[llvm] [X86] Distribute Certain Bitwise Operations over SELECT (PR #136555)

[Simon Pilgrim via llvm-commits]

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@@ -35552,8 +35553,24 @@ bool X86TargetLowering::isNarrowingProfitable(SDNode *N, EVT SrcVT,
 bool X86TargetLowering::shouldFoldSelectWithIdentityConstant(
     unsigned BinOpcode, EVT VT, unsigned SelectOpcode, SDValue X,
     SDValue Y) const {
-  if (SelectOpcode != ISD::VSELECT)
+  if (SelectOpcode == ISD::SELECT) {
+    if (VT.isVector())
+      return false;
+    if (!Subtarget.hasBMI() || (VT != MVT::i32 && VT != MVT::i64))
+      return false;
+    using namespace llvm::SDPatternMatch;
+    // BLSI
+    if (BinOpcode == ISD::AND && sd_match(Y, m_Neg(m_Specific(X))))
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RKSimon wrote:

can't `sd_match(X, m_Neg(m_Specific(Y)))` occur as well?

https://github.com/llvm/llvm-project/pull/136555