(2))) - InvariantSize = CI->getZExtValue(); - - AliasAnalysis::AliasResult R = - AA->alias(II->getOperand(3), InvariantSize, MemPtr, MemSize); + // FIXME: This only considers queries directly on the invariant-tagged + // pointer, not on query pointers that are indexed off of them. It'd + // be nice to handle that at some point. + AliasAnalysis::AliasResult R = + AA->alias(II->getOperand(3), ~0ULL, MemPtr, ~0ULL); if (R == AliasAnalysis::MustAlias) { InvariantTag = II->getOperand(1); continue; @@ -202,14 +204,12 @@ getPointerDependencyFrom(Value *MemPtr, uint64_t MemSize, bool isLoad, // If we reach a lifetime begin or end marker, then the query ends here // because the value is undefined. - } else if (II->getIntrinsicID() == Intrinsic::lifetime_start || - II->getIntrinsicID() == Intrinsic::lifetime_end) { - uint64_t InvariantSize = ~0ULL; - if (ConstantInt *CI = dyn_cast(II->getOperand(1))) - InvariantSize = CI->getZExtValue(); - + } else if (II->getIntrinsicID() == Intrinsic::lifetime_start) { + // FIXME: This only considers queries directly on the invariant-tagged + // pointer, not on query pointers that are indexed off of them. It'd + // be nice to handle that at some point. AliasAnalysis::AliasResult R = - AA->alias(II->getOperand(2), InvariantSize, MemPtr, MemSize); + AA->alias(II->getOperand(2), ~0ULL, MemPtr, ~0ULL); if (R == AliasAnalysis::MustAlias) return MemDepResult::getDef(II); } @@ -219,9 +219,6 @@ getPointerDependencyFrom(Value *MemPtr, uint64_t MemSize, bool isLoad, // at this point. Nothing a load depends on can live in an invariant region. if (isLoad && InvariantTag) continue; - // Debug intrinsics don't cause dependences. - if (isa(Inst)) continue; - // Values depend on loads if the pointers are must aliased. This means that // a load depends on another must aliased load from the same value. if (LoadInst *LI = dyn_cast(Inst)) { diff --git a/lib/Transforms/Scalar/GVN.cpp b/lib/Transforms/Scalar/GVN.cpp index 1b42c6b9592..ceb57f85a5f 100644 --- a/lib/Transforms/Scalar/GVN.cpp +++ b/lib/Transforms/Scalar/GVN.cpp @@ -1187,10 +1187,9 @@ static Value *ConstructSSAForLoadSet(LoadInst *LI, return V; } -static bool isLifetimeStartOrEnd(Instruction *Inst) { +static bool isLifetimeStart(Instruction *Inst) { if (IntrinsicInst* II = dyn_cast(Inst)) - return II->getIntrinsicID() == Intrinsic::lifetime_start || - II->getIntrinsicID() == Intrinsic::lifetime_end; + return II->getIntrinsicID() == Intrinsic::lifetime_start; return false; } @@ -1262,8 +1261,8 @@ bool GVN::processNonLocalLoad(LoadInst *LI, // Loading the allocation -> undef. if (isa(DepInst) || isMalloc(DepInst) || - // Loading immediately after lifetime begin or end -> undef. - isLifetimeStartOrEnd(DepInst)) { + // Loading immediately after lifetime begin -> undef. + isLifetimeStart(DepInst)) { ValuesPerBlock.push_back(AvailableValueInBlock::get(DepBB, UndefValue::get(LI->getType()))); continue; @@ -1635,11 +1634,10 @@ bool GVN::processLoad(LoadInst *L, SmallVectorImpl &toErase) { return true; } - // If this load occurs either right after a lifetime begin or a lifetime end, + // If this load occurs either right after a lifetime begin, // then the loaded value is undefined. if (IntrinsicInst* II = dyn_cast(DepInst)) { - if (II->getIntrinsicID() == Intrinsic::lifetime_start || - II->getIntrinsicID() == Intrinsic::lifetime_end) { + if (II->getIntrinsicID() == Intrinsic::lifetime_start) { L->replaceAllUsesWith(UndefValue::get(L->getType())); toErase.push_back(L); NumGVNLoad++; diff --git a/test/Transforms/DeadStoreElimination/lifetime-simple.ll b/test/Transforms/DeadStoreElimination/lifetime-simple.ll deleted file mode 100644 index 430e7006351..00000000000 --- a/test/Transforms/DeadStoreElimination/lifetime-simple.ll +++ /dev/null @@ -1,18 +0,0 @@ -; RUN: opt < %s -dse -S | FileCheck %s - -target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128" -target triple = "i386-apple-darwin7" - -define i8 @test2(i8* %P) nounwind { -; CHECK: @test2 -; CHECK-NOT: store i8 1 -; CHECK: ret i8 0 -entry: - call void @llvm.lifetime.start(i64 32, i8* %P) - call void @llvm.lifetime.end(i64 32, i8* %P) - store i8 1, i8* %P - ret i8 0 -} - -declare {}* @llvm.lifetime.start(i64 %S, i8* nocapture %P) readonly -declare void @llvm.lifetime.end(i64 %S, i8* nocapture %P) \ No newline at end of file diff --git a/test/Transforms/GVN/lifetime-simple.ll b/test/Transforms/GVN/lifetime-simple.ll index 00a0c2907c1..8139246dcf3 100644 --- a/test/Transforms/GVN/lifetime-simple.ll +++ b/test/Transforms/GVN/lifetime-simple.ll @@ -4,9 +4,9 @@ target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f3 target triple = "i386-apple-darwin7" define i8 @test(i8* %P) nounwind { -; CHECK: @test +; CHECK: lifetime.start ; CHECK-NOT: load -; CHECK: ret i8 undef +; CHECK: lifetime.end entry: call void @llvm.lifetime.start(i64 32, i8* %P) %0 = load i8* %P