[llvm] [AArch64] Combine signext_inreg of setcc(... != splat(0)) (PR #157665)

[David Sherwood via llvm-commits]

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@@ -26097,6 +26097,17 @@ static SDValue performSetCCPunpkCombine(SDNode *N, SelectionDAG &DAG) {
   return SDValue();
 }
 
+static bool isSignExtInReg(const SDValue &V) {
+  if (V.getOpcode() != AArch64ISD::VASHR ||
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david-arm wrote:

I'm hoping that we can encourage all paths into a canonical form that requires a single DAG combine. Your PR may effectively be doing that, just at the very last DAG combiner pass.

https://github.com/llvm/llvm-project/pull/157665