diff options
| -rw-r--r-- | lib/Analysis/BasicAliasAnalysis.cpp | 5 | ||||
| -rw-r--r-- | test/Transforms/DeadStoreElimination/simple.ll | 15 |
2 files changed, 18 insertions, 2 deletions
diff --git a/lib/Analysis/BasicAliasAnalysis.cpp b/lib/Analysis/BasicAliasAnalysis.cpp index 3e63424090..74bee947a3 100644 --- a/lib/Analysis/BasicAliasAnalysis.cpp +++ b/lib/Analysis/BasicAliasAnalysis.cpp @@ -687,10 +687,15 @@ BasicAliasAnalysis::getModRefInfo(ImmutableCallSite CS, Len = LenCI->getZExtValue(); Value *Dest = II->getArgOperand(0); Value *Src = II->getArgOperand(1); + // If it can't overlap the source dest, then it doesn't modref the loc. if (isNoAlias(Location(Dest, Len), Loc)) { if (isNoAlias(Location(Src, Len), Loc)) return NoModRef; + // If it can't overlap the dest, then worst case it reads the loc. Min = Ref; + } else if (isNoAlias(Location(Src, Len), Loc)) { + // If it can't overlap the source, then worst case it mutates the loc. + Min = Mod; } break; } diff --git a/test/Transforms/DeadStoreElimination/simple.ll b/test/Transforms/DeadStoreElimination/simple.ll index c426c0a08b..3237ae2d4f 100644 --- a/test/Transforms/DeadStoreElimination/simple.ll +++ b/test/Transforms/DeadStoreElimination/simple.ll @@ -55,16 +55,27 @@ define void @test5(i32* %Q) { ; CHECK-NEXT: ret void } -declare void @llvm.memset.i32(i8*, i8, i32, i32) +declare void @llvm.memset.i64(i8*, i8, i64, i32) +declare void @llvm.memcpy.i64(i8*, i8*, i64, i32) ; Should delete store of 10 even though memset is a may-store to P (P and Q may ; alias). define void @test6(i32 *%p, i8 *%q) { store i32 10, i32* %p, align 4 ;; dead. - call void @llvm.memset.i32(i8* %q, i8 42, i32 900, i32 1) + call void @llvm.memset.i64(i8* %q, i8 42, i64 900, i32 1) store i32 30, i32* %p, align 4 ret void ; CHECK: @test6 ; CHECK-NEXT: call void @llvm.memset } +; Should delete store of 10 even though memcpy is a may-store to P (P and Q may +; alias). +define void @test7(i32 *%p, i8 *%q, i8* noalias %r) { + store i32 10, i32* %p, align 4 ;; dead. + call void @llvm.memcpy.i64(i8* %q, i8* %r, i64 900, i32 1) + store i32 30, i32* %p, align 4 + ret void +; CHECK: @test7 +; CHECK-NEXT: call void @llvm.memcpy +} |