diff options
| author | Chris Lattner <sabre@nondot.org> | 2011-05-22 07:03:34 +0000 |
|---|---|---|
| committer | Chris Lattner <sabre@nondot.org> | 2011-05-22 07:03:34 +0000 |
| commit | 9e7bc05ad7fb69a25aff37e348942b07eed9cd73 (patch) | |
| tree | 7c0dc3ada0e8f21d05cf8d95991ffd787b9fc96c | |
| parent | 0e959394ad5b74970253d21069ae11f25290e1fc (diff) | |
fix PR9841 by having GVN not process dead loads. This was
causing it to get into infinite loops when it would widen a
load (which can necessarily leave around dead loads).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131847 91177308-0d34-0410-b5e6-96231b3b80d8
| -rw-r--r-- | lib/Transforms/Scalar/GVN.cpp | 5 | ||||
| -rw-r--r-- | test/Transforms/GVN/crash.ll | 12 |
2 files changed, 17 insertions, 0 deletions
diff --git a/lib/Transforms/Scalar/GVN.cpp b/lib/Transforms/Scalar/GVN.cpp index 1da5238bbb..2515fd112c 100644 --- a/lib/Transforms/Scalar/GVN.cpp +++ b/lib/Transforms/Scalar/GVN.cpp @@ -1607,6 +1607,11 @@ bool GVN::processLoad(LoadInst *L) { if (L->isVolatile()) return false; + if (L->use_empty()) { + markInstructionForDeletion(L); + return true; + } + // ... to a pointer that has been loaded from before... MemDepResult Dep = MD->getDependency(L); diff --git a/test/Transforms/GVN/crash.ll b/test/Transforms/GVN/crash.ll index 4a3aa1c55a..31eae256c6 100644 --- a/test/Transforms/GVN/crash.ll +++ b/test/Transforms/GVN/crash.ll @@ -151,3 +151,15 @@ dead: dead2: ret i32 %A } + + +; PR9841 +define fastcc i8 @test5(i8* %P) nounwind { +entry: + %0 = load i8* %P, align 2 + + %Q = getelementptr i8* %P, i32 1 + %1 = load i8* %Q, align 1 + ret i8 %1 +} + |