Disable the main feature of 130180, the elimination of loads that are
redundant with partially-aliasing loads.
When computing what portion of a clobbering load value is needed,
it doesn't consider phi-translation which may have occurred
between the clobbing load and the redundant load.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@132631 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/MemoryDependenceAnalysis.cpp b/lib/Analysis/MemoryDependenceAnalysis.cpp
index a412425..5f640c0 100644
--- a/lib/Analysis/MemoryDependenceAnalysis.cpp
+++ b/lib/Analysis/MemoryDependenceAnalysis.cpp
@@ -374,10 +374,16 @@
if (R == AliasAnalysis::MustAlias)
return MemDepResult::getDef(Inst);
+#if 0 // FIXME: Temporarily disabled. GVN is cleverly rewriting loads
+ // in terms of clobbering loads, but since it does this by looking
+ // at the clobbering load directly, it doesn't know about any
+ // phi translation that may have happened along the way.
+
// If we have a partial alias, then return this as a clobber for the
// client to handle.
if (R == AliasAnalysis::PartialAlias)
return MemDepResult::getClobber(Inst);
+#endif
// Random may-alias loads don't depend on each other without a
// dependence.