[llvm] [X86] Combine `store + vselect` to `masked_store` (PR #145176)

[Simon Pilgrim via llvm-commits]

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@@ -53403,6 +53404,76 @@ static SDValue combineMaskedStore(SDNode *N, SelectionDAG &DAG,
   return SDValue();
 }
 
+static SDValue foldToMaskedStore(StoreSDNode *Store, SelectionDAG &DAG,
+                                 const SDLoc &Dl,
+                                 const X86Subtarget &Subtarget) {
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RKSimon wrote:

OK - but there doesn't seem to be any reason for this to be in X86ISelLowering and not DAGCombiner::visitSTORE - the Subtarget checks looks to be unnecessary based on the ISD::MSTORE legality checks below

https://github.com/llvm/llvm-project/pull/145176