[Bug target/63890] [4.9/5 regression] Compiling trivial program with -O -p leads to misaligned stack

[hubicka at ucw dot cz]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63890

--- Comment #11 from Jan Hubicka <hubicka at ucw dot cz> ---
> 
> Index: config/i386/i386.h
> ===================================================================
> --- config/i386/i386.h    (revision 220946)
> +++ config/i386/i386.h    (working copy)
> @@ -1606,7 +1606,7 @@ enum reg_class
> 
>  #define ACCUMULATE_OUTGOING_ARGS \
>    ((TARGET_ACCUMULATE_OUTGOING_ARGS && optimize_function_for_speed_p (cfun)) \
> -   || TARGET_STACK_PROBE || TARGET_64BIT_MS_ABI)
> +   || TARGET_STACK_PROBE || TARGET_64BIT_MS_ABI || crtl->profile)

I do not see how ACCUMULATE_OUTGOING_ARGS is going to ensure mcount stack
alignment.
the calls are output into assembly code by:
/* Output assembler code to FILE to increment profiler label # LABELNO          
   for profiling a function entry.  */                                          
void                                                                            
x86_function_profiler (FILE *file, int labelno ATTRIBUTE_UNUSED)                
{                                                                               
  const char *mcount_name = (flag_fentry ? MCOUNT_NAME_BEFORE_PROLOGUE          
                                         : MCOUNT_NAME);                        
  if (TARGET_64BIT)                                                             
    {                                                                           
#ifndef NO_PROFILE_COUNTERS                                                     
      fprintf (file, "\tleaq\t%sP%d(%%rip),%%r11\n", LPREFIX, labelno);         
#endif                                                                          

      if (!TARGET_PECOFF && flag_pic)                                           
        fprintf (file, "1:\tcall\t*%s@GOTPCREL(%%rip)\n", mcount_name);         
      else                                                                      
        x86_print_call_or_nop (file, mcount_name);                              
    }                                                                           

that does not care about ACCUMULATE_OUTGOING_ARGS.  We basically get alignment
by accident because we push RBP.  

My guess is that you want to bump crtl->stack_alignment_needed to 64bits for
every function with crtl->profile