[llvm] [WebAssembly] Fix missed optimization in 50142 (PR #144741)

[Sam Parker via llvm-commits]

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@@ -3248,6 +3248,37 @@ static SDValue performSETCCCombine(SDNode *N,
   ISD::CondCode Cond = cast<CondCodeSDNode>(N->getOperand(2))->get();
   SDLoc DL(N);
   EVT VT = N->getValueType(0);
+  //  N           LHS     LhsL        LhsLL    LhsLR   InnerCond RHS Cond
+  // setcc (iN (bitcast (setcc vNi1 (vNiY X), <vNiY 0>, eq)),     0, eq
+  // => all_true (vNi1 X)
+  if (DCI.isBeforeLegalize() && VT.isScalarInteger() && (Cond == ISD::SETEQ) &&
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sparker-arm wrote:

I found it somewhat painful to read the existing code, for which I have now suggested a refactor in #144875 144875.

https://github.com/llvm/llvm-project/pull/144741