[llvm] [DAG] visitFREEZE - always allow freezing multiple operands (PR #145939)

[Simon Pilgrim via llvm-commits]

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@@ -5555,6 +5555,23 @@ bool SelectionDAG::canCreateUndefOrPoison(SDValue Op, const APInt &DemandedElts,
   case ISD::SPLAT_VECTOR:
     return false;
 
+  case ISD::ADDC:
+  case ISD::SUBC:
+  case ISD::ADDE:
+  case ISD::SUBE:
+  case ISD::SADDO:
+  case ISD::SSUBO:
+  case ISD::SMULO:
+  case ISD::SADDO_CARRY:
+  case ISD::SSUBO_CARRY:
+  case ISD::UADDO:
+  case ISD::USUBO:
+  case ISD::UMULO:
+  case ISD::UADDO_CARRY:
+  case ISD::USUBO_CARRY:
+    // No poison on result or overflow flags.
+    return false;
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RKSimon wrote:

sure, although I haven't tried to create standalone test cases yet - I'm still hoping to reduce the regressions with further yak shaving.

https://github.com/llvm/llvm-project/pull/145939