[llvm] [SDAG] Turn umin into smin if the saturation pattern is broken (PR #88505)

[Simon Pilgrim via llvm-commits]

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@@ -5589,7 +5592,7 @@ SDValue DAGCombiner::visitIMINMAX(SDNode *N) {
     case ISD::UMAX: AltOpcode = ISD::SMAX; break;
     default: llvm_unreachable("Unknown MINMAX opcode");
     }
-    if (TLI.isOperationLegal(AltOpcode, VT))
+    if (IsSatBroken || TLI.isOperationLegal(AltOpcode, VT))
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RKSimon wrote:

Should we limit this to `(!LegalOperations && IsSatBroken) || TLI.isOperationLegal(AltOpcode, VT)`?

https://github.com/llvm/llvm-project/pull/88505