[Bug target/120840] Functions with no_callee_saved_registers attribute should preserve frame pointer

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120840

H.J. Lu <hjl.tools at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|[16 Regression] CPython     |Functions with
                   |miscompiled with            |no_callee_saved_registers
                   |preserve_none               |attribute should preserve
                   |                            |frame pointer

--- Comment #13 from H.J. Lu <hjl.tools at gmail dot com> ---
Functions with no_callee_saved_registers attribute should preserve frame
pointer:

[hjl@gnu-zen4-1 pr120840]$ cat pr120840-1a.c 
/* { dg-do run } */
/* { dg-options "-save-temps -O2 -fno-omit-frame-pointer
-mtune-ctrl=prologue_using_move,epilogue_using_move,use_leave" } */

#ifndef DONT_SAVE_REGS1
# define DONT_SAVE_REGS1 __attribute__((no_callee_saved_registers))
#endif
#ifndef DONT_SAVE_REGS2
# define DONT_SAVE_REGS2 __attribute__((no_callee_saved_registers))
#endif

/* Keep labels and directives ('.cfi_startproc', '.cfi_endproc').  */
/* { dg-final { check-function-bodies "**" "" "" { target "*-*-linux*" }
{^\t?\.}  } } */

/*
**do_test:
**.LFB[0-9]+:
**...
**      leave
**...
**      ret
**...
*/

#include <stdlib.h>

DONT_SAVE_REGS1
__attribute__ ((weak, __optimize__ ("-fomit-frame-pointer")))
void
continuation (int arg1, int arg2, int arg3, int arg4, int arg5, int arg6)
{
  /* Clobber frame_pointer register.  */
  asm ("xor %%ebp, %%ebp" ::: "ebp");

  if (arg1 != 17)
    abort ();
  if (arg2 != 8)
    abort ();
  if (arg3 != 20)
    abort ();
  if (arg4 != -3)
    abort ();
  if (arg5 != -4)
    abort ();
  if (arg6 != 26)
    abort ();
}

DONT_SAVE_REGS2
__attribute__ ((weak, __optimize__ ("-fomit-frame-pointer")))
void
entry (int arg1, int arg2, int arg3, int arg4, int arg5, int arg6)
{
  /* Clobber frame_pointer register.  */
  asm ("xor %%ebp, %%ebp" ::: "ebp");

  if (arg1 != 17)
    abort ();
  if (arg2 != 8)
    abort ();
  if (arg3 != 20)
    abort ();
  if (arg4 != -3)
    abort ();
  if (arg5 != -4)
    abort ();
  if (arg6 != 26)
    abort ();
  continuation (arg1, arg2, arg3, arg4, arg5, arg6);
}

__attribute__ ((weak))
void
do_test (void)
{
  entry (17, 8, 20, -3, -4, 26);
}

int
main (void)
{
  do_test ();
  return 0;
}
[hjl@gnu-zen4-1 pr120840]$ make x CC=/usr/gcc-14.2.1-x32/bin/gcc
/usr/gcc-14.2.1-x32/bin/gcc -O2 -fno-omit-frame-pointer
-mtune-ctrl=prologue_using_move,epilogue_using_move -o x pr120840-1a.c
[hjl@gnu-zen4-1 pr120840]$ ./x
Segmentation fault (core dumped)
[hjl@gnu-zen4-1 pr120840]$