commit e62fc3d0b6ce923dcbc29eeb6ebc5808e6724f90
author Matt Morehouse <mascasa@google.com> Wed Sep 19 19:37:24 2018 +0000
committer Matt Morehouse <mascasa@google.com> Wed Sep 19 19:37:24 2018 +0000
tree e5fadc259b3b063b9ddb6a12d82ce1c5b67a9c81
parent a4526d77c9921c86a29889fc09de17f7d5ccb210

[InstCombine] Disable strcmp->memcmp transform for MSan.

Summary:
The strcmp->memcmp transform can make the resulting memcmp read
uninitialized data, which MSan doesn't like.

Resolves https://github.com/google/sanitizers/issues/993.

Reviewers: eugenis, xbolva00

Reviewed By: eugenis

Subscribers: hiraditya, llvm-commits

Differential Revision: https://reviews.llvm.org/D52272

llvm-svn: 342582

llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp

diff --git a/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp b/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
index 8fa2279..3789181 100644
--- a/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
@@ -171,7 +171,10 @@
 
   if (!isDereferenceableAndAlignedPointer(Str, 1, APInt(64, Len), DL))
     return false;
-    
+
+  if (CI->getFunction()->hasFnAttribute(Attribute::SanitizeMemory))
+    return false;
+
   return true;
 }