[PATCH] D135541: [TargetLowering][RISCV][X86] Support even divisors in expandDIVREMByConstant.

Mon Oct 24 14:17:14 PDT 2022

mstorsjo added a comment.

In D135541#3879320 <https://reviews.llvm.org/D135541#3879320>, @mstorsjo wrote:

> Thanks for the revert!
>
> I didn’t have time to narrow it down further yet, but it can be reproduced with these steps:
>
>   git clone git://source.ffmpeg.org/ffmpeg
>   cd ffmpeg
>   ./configure --cc=“clang -target …” --samples=$(pwd)/../samples
>   make -j$(nproc)
>   make fate-rsync
>   make fate-sub-lrc-remux
>
> I don’t know yet which object files contain the breakage here.

For this particular testcase, the changed behaviour is in `libavformat/lrcenc.o`.

The changed behaviour can be seen in https://martin.st/temp/lrcenc-preproc.c, compiled with `clang -target i686-w64-mingw32 -c lrcenc-preproc.c -O2`. (I haven't traced the code to see exactly what inputs makes what difference in behaviour though.)

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D135541/new/

https://reviews.llvm.org/D135541