[llvm] [X86] Optimized ADD + ADC to ADC (PR #173543)

[Simon Pilgrim via llvm-commits]

================
@@ -58164,6 +58164,16 @@ static SDValue combineX86AddSub(SDNode *N, SelectionDAG &DAG,
     }
   }
 
+  // Fold ADD(ADC(Y, C1, CF), C2) -> ADC(Y, C1 + C2, CF)
----------------
RKSimon wrote:

What if C1+C2 overflow?

https://github.com/llvm/llvm-project/pull/173543