Re: [new-regalloc] Problem on x86 with initialization of ra_reg_info

[Daniel Berlin <dberlin at redhat dot com>]

On Fri, 2 Feb 2001, Geert Bosch wrote:

> Actually, I found that the problem that was holding me up was
> that in make_worklist the code clears a bit at a time while traversing
> the set. This doesn't work, as the traversing code assumes a constant
> datastructure. It is also not necessary, as we can just clean the
> set at once at the end, as we'll reset all bits anyway.

Sigh. This works on sbitmaps.
I'm guessing the reason is that the entire word becomes free, so it frees
the ptr element, screwing the traversal.
otherwise, it would work.

It's a good thing the semantics and guarantees of these structures aren't
written down, or else i could have noticed this.


>
> I added a patch for this at the end. This patch also includes a
> static debug_msg routine that does the debug output if necessary.
> I'd really like to use this instead of having all if-statements,
> as they hurt readability of otherwise very readable code.
Works for me.

Do you have commit access, or should I apply this?

Check that, i'll commit it, i also have to take care of a similar problem
in adjacent.
>
>   -Geert
>
> Index: new-regalloc.c
> ===================================================================
> RCS file: /cvs/gcc/gcc/gcc/Attic/new-regalloc.c,v
> retrieving revision 1.1.2.11
> diff -c -r1.1.2.11 new-regalloc.c
> *** new-regalloc.c	2001/02/02 06:01:14	1.1.2.11
> --- new-regalloc.c	2001/02/03 00:42:48
> ***************
> *** 176,181 ****
> --- 176,183 ----
>   	}						\
>     } while (0)
>
> + static void debug_msg PARAMS ((int, const char * , ...)) ATTRIBUTE_PRINTF_2;
> +
>   /* XXX:Extra regset routine, move into bitmap.c??? */
>   static int regset_first_set_bit PARAMS((regset));
>
> ***************
> *** 514,519 ****
> --- 516,544 ----
>   /* Whether to use biased coloring or not */
>   static int biased_coloring = 0;
>
> + /* Print a message to the dump file, if debug_new_regalloc the
> +    same or greater than the specified level. */
> +
> + static void
> + debug_msg VPARAMS ((int level, const char *format, ...))
> + {
> + #ifndef ANSI_PROTOTYPES
> +   int level;
> +   const char *format;
> + #endif
> +   va_list ap;
> +   if (debug_new_regalloc >= level && rtl_dump_file != NULL)
> +     {
> +       VA_START (ap, format);
> +
> + #ifndef ANSI_PROTOTYPES
> +       format = va_arg (ap, const char *);
> + #endif
> +
> +       vfprintf (rtl_dump_file, format, ap);
> +       va_end (ap);
> +     }
> + }
>
>
>   static int
> ***************
> *** 687,726 ****
>
>   /* Make the worklists from the inital set of candidates.  */
>   static void
> ! make_worklist (set)
> !      regset set;
>   {
> !   unsigned int entry;
> !
> !   EXECUTE_IF_SET_IN_REG_SET (set, 0, entry,
> !     {
> !       unsigned int reg_num = entry;
>
> !       /* Remove it from the initial set */
> !       CLEAR_REGNO_REG_SET (set, entry);
>
>         /* If it's of significant degree, place it on the spill_worklist.  */
>         if (ra_reg_info[reg_num]->degree >= reg_freedom (reg_num))
>   	{
> ! 	  if (rtl_dump_file != NULL && debug_new_regalloc > 1)
> ! 	    fprintf (rtl_dump_file, "Inserting %d onto spill_worklist\n", reg_num);
>   	  SET_REGNO_REG_SET (spill_worklist, reg_num);
>   	}
>         /* If it's move related, put it on the freeze worklist.  */
>         else if (move_related (reg_num))
>   	{
> ! 	  if (rtl_dump_file != NULL && debug_new_regalloc > 1)
> ! 	    fprintf (rtl_dump_file, "Inserting %d onto freeze_worklist\n", reg_num);
>   	  SET_REGNO_REG_SET (freeze_worklist, reg_num);
>   	}
>         /* Otherwise, put it on the simplify worklist.  */
>         else
>   	{
> ! 	  if (rtl_dump_file != NULL && debug_new_regalloc > 1)
> ! 	    fprintf (rtl_dump_file, "Inserting %d onto simplify_worklist\n", reg_num);
>   	  SET_REGNO_REG_SET (simplify_worklist, reg_num);
>   	}
>       });
>   }
>
>   /* Returns 1 if the varray contains the register reg_num.  */
> --- 712,748 ----
>
>   /* Make the worklists from the inital set of candidates.  */
>   static void
> ! make_worklist (initial)
> !      regset initial;
>   {
> !   unsigned int reg_num;
>
> !   /* Loop over all candidates in the initial set, starting with 0,
> !      setting reg_num to the register number and executing the block.  */
>
> +   EXECUTE_IF_SET_IN_REG_SET (initial, 0, reg_num,
> +     {
>         /* If it's of significant degree, place it on the spill_worklist.  */
>         if (ra_reg_info[reg_num]->degree >= reg_freedom (reg_num))
>   	{
> ! 	  debug_msg (2, "Inserting %d onto spill_worklist\n", reg_num);
>   	  SET_REGNO_REG_SET (spill_worklist, reg_num);
>   	}
>         /* If it's move related, put it on the freeze worklist.  */
>         else if (move_related (reg_num))
>   	{
> ! 	  debug_msg (2, "Inserting %d onto freeze_worklist\n", reg_num);
>   	  SET_REGNO_REG_SET (freeze_worklist, reg_num);
>   	}
>         /* Otherwise, put it on the simplify worklist.  */
>         else
>   	{
> ! 	  debug_msg (2, "Inserting %d onto simplify_worklist\n", reg_num);
>   	  SET_REGNO_REG_SET (simplify_worklist, reg_num);
>   	}
>       });
> +
> +   CLEAR_REG_SET (initial);
>   }
>
>   /* Returns 1 if the varray contains the register reg_num.  */
>
>
>