> -----Original Message----- > From: H.J. Lu <[email protected]> > Sent: Friday, August 7, 2026 4:30 PM > To: Liu, Hongtao <[email protected]> > Cc: Hongtao Liu <[email protected]>; [email protected]; GCC > Patches <[email protected]>; Uros Bizjak <[email protected]>; Jiang, > Haochen <[email protected]> > Subject: [PATCH] x86: Update cpuid.h to pass leaf to __get_cpuid_max > > On Fri, Aug 7, 2026 at 4:13 PM H.J. Lu <[email protected]> wrote: > > > > On Fri, Aug 7, 2026 at 3:14 PM Liu, Hongtao <[email protected]> > wrote: > > > > > > > > > > > > > -----Original Message----- > > > > From: H.J. Lu <[email protected]> > > > > Sent: Friday, August 7, 2026 2:51 PM > > > > To: Hongtao Liu <[email protected]> > > > > Cc: [email protected]; GCC Patches <[email protected]>; > > > > Uros Bizjak <[email protected]>; Liu, Hongtao > > > > <[email protected]>; Jiang, Haochen <[email protected]> > > > > Subject: Re: [PATCH] tree-vect.h: Compile check_vect with -O0 > > > > > > > > On Fri, Aug 7, 2026 at 2:19 PM Hongtao Liu <[email protected]> > wrote: > > > > > > > > > > On Fri, Aug 7, 2026 at 10:59 AM H.J. Lu <[email protected]> wrote: > > > > > > > > > > > > On Fri, Aug 7, 2026 at 6:12 AM H.J. Lu <[email protected]> wrote: > > > > > > > > > > > > > > commit 44cc8e5718efd0cc1ef57c68052dbe33b047f158 > > > > > > > Author: Ewan <[email protected]> > > > > > > > Date: Tue Mar 17 16:12:15 2026 +0800 > > > > > > > > > > > > > > i386: Fix __get_cpuid() and __get_cpuid_count() for > > > > > > > Centaur/Zhaoxin CPUID range > > > > > > > > > > > > > > caused many regressions, like > > > > > > > > > > > > > > FAIL: gcc.dg/vect/vect-100.c scan-tree-dump-not optimized > > > > > > > "Invalid > > > > sum" > > > > > > > > > > > > > > on Linux/x86-64 with -m32. The commit above changed > > > > > > > __get_cpuid_count which is used by check_vect in tree-vect.h. > > > > > > > When GCC tried to vectorize check_vect, it outputted > > > > > > > > > > > > > > __attribute__((noinline)) > > > > > > > void check_vect () > > > > > > > { > > > > > > > ... > > > > > > > ;; Invalid sum of incoming counts 966367640 (estimated locally, > freq > > > > > > > 0.9000), should be 719407024 (estimated locally, freq > > > > > > > 0.6700) > > > > > > > > > > > > > > which failed > > > > > > > > > > > > > > /* { dg-final { scan-tree-dump-not "Invalid sum" "optimized" > > > > > > > } } */ > > > > > > > > > > > > > > Compile check_vect with -O0 to avoid it. > > > > > > > > > > > > > > * gcc.dg/vect/tree-vect.h (check_vect): Compile with -O0. > > > > > > > > > > > > > > > > > > > > > -- > > > > > > > H.J. > > > > > > > > > > > > This fixes: > > > > > > > > > > > > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126697 > > > > > > > > > > Can we use > > > > > > > > > > unsigned int __ext = __leaf & 0xC0000000; > > > > > > > > > > Assume it can also support zhaoxin's maximum secondary extended > > > > > level(0xC0000000);? > > > > > > > > Or we can fold it into __get_cpuid_max. > > > That would be better, then we don't need 2 duplicated parts in > > > __get_cpuid and __get_cpuid_count > > > > > > > Should it be reverted for now and reimplement it in __get_cpuid_max? > > > > Or this patch. @Ewanhai Could you help confirm if this patch can also address the issue for Centaur/Zhaoxin CPUID range?
> > -- > H.J. > --- > commit 44cc8e5718efd0cc1ef57c68052dbe33b047f158 > Author: Ewan <[email protected]> > Date: Tue Mar 17 16:12:15 2026 +0800 > > i386: Fix __get_cpuid() and __get_cpuid_count() for Centaur/Zhaoxin CPUID > ra nge > > caused many regressions, like > > FAIL: gcc.dg/vect/vect-100.c scan-tree-dump-not optimized "Invalid sum" > > on Linux/x86-64 with -m32. The commit above changed __get_cpuid_count > which is used by check_vect in tree-vect.h. When GCC tried to vectorize > check_vect, it outputted > > __attribute__((noinline)) > void check_vect () > { > ... > ;; Invalid sum of incoming counts 966367640 (estimated locally, freq > 0.9000), > should be 719407024 (estimated locally, freq 0.6700) > > which failed > > /* { dg-final { scan-tree-dump-not "Invalid sum" "optimized" } } */ > > Change __get_cpuid and __get_cpuid_count to pass the leaf argument directly > to __get_cpuid_max and apply 0xC0000000 mask before passing it to CPUID. > > PR testsuite/126697 > * config/i386/cpuid.h (__get_cpuid_max): Rename the first argument to > __leaf and apply 0xC0000000 mask before passing it to CPUID. > (__get_cpuid): Pass __leaf to __get_cpuid_max. > (__get_cpuid_count): Likewise.
