[ARM][DAG] Reenable post-legalize store merge

Summary: Reenable post-legalize stores with constant merging computation and cofrresponding test case.

Reviewers: eastig, efriedma

Subscribers: aemerson, javed.absar, kristof.beyls, hiraditya, llvm-commits

Differential Revision: https://reviews.llvm.org/D40701

llvm-svn: 319547

1 files changed, 11 insertions, 5 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 4d7af07fb93..f04010abb46 100644
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -12636,9 +12636,10 @@ bool DAGCombiner::MergeStoresOfConstantsOrVecElts(
                       ElementSizeBits),
                   SDLoc(CFP), IntMemVT);
             else if (auto *C = dyn_cast<ConstantSDNode>(Val))
-              Val = DAG.getConstant(
-                  C->getAPIntValue().zextOrTrunc(ElementSizeBits),
-                  SDLoc(C), IntMemVT);
+              Val = DAG.getConstant(C->getAPIntValue()
+                                        .zextOrTrunc(Val.getValueSizeInBits())
+                                        .zextOrTrunc(ElementSizeBits),
+                                    SDLoc(C), IntMemVT);
           }
           // Make sure correctly size type is the correct type.
           Val = DAG.getBitcast(MemVT, Val);
@@ -12701,9 +12702,14 @@ bool DAGCombiner::MergeStoresOfConstantsOrVecElts(
       SDValue Val = St->getValue();
       StoreInt <<= ElementSizeBits;
       if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Val)) {
-        StoreInt |= C->getAPIntValue().zextOrTrunc(SizeInBits);
+        StoreInt |= C->getAPIntValue()
+                        .zextOrTrunc(ElementSizeBits)
+                        .zextOrTrunc(SizeInBits);
       } else if (ConstantFPSDNode *C = dyn_cast<ConstantFPSDNode>(Val)) {
-        StoreInt |= C->getValueAPF().bitcastToAPInt().zextOrTrunc(SizeInBits);
+        StoreInt |= C->getValueAPF()
+                        .bitcastToAPInt()
+                        .zextOrTrunc(ElementSizeBits)
+                        .zextOrTrunc(SizeInBits);
       } else {
         llvm_unreachable("Invalid constant element type");
       }