CFLAA: return MustAlias when pointers p, q are equal, i.e.,

must-alias(p, sz_p, p, sz_q)  irrespective of access sizes sz_p, sz_q

As discussed a couple of weeks ago on the ML.
This makes the behavior consistent with that of BasicAA.
AA clients already check the obj size themselves and may not require the
obj size to match exactly the access size (e.g., in case of store forwarding)

llvm-svn: 310495

diff --git a/llvm/include/llvm/Analysis/CFLSteensAliasAnalysis.h b/llvm/include/llvm/Analysis/CFLSteensAliasAnalysis.h
index fd3fa5f..03ce85a 100644 (file)
--- a/llvm/include/llvm/Analysis/CFLSteensAliasAnalysis.h
+++ b/llvm/include/llvm/Analysis/CFLSteensAliasAnalysis.h
@@ -68,7 +68,7 @@ public:
 
   AliasResult alias(const MemoryLocation &LocA, const MemoryLocation &LocB) {
     if (LocA.Ptr == LocB.Ptr)
-      return LocA.Size == LocB.Size ? MustAlias : PartialAlias;
+      return MustAlias;
 
     // Comparisons between global variables and other constants should be
     // handled by BasicAA.

diff --git a/llvm/lib/Analysis/CFLAndersAliasAnalysis.cpp b/llvm/lib/Analysis/CFLAndersAliasAnalysis.cpp
index 0de7ad9..1a39988 100644 (file)
--- a/llvm/lib/Analysis/CFLAndersAliasAnalysis.cpp
+++ b/llvm/lib/Analysis/CFLAndersAliasAnalysis.cpp
@@ -837,7 +837,7 @@ AliasResult CFLAndersAAResult::query(const MemoryLocation &LocA,
 AliasResult CFLAndersAAResult::alias(const MemoryLocation &LocA,
                                      const MemoryLocation &LocB) {
   if (LocA.Ptr == LocB.Ptr)
-    return LocA.Size == LocB.Size ? MustAlias : PartialAlias;
+    return MustAlias;
 
   // Comparisons between global variables and other constants should be
   // handled by BasicAA.