On Mon, Feb 24, 2025 at 10:46:42AM +0100, Attila Szegedi wrote:
> Hi folks,
Hi,
I've been pointed at this thread due to the reference to my Linux patch
series fixing some KVM FPSIMD/SVE/SME issues.
> I'm looking for a bit of a historic context for a fun GCC behavior we
> stumbled across. For...
On Tue, Apr 05, 2022 at 01:51:30PM +0100, Mark Rutland wrote:
> Hi all,
>
> [adding kernel folk who work on asm stuff]
>
> As a heads-up, GCC 12 (not yet released) appears to erroneously optimize away
> calls to functions with volatile asm. Szabolcs has raised an issue on the GCC
> bugzilla:
>
On Tue, Apr 05, 2022 at 04:05:22PM +0200, Peter Zijlstra wrote:
> On Tue, Apr 05, 2022 at 01:51:30PM +0100, Mark Rutland wrote:
> > Hi all,
> >
> > [adding kernel folk who work on asm stuff]
> >
> > As a heads-up, GCC 12 (not yet released) appears to erroneously optimize
> > away
> > calls to fu
Sorry, I copied the wrong version of the x86_64 assembly as generated by GCC
11.2.0). Updated below.
On Tue, Apr 05, 2022 at 01:51:30PM +0100, Mark Rutland wrote:
> My x86_64 test case is:
>
> | unsigned long rdmsr(unsigned long reg)
> | {
> | unsigned int lo, hi;
> |
> | asm volatile(
>
Hi all,
[adding kernel folk who work on asm stuff]
As a heads-up, GCC 12 (not yet released) appears to erroneously optimize away
calls to functions with volatile asm. Szabolcs has raised an issue on the GCC
bugzilla:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105160
... which is a P1 rele
Hi Jeremy,
Thanks for raising this.
On Fri, Apr 01, 2022 at 11:44:06AM -0500, Jeremy Linton wrote:
> The relaxed variants of read/write macros are only declared
> as `asm volatile()` which forces the compiler to generate the
> instruction in the code path as intended. The only problem
> is that i
