[PATCH] DAGCombiner: Continue combining if FoldConstantArithmetic() fails.

[Matthias Braun]

> On Jan 12, 2015, at 8:02 PM, Ahmed Bougacha <ahmed.bougacha at gmail.com> wrote:
> 
> ================
> Comment at: lib/CodeGen/SelectionDAG/DAGCombiner.cpp:1572
> @@ +1571,3 @@
> +  if (N0C && N1C) {
> +    SDValue Folded = DAG.FoldConstantArithmetic(ISD::ADD, VT, N0C, N1C);
> +    if (Folded.getNode())
> ----------------
> How about:
> 
>    if (SDValue Folded = ...)
>      return Folded;
> 
> Or going further, you could remove the N0C && N1C check, since FoldConstantArithmetic also does it (a sliver more wasteful though).

unfortunately
if ((SDValue Folded = ...).getNode())
    return Folded;
would be necessary and is not valid C++.