[llvm] [X86] Use an FP-based expansion for v4i32 ctlz on SSE2-only targets (PR #167034)

[Matt Arsenault via llvm-commits]

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@@ -29039,6 +29045,13 @@ static SDValue LowerVectorCTLZ(SDValue Op, const SDLoc &DL,
   if (VT.is512BitVector() && !Subtarget.hasBWI())
     return splitVectorIntUnary(Op, DAG, DL);
 
+  if (VT == MVT::v4i32 && Subtarget.hasSSE2() && !Subtarget.hasSSSE3()) {
+    const TargetLowering &TLI = DAG.getTargetLoweringInfo();
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arsenm wrote:

```suggestion
```

https://github.com/llvm/llvm-project/pull/167034