[PATCH] D131672: [instcombine] Optimise for zero initialisation of product given fast flags are enabled

Wed Aug 17 02:35:54 PDT 2022

fhahn accepted this revision.
fhahn added a comment.

LGTM, thanks!

In D131672#3725714 <https://reviews.llvm.org/D131672#3725714>, @spatel wrote:

> LGTM - see inline comment for formatting nit. 
> The tests seem fine too, but let @fhahn have another look in case there are any other suggestions.
>
> I'm not sure what source causes this pattern, but there could be related fast-math simplifications like `X * 1.0 --> X`.

The source was a user report. I am not sure about FMUL recurrences that have 1.0 as start value. But I think we might want the same fold for integer multiply as follow up.

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https://reviews.llvm.org/D131672