[llvm] [DAG] SelectionDAG::canCreateUndefOrPoison - add ISD::SCMP/UCMP handling + tests (PR #154127)

[Simon Pilgrim via llvm-commits]

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@@ -1036,4 +1107,4 @@ define void @pr59676_nsw(ptr %dst, i32 %x) {
   %div = sdiv i32 %area, 42
   store i32 %div, ptr %dst, align 4
   ret void
-}
+}
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RKSimon wrote:

undo this

https://github.com/llvm/llvm-project/pull/154127