[PATCH 3/3] i386: Replace inline asm rotates in pointer_guard with stdc_rotate_{left, right}

[Uros Bizjak]

Use the C23 <stdbit.h> rotation helpers instead of inline assembly
for pointer mangling and demangling on i386.

The PTR_MANGLE and PTR_DEMANGLE macros previously used rol/ror
inline asm with a constant rotation of 9. Replace these with
stdc_rotate_left and stdc_rotate_right operating on uintptr_t,
preserving the exact rotation count via 2 * sizeof (uintptr_t) + 1.

This change removes inline assembly, improves portability and
readability and lets the compiler select optimal code generation.

No functional change intended.

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
---
 sysdeps/unix/sysv/linux/i386/pointer_guard.h | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/sysdeps/unix/sysv/linux/i386/pointer_guard.h b/sysdeps/unix/sysv/linux/i386/pointer_guard.h
index 7c142fb526..c8311be444 100644
--- a/sysdeps/unix/sysv/linux/i386/pointer_guard.h
+++ b/sysdeps/unix/sysv/linux/i386/pointer_guard.h
@@ -33,16 +33,19 @@
 #  define PTR_DEMANGLE(reg)	rorl $9, reg;				      \
 				xorl %gs:POINTER_GUARD, reg
 # else
+#  include <stdbit.h>
 #  include <tls.h>
 #  define PTR_MANGLE(var)						      \
     do {								      \
       (var) = (__typeof (var)) ((uintptr_t) (var)			      \
 				^ ((tcbhead_t __seg_gs *)0)->pointer_guard);  \
-      asm ("roll $9, %0" : "+r" (var));					      \
+      (var) = (__typeof (var)) stdc_rotate_left ((uintptr_t) (var),	      \
+						 2 * sizeof (uintptr_t) + 1); \
     } while (0)
 #  define PTR_DEMANGLE(var)						      \
     do {								      \
-      asm ("rorl $9, %0" : "+r" (var));					      \
+      (var) = (__typeof (var)) stdc_rotate_right ((uintptr_t) (var),	      \
+						  2 * sizeof (uintptr_t) + 1); \
       (var) = (__typeof (var)) ((uintptr_t) (var)			      \
 				^ ((tcbhead_t __seg_gs *)0)->pointer_guard);  \
     } while (0)
-- 
2.54.0