[PATCH] D31726: AliasAnalysis: Be less conservative about volatile than atomic.

Daniel Berlin via Phabricator via llvm-commits llvm-commits at lists.llvm.org
Wed Apr 5 14:52:34 PDT 2017


dberlin updated this revision to Diff 94286.
dberlin added a comment.

- Update patch for now-passing newgvn test


https://reviews.llvm.org/D31726

Files:
  lib/Analysis/AliasAnalysis.cpp
  test/Transforms/NewGVN/volatile-nonvolatile.ll


Index: test/Transforms/NewGVN/volatile-nonvolatile.ll
===================================================================
--- test/Transforms/NewGVN/volatile-nonvolatile.ll
+++ test/Transforms/NewGVN/volatile-nonvolatile.ll
@@ -1,4 +1,3 @@
-; XFAIL: *
 ; RUN: opt -tbaa -newgvn -S < %s | FileCheck %s
 
 %struct.t = type { i32* }
Index: lib/Analysis/AliasAnalysis.cpp
===================================================================
--- lib/Analysis/AliasAnalysis.cpp
+++ lib/Analysis/AliasAnalysis.cpp
@@ -332,23 +332,22 @@
 
 ModRefInfo AAResults::getModRefInfo(const LoadInst *L,
                                     const MemoryLocation &Loc) {
-  // Be conservative in the face of volatile/atomic.
-  if (!L->isUnordered())
+  // Be conservative in the face of atomic.
+  if (isStrongerThan(L->getOrdering(), AtomicOrdering::NotAtomic))
     return MRI_ModRef;
 
   // If the load address doesn't alias the given address, it doesn't read
   // or write the specified memory.
   if (Loc.Ptr && !alias(MemoryLocation::get(L), Loc))
     return MRI_NoModRef;
-
   // Otherwise, a load just reads.
   return MRI_Ref;
 }
 
 ModRefInfo AAResults::getModRefInfo(const StoreInst *S,
                                     const MemoryLocation &Loc) {
-  // Be conservative in the face of volatile/atomic.
-  if (!S->isUnordered())
+    // Be conservative in the face of atomic.
+  if (isStrongerThan(S->getOrdering(), AtomicOrdering::NotAtomic))
     return MRI_ModRef;
 
   if (Loc.Ptr) {


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