On Tue, Oct 22, 2024 at 6:19 PM LIU Hao <[email protected]> wrote:
>
> 在 2024-10-22 22:18, Jacek Caban 写道:
> > Style-wise, I would perhaps prefer a solution that uses fewer #ifdefs. We
> > could for example change
> > __mingw_has_sse to always return true when it's defined. It would limit
> > optimization opportunities
> > for the compiler, so perhaps we could have it in a header and make it a
> > trivial inline in case
> > __SSE__ is defined? Anyway, the current patch matches how similar things
> > are done in mingw-w64, so I
> > won't insist on that.
> >
> >
> > Even with that patch, the original patch caching cpuid result would still
> > be beneficial for cases
> > when __SSE__ is not defined.
>
> Here's an updated patch.
A minor tweak would be like:
if (__has_sse < 0) {
int cpuInfo[4], infoType = 1;
int o_flag, n_flag;
__asm__ volatile ("pushfl\n\tpopl %0" : "=mr" (o_flag));
n_flag = o_flag ^ 0x200000;
__asm__ volatile ("pushl %0\n\tpopfl" : : "g" (n_flag));
__asm__ volatile ("pushfl\n\tpopl %0" : "=mr" (n_flag));
if (n_flag == o_flag) {
__has_sse = 0;
return 0;
}
__asm__ __volatile__ (
"cpuid"
: "=a" (cpuInfo[0]), "=b" (cpuInfo[1]), "=c" (cpuInfo[2]),
"=d" (cpuInfo[3])
: "a" (infoType));
__has_sse = (cpuInfo[3] & 0x2000000);
}
return __has_sse;
--
O.S.
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