[PATCH] D20845: DAGCombiner: Fix broken check in isAlias

[Matt Arsenault via llvm-commits]

arsenm created this revision.
arsenm added a subscriber: llvm-commits.

This should have been converting the size to bytes, but wasn't really.
These should probably all be using getStoreSize instead.
    
I haven't been able to come up with a meaningful testcase for this.
I can trigger it using combinations of struct loads and stores,
but can't observe a difference in non-broken testcases.
    
isAlias is only really used during store merging, so I'm not sure how
to get into the vector splitting situation the comment describes
since store merging is only done before type legalization.

http://reviews.llvm.org/D20845

Files:
  lib/CodeGen/SelectionDAG/DAGCombiner.cpp

Index: lib/CodeGen/SelectionDAG/DAGCombiner.cpp
===================================================================
--- lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -14731,7 +14731,7 @@
       (Op0->getSrcValueOffset() != Op1->getSrcValueOffset()) &&
       (Op0->getMemoryVT().getSizeInBits() >> 3 ==
        Op1->getMemoryVT().getSizeInBits() >> 3) &&
-      (Op0->getOriginalAlignment() > Op0->getMemoryVT().getSizeInBits()) >> 3) {
+      (Op0->getOriginalAlignment() > (Op0->getMemoryVT().getSizeInBits() >> 3))) {
     int64_t OffAlign1 = Op0->getSrcValueOffset() % Op0->getOriginalAlignment();
     int64_t OffAlign2 = Op1->getSrcValueOffset() % Op1->getOriginalAlignment();
 


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D20845.59159.patch
Type: text/x-patch
Size: 728 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20160601/8debb004/attachment.bin>