Revert commit 131781, to see if it fixes the x86-64 dragonegg buildbot.
Original log message:
When BasicAA can determine that two pointers have the same base but
differ by a dynamic offset, return PartialAlias instead of MayAlias.
See the comment in the code for details. This fixes PR9971.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131809 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/BasicAliasAnalysis.cpp b/lib/Analysis/BasicAliasAnalysis.cpp
index f506608..f1bb8a3 100644
--- a/lib/Analysis/BasicAliasAnalysis.cpp
+++ b/lib/Analysis/BasicAliasAnalysis.cpp
@@ -940,17 +940,7 @@
return NoAlias;
}
- // Statically, we can see that the base objects are the same, but the
- // pointers have dynamic offsets which we can't resolve. And none of our
- // little tricks above worked.
- //
- // TODO: Returning PartialAlias instead of MayAlias is a mild hack; the
- // practical effect of this is protecting TBAA in the case of dynamic
- // indices into arrays of unions. An alternative way to solve this would
- // be to have clang emit extra metadata for unions and/or union accesses.
- // A union-specific solution wouldn't handle the problem for malloc'd
- // memory however.
- return PartialAlias;
+ return MayAlias;
}
/// aliasSelect - Provide a bunch of ad-hoc rules to disambiguate a Select