[llvm] afa192c - [InstCombine] add narrowing transform for low-masked binop with zext operand

[Sanjay Patel via llvm-commits]

Thanks! I reverted and will reduce the test. Most likely, there is an
opposing transform in instcombine.

On Fri, Jun 10, 2022 at 3:05 AM Martin Storsjö <martin at martin.st> wrote:

> On Thu, 9 Jun 2022, Sanjay Patel via llvm-commits wrote:
>
> >
> > Author: Sanjay Patel
> > Date: 2022-06-09T16:59:26-04:00
> > New Revision: afa192cfb6049a15c5542d132d500b910b802c74
> >
> > URL:
> https://github.com/llvm/llvm-project/commit/afa192cfb6049a15c5542d132d500b910b802c74
> > DIFF:
> https://github.com/llvm/llvm-project/commit/afa192cfb6049a15c5542d132d500b910b802c74.diff
> >
> > LOG: [InstCombine] add narrowing transform for low-masked binop with
> zext operand
> >
> > https://alive2.llvm.org/ce/z/hRy3rE
> >
> > As shown in D123408, we can produce this pattern when moving
> > cast around, and we already have a related fold for a binop
> > with a constant operand.
>
> This commit causes breakage for me - one file which used to compile in
> around a second now hangs (doesn't complete in many minutes at least).
>
> To reproduce, download https://martin.st/temp/remap-preproc.c and try to
> compile it with "clang -target x86_64-w64-mingw32 -w -c -O2
> remap-preproc.c".
>
> // Martin
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20220610/b8ce41fa/attachment.html>