[LV] Fix analyzeInterleaving when -pass-remarks enabled

Summary:
If -pass-remarks=loop-vectorize, atomic ops will be seen by
analyzeInterleaving(), even though canVectorizeMemory() == false. This
is because we are requesting extra analysis instead of bailing out.

In such a case, we end up with a Group in both Load- and StoreGroups,
and then we'll try to access freed memory when traversing LoadGroups after having had released the Group when  iterating over StoreGroups.

The fix is to include mayWriteToMemory() when validating that two
instructions are the same kind of memory operation.

Reviewers: mssimpso, davidxl

Reviewed By: davidxl

Subscribers: hsaito, fhahn, llvm-commits

Differential Revision: https://reviews.llvm.org/D43064

llvm-svn: 324786

1 files changed, 6 insertions, 1 deletions

diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
index 973617cc0c7..7f45c7a3571 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -5926,7 +5926,12 @@ void InterleavedAccessInfo::analyzeInterleaving(
 
       // Ignore A if it's already in a group or isn't the same kind of memory
       // operation as B.
-      if (isInterleaved(A) || A->mayReadFromMemory() != B->mayReadFromMemory())
+      // Note that mayReadFromMemory() isn't mutually exclusive to mayWriteToMemory
+      // in the case of atomic loads. We shouldn't see those here, canVectorizeMemory()
+      // should have returned false - except for the case we asked for optimization
+      // remarks.
+      if (isInterleaved(A) || (A->mayReadFromMemory() != B->mayReadFromMemory())
+          || (A->mayWriteToMemory() != B->mayWriteToMemory()))
         continue;
 
       // Check rules 1 and 2. Ignore A if its stride or size is different from