[AVX512] incorrect register in vpbroadcastb instruction

[dbabokin]

Bugzilla Link	33795
Resolution	FIXED
Resolved on	Aug 17, 2017 10:42
Version	trunk
OS	All
Blocks	#33196
Attachments	reproducer
CC	@topperc,@Delena,@zmodem,@igor-breger,@RKSimon,@ZviRackover

Extended Description

clang trunk, x86 (32 bit mode).

Clang generates "vpbroadcastb %ch, %xmm1" instruction (at least it intends doing so). The instruction consumes 8 bit from general purpose register, but only 32 registers are allowed. As a result, clang tries to encode
"vpbroadcastb %ch, %xmm1" as 62 f2 7d 08 7a cd, which really is "vpbroadcastb %ebp,%zmm1".

I assume instruction description is incorrect.

The instruction was generated by "Machine Instruction Scheduler on function" pass, if this matters.

Reproducer isn't really small, check "run" file for instruction for compiling it, they should be self explanatory.

Let me know if more details are needed.

[llvmbot]

fix under review

https://reviews.llvm.org/D36479

[topperc]

Once this is commited should we port to 5.0?

[dbabokin]

Yes, we need it in 5.0. If possible in 4.0 and 3.9. Or I'd like to apply it manually to the version that we build.

[llvmbot]

committed
revision r310498

[topperc]

Hans, can we merge this to 5.0?

[zmodem]

Hans, can we merge this to 5.0?

Sounds good to me. I'll merge after it's baked in trunk a little bit.

[RKSimon]

Hans, can we merge this to 5.0?

Sounds good to me. I'll merge after it's baked in trunk a little bit.

OK to merge? I haven't noticed any related bugs pop up in the past week.

[zmodem]

Hans, can we merge this to 5.0?

Sounds good to me. I'll merge after it's baked in trunk a little bit.

OK to merge? I haven't noticed any related bugs pop up in the past week.

Yes, I've merged it in r311110. Thanks!

[zmodem]

mentioned in issue #33196