[gcc r17-3274] x86: Update cpuid.h to pass leaf to __get_cpuid_max

https://gcc.gnu.org/g:d0aa6740323e48d4b3743dc8fcd5c0ff552f86d1

commit r17-3274-gd0aa6740323e48d4b3743dc8fcd5c0ff552f86d1
Author: H.J. Lu <[email protected]>
Date:   Fri Aug 7 16:21:54 2026 +0800

    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]>

Diff:
---
 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 129531dcc382..5e1aad57d40d 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;