[PATCH] D26169: [Reassociate] Skip reassociation for IV if its def instruction contains NSW/NUW flags to enable better IndVar and LSR

[Daniel Berlin via llvm-commits]

Slightly longer term question:
We already kind of know the existing reassociation is a mess.
I'm really curious who the current set of users is supposed to be ;)
(IE at one point it was GVN, but the reassociation done in that pass is
trivial to integrate directly into GVN in a way that doesn't have these bad
effects for later passes, because we can do it virtually instead of by
actually reorging IR)

On Tue, Nov 8, 2016 at 8:07 PM, Mehdi AMINI <mehdi.amini at apple.com> wrote:

> mehdi_amini added a comment.
>
> What about having two modes for reassociate: one where we don't do any
> transformation that drop nsw/nuw flag, and another where it is permitted.
> Depending on the position in the pipeline we allow or not to drop the flags.
>
>
> Repository:
>   rL LLVM
>
> https://reviews.llvm.org/D26169
>
>
>
>
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