RE: [PATCH] x86: Compile PR 88465 tests with -mtune=generic

> -----Original Message-----
> From: H.J. Lu <[email protected]>
> Sent: Thursday, August 20, 2026 9:47 AM
> To: GCC Patches <[email protected]>; Uros Bizjak
> <[email protected]>; Liu, Hongtao <[email protected]>
> Subject: [PATCH] x86: Compile PR 88465 tests with -mtune=generic
> 
> Compile PR 88465 tests with -mtune=generic to avoid
> 
> FAIL: gcc.target/i386/avx512bw-pr88465.c scan-assembler-times
> kxnor[dq][ \t] 2
> FAIL: gcc.target/i386/avx512dq-pr88465.c scan-assembler-times kxnorb[ \t]
> 1
> FAIL: gcc.target/i386/avx512f-pr88465.c scan-assembler-times kxnorw[ \t] 1
> 
> caused by different code sequence from different default cost models.

It looks like an mis-optimization under tune=znver4, I check -mtune=sapphirerapids is ok.
Assume kxnorb should be fastest way to move -1 to k register, not load it from constant pool.

> 
> PR testsuite/126923
> * gcc.target/i386/avx512bw-pr88465.c (dg-options): Add -mtune=generic.
> * gcc.target/i386/avx512dq-pr88465.c (dg-options): Likewise.
> * gcc.target/i386/avx512f-pr88465.c (dg-options): Likewise.
> 
> --
> H.J.