[llvm] [X86] getScalarMaskingNode - if the mask is zero just return the preserved source value (PR #153575)

[Phoebe Wang via llvm-commits]

================
@@ -26261,10 +26261,8 @@ static SDValue getScalarMaskingNode(SDValue Op, SDValue Mask,
                                     SDValue PreservedSrc,
                                     const X86Subtarget &Subtarget,
                                     SelectionDAG &DAG) {
-
   if (auto *MaskConst = dyn_cast<ConstantSDNode>(Mask))
-    if (MaskConst->getZExtValue() & 0x1)
-      return Op;
+    return (MaskConst->getZExtValue() & 0x1) ? Op : PreservedSrc;
----------------
phoebewang wrote:

I guess it's not correct. The upper elements in scalar comes from operand 1 instead of `passThru`.

https://github.com/llvm/llvm-project/pull/153575