[PATCH] D80801: [DAGCombiner] allow more folding of fadd + fmul into fma

[Bryan Chan via Phabricator via llvm-commits]

bryanpkc added a comment.

In D80801#2102291 <https://reviews.llvm.org/D80801#2102291>, @efriedma wrote:

> > We are only pulling the trailing addition in with an existing multiply.
>
> The problem here is that it's the "wrong" multiply: you have, essentially `(A*B+D*E)+F`, and you're turning it into `A*B+(D*E+F)`.  I don't think contraction is supposed to cover that.


That is exactly my concern; I was under the impression that contraction only allowed fusing `(A*B+C)` and nothing else.


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