DAGCombiner: Relax alignment restriction when changing store type

If the target allows the alignment, this should be OK.

llvm-svn: 267217

1 files changed, 14 insertions, 10 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 690a53e785c..75faf526fab 100644
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -11970,17 +11970,21 @@ SDValue DAGCombiner::visitSTORE(SDNode *N) {
   // resultant store does not need a higher alignment than the original.
   if (Value.getOpcode() == ISD::BITCAST && !ST->isTruncatingStore() &&
       ST->isUnindexed()) {
-    unsigned OrigAlign = ST->getAlignment();
     EVT SVT = Value.getOperand(0).getValueType();
-    unsigned Align = DAG.getDataLayout().getABITypeAlignment(
-        SVT.getTypeForEVT(*DAG.getContext()));
-    if (Align <= OrigAlign &&
-        ((!LegalOperations && !ST->isVolatile()) ||
-         TLI.isOperationLegalOrCustom(ISD::STORE, SVT)))
-      return DAG.getStore(Chain, SDLoc(N), Value.getOperand(0),
-                          Ptr, ST->getPointerInfo(), ST->isVolatile(),
-                          ST->isNonTemporal(), OrigAlign,
-                          ST->getAAInfo());
+    if (((!LegalOperations && !ST->isVolatile()) ||
+         TLI.isOperationLegalOrCustom(ISD::STORE, SVT)) &&
+        TLI.isStoreBitCastBeneficial(Value.getValueType(), SVT)) {
+      unsigned OrigAlign = ST->getAlignment();
+      bool Fast = false;
+      if (TLI.allowsMemoryAccess(*DAG.getContext(), DAG.getDataLayout(), SVT,
+                                 ST->getAddressSpace(), OrigAlign, &Fast) &&
+          Fast) {
+        return DAG.getStore(Chain, SDLoc(N), Value.getOperand(0),
+                            Ptr, ST->getPointerInfo(), ST->isVolatile(),
+                            ST->isNonTemporal(), OrigAlign,
+                            ST->getAAInfo());
+      }
+    }
   }
 
   // Turn 'store undef, Ptr' -> nothing.