[LLVM 13] Backport D109203

[vchuravy]

Bugzilla Link	51810
Resolution	FIXED
Resolved on	Sep 10, 2021 09:32
Version	trunk
OS	All
Blocks	#50580
CC	@andykaylor,@phoebewang,@tstellar
Fixed by commit(s)	ae8507b 77f2430

Extended Description

Would be nice to backport https://reviews.llvm.org/D109203 landed as https://reviews.llvm.org/rGae8507b0df738205a6b9e3795ad34672b7499381

[vchuravy]

assigned to @topperc

[tstellar]

Craig, Andy what do you think about this?

[andykaylor]

It looks reasonable to me, but I'm not familiar with the problem this was fixing. I'm adding Pengfei, as he reviewed the original patch and should know more.

[phoebewang]

This patch has low risk since it only changes for 32 bits, which is indeed a bug for the use of r11d.
@​Valentin, it should be better if you can provide some background, e.g, if there's a real case that failed for it and this patch works for that case.

[vchuravy]

Yes we hit this reliably with our test suite for Julia. As usual we can carry the patch, but since it is straightforward, back porting it would be nice.

[phoebewang]

Thanks Valentin. I think it's OK to backport.

[tstellar]

Merged: 77f2430