Date: Wed, 31 Dec 2025 13:55:34 -0300
On Wednesday, 31 December 2025 13:44:11 Brasilia Standard Time Thiago Macieira
via Std-Proposals wrote:
> Though for
> this one there is an ABI-changing -m option: -mno-vzeroupper.
Slight correction on myself: VZEROUPPER is not ABI-changing. It merely impacts
on performance if the called code uses register-merging non-AVX instructions,
but the ABI remains.
There are -m options that change ABI. They're all clearly documented as such.
And from my ARM days, I remember -mhard-float.
PS: the VZEROALL instruction does not zero all registers. We joke that it's
"VZEROSOME".
via Std-Proposals wrote:
> Though for
> this one there is an ABI-changing -m option: -mno-vzeroupper.
Slight correction on myself: VZEROUPPER is not ABI-changing. It merely impacts
on performance if the called code uses register-merging non-AVX instructions,
but the ABI remains.
There are -m options that change ABI. They're all clearly documented as such.
And from my ARM days, I remember -mhard-float.
PS: the VZEROALL instruction does not zero all registers. We joke that it's
"VZEROSOME".
-- Thiago Macieira - thiago (AT) macieira.info - thiago (AT) kde.org Principal Engineer - Intel Data Center - Platform & Sys. Eng.
Received on 2025-12-31 16:55:43