[DAGCombine] Pull out repeated demanded bitmask generation. NFCI.

llvm-svn: 355932

1 files changed, 9 insertions, 10 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 8426e3925a1..fc1c97b8e9a 100644
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -15420,23 +15420,22 @@ SDValue DAGCombiner::visitSTORE(SDNode *N) {
       Value.getValueType().isInteger() &&
       (!isa<ConstantSDNode>(Value) ||
        !cast<ConstantSDNode>(Value)->isOpaque())) {
+    APInt TruncDemandedBits =
+        APInt::getLowBitsSet(Value.getScalarValueSizeInBits(),
+                             ST->getMemoryVT().getScalarSizeInBits());
+
     // See if we can simplify the input to this truncstore with knowledge that
     // only the low bits are being used.  For example:
     // "truncstore (or (shl x, 8), y), i8"  -> "truncstore y, i8"
-    SDValue Shorter = DAG.GetDemandedBits(
-        Value, APInt::getLowBitsSet(Value.getScalarValueSizeInBits(),
-                                    ST->getMemoryVT().getScalarSizeInBits()));
+    SDValue Shorter = DAG.GetDemandedBits(Value, TruncDemandedBits);
     AddToWorklist(Value.getNode());
-    if (Shorter.getNode())
-      return DAG.getTruncStore(Chain, SDLoc(N), Shorter,
-                               Ptr, ST->getMemoryVT(), ST->getMemOperand());
+    if (Shorter)
+      return DAG.getTruncStore(Chain, SDLoc(N), Shorter, Ptr, ST->getMemoryVT(),
+                               ST->getMemOperand());
 
     // Otherwise, see if we can simplify the operation with
     // SimplifyDemandedBits, which only works if the value has a single use.
-    if (SimplifyDemandedBits(
-            Value,
-            APInt::getLowBitsSet(Value.getScalarValueSizeInBits(),
-                                 ST->getMemoryVT().getScalarSizeInBits()))) {
+    if (SimplifyDemandedBits(Value, TruncDemandedBits)) {
       // Re-visit the store if anything changed and the store hasn't been merged
       // with another node (N is deleted) SimplifyDemandedBits will add Value's
       // node back to the worklist if necessary, but we also need to re-visit