[llvm] [X86] LowerSelect - generalize "select icmp(x,0), lhs, rhs" folding patterns. (PR #107272)

[Simon Pilgrim via llvm-commits]

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@@ -24278,6 +24295,13 @@ SDValue X86TargetLowering::LowerSELECT(SDValue Op, SelectionDAG &DAG) const {
       isOneConstant(Cond.getOperand(1)))
     Cond = Cond.getOperand(0);
 
+  // Attempt to fold "raw cond" cases by treating them as
+  // (select (and X, 1), Op1, Op2  --> (select (icmpeq (and X, 1), 0), Op2, Op1)
+  if (Cond.getOpcode() == ISD::AND && isOneConstant(Cond.getOperand(1)))
+    if (SDValue R = LowerSELECTWithCmpZero(Cond, Op2, Op1, X86::COND_E, DL, DAG,
+                                           Subtarget))
+      return R;
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RKSimon wrote:

#107374

https://github.com/llvm/llvm-project/pull/107272