The patch resolves the conflict between AddressSanitizer and load widening (GVN).
The problem initially reported by Mozilla folks (http://code.google.com/p/address-sanitizer/issues/detail?id=20),
but it also prevents us from enabling LLVM bootstrap with AddressSanitizer.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@149925 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/MemoryDependenceAnalysis.cpp b/lib/Analysis/MemoryDependenceAnalysis.cpp
index 30f8d94..cfaf2da 100644
--- a/lib/Analysis/MemoryDependenceAnalysis.cpp
+++ b/lib/Analysis/MemoryDependenceAnalysis.cpp
@@ -323,6 +323,14 @@
!TD.fitsInLegalInteger(NewLoadByteSize*8))
return 0;
+ if (LIOffs+NewLoadByteSize > MemLocEnd &&
+ LI->getParent()->getParent()->hasFnAttr(Attribute::AddressSafety)) {
+ // We will be reading past the location accessed by the original program.
+ // While this is safe in a regular build, Address Safety analysis tools
+ // may start reporting false warnings. So, don't do widening.
+ return 0;
+ }
+
// If a load of this width would include all of MemLoc, then we succeed.
if (LIOffs+NewLoadByteSize >= MemLocEnd)
return NewLoadByteSize;