Restrict FindBetterChain DAG combines to unindexed nodes

These transformations obviously won't work for indexed (pre/post-inc) loads and
stores. In practice, I'm not sure there is any benefit to enabling them for
indexed nodes because other transformations that these might enable likely also
won't handle indexed nodes.

I don't have an in-tree test case that hits this problem, but an upcoming bug
fix will make it much more likely.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200023 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Hal Finkel 2014-01-24 18:25:26 +00:00
parent fb282c68b7
commit 08aa5bf1d5

View File

@ -7729,7 +7729,7 @@ SDValue DAGCombiner::visitLOAD(SDNode *N) {
bool UseAA = CombinerAA.getNumOccurrences() > 0 ? CombinerAA :
TLI.getTargetMachine().getSubtarget<TargetSubtargetInfo>().useAA();
if (UseAA) {
if (UseAA && LD->isUnindexed()) {
// Walk up chain skipping non-aliasing memory nodes.
SDValue BetterChain = FindBetterChain(N, Chain);
@ -9317,7 +9317,7 @@ SDValue DAGCombiner::visitSTORE(SDNode *N) {
bool UseAA = CombinerAA.getNumOccurrences() > 0 ? CombinerAA :
TLI.getTargetMachine().getSubtarget<TargetSubtargetInfo>().useAA();
if (UseAA) {
if (UseAA && ST->isUnindexed()) {
// Walk up chain skipping non-aliasing memory nodes.
SDValue BetterChain = FindBetterChain(N, Chain);