[PATCH] D67721: [InstSimplify] fold fma/fmuladd with a NaN operand

Thu Sep 19 04:23:27 PDT 2019

spatel added a comment.

In D67721#1674583 <https://reviews.llvm.org/D67721#1674583>, @fhahn wrote:

>   D67553 adds `SimplifyFMAMul`. We should probably also have them there. Also, could we make use of multiply by 0.0 here, with the required fast-math flags?

Yes, these patches should converge somehow. That's partly why I only put the NaN folding in this one, but if you think it's better to wait for the other patches to land, that's fine with me.
I think we'll end up modifying D67351 <https://reviews.llvm.org/D67351> - if we can fold fma(a,0,b) --> b, then we want that to happen in InstSimplify directly rather than InstCombine because it's more efficient that way.

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