[PATCH] D61802: [LoopVectorize] Enable float minmax reductions via instruction flag

[Sanjay Patel via Phabricator via llvm-commits]

spatel added a comment.

In D61802#1798626 <https://reviews.llvm.org/D61802#1798626>, @nlw0 wrote:

> Hi, I'm unable to spend much time on this right now, although I'm definitely still interested.
>
> On Julia the IR is currently generated with flags in the fcmp instruction. I was hoping at first that this would just work like that, although now it sounds like there will need to be changes on how this IR is being produced in the first place. What is the way forward?


The current thinking is that we want any FP value to be able to carry fast-math-flag properties. That would hopefully remove logical inconsistencies such as shown here:
https://bugs.llvm.org/show_bug.cgi?id=38086

We've made some progress towards that goal by allowing FMF on select and phi instructions. Originally, I thought that just adding FMF to select/phi would be enough to fix this. But it seems clear now that we're going to need to allow FMF on memory ops and probably on function arguments before we can deprecate FMF on fcmp.


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  rL LLVM

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  https://reviews.llvm.org/D61802/new/

https://reviews.llvm.org/D61802