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. -- 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.
From af8f21ea65f501f76d68ca00e421e814cd0d68ac Mon Sep 17 00:00:00 2001 From: "H.J. Lu" <[email protected]> Date: Fri, 7 Aug 2026 16:21:54 +0800 Subject: [PATCH] x86: Update cpuid.h to pass leaf to __get_cpuid_max 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. Signed-off-by: H.J. Lu <[email protected]> --- gcc/config/i386/cpuid.h | 33 ++++++--------------------------- 1 file changed, 6 insertions(+), 27 deletions(-) diff --git a/gcc/config/i386/cpuid.h b/gcc/config/i386/cpuid.h index 129531dcc38..5e1aad57d40 100644 --- a/gcc/config/i386/cpuid.h +++ b/gcc/config/i386/cpuid.h @@ -270,8 +270,8 @@ : "0" (level), "2" (count)) -/* Return highest supported input value for cpuid instruction. ext can - be either 0x0, 0x40000000, 0x80000000, or 0xC0000000 to return +/* Return highest supported input value for cpuid instruction. leaf can + be either 0xXXX, 0x40000XXX, 0x80000XXX, or 0xC000XXX to return highest supported value for basic, hypervisor, extended, or Centaur/Zhaoxin cpuid information. Function returns 0 if cpuid is not supported or whatever cpuid returns in eax register. If sig @@ -279,9 +279,10 @@ (as found in ebx register) are returned in location pointed by sig. */ static __inline unsigned int -__get_cpuid_max (unsigned int __ext, unsigned int *__sig) +__get_cpuid_max (unsigned int __leaf, unsigned int *__sig) { unsigned int __eax, __ebx, __ecx, __edx; + unsigned int __ext = __leaf & 0xC0000000; #ifndef __x86_64__ /* See if we can use cpuid. On AMD64 we always can. */ @@ -338,18 +339,7 @@ __get_cpuid (unsigned int __leaf, unsigned int *__eax, unsigned int *__ebx, unsigned int *__ecx, unsigned int *__edx) { - unsigned int __ext; - - if (__leaf >= 0xC0000000) - __ext = 0xC0000000; - else if (__leaf >= 0x80000000) - __ext = 0x80000000; - else if (__leaf >= 0x40000000) - __ext = 0x40000000; - else - __ext = 0x00000000; - - unsigned int __maxlevel = __get_cpuid_max (__ext, 0); + unsigned int __maxlevel = __get_cpuid_max (__leaf, 0); if (__maxlevel == 0 || __maxlevel < __leaf) return 0; @@ -365,18 +355,7 @@ __get_cpuid_count (unsigned int __leaf, unsigned int __subleaf, unsigned int *__eax, unsigned int *__ebx, unsigned int *__ecx, unsigned int *__edx) { - unsigned int __ext; - - if (__leaf >= 0xC0000000) - __ext = 0xC0000000; - else if (__leaf >= 0x80000000) - __ext = 0x80000000; - else if (__leaf >= 0x40000000) - __ext = 0x40000000; - else - __ext = 0x00000000; - - unsigned int __maxlevel = __get_cpuid_max (__ext, 0); + unsigned int __maxlevel = __get_cpuid_max (__leaf, 0); if (__builtin_expect (__maxlevel == 0, 0) || __maxlevel < __leaf) return 0; -- 2.55.0
