RFC: PATCH: Remove 26 element limit in vector

[Richard Guenther]

On Wed, Mar 30, 2011 at 8:09 PM, H.J. Lu <hongjiu.lu@intel.com> wrote:
> On Wed, Mar 30, 2011 at 08:02:38AM -0700, H.J. Lu wrote:
>> Hi,
>>
>> Currently, we limit XVECEXP to 26 elements in machine description
>> since we use letters 'a' to 'z' to encode them.  I don't see any
>> reason why we can't go beyond 'z'.  This patch removes this restriction.
>> Any comments?
>>
>
> That was wrong.  The problem is in vector elements.  This patch passes
> bootstrap.  Any comments?

Do you really need it?

Richard.

> Thanks.
>
>
> H.J.
> ---
> 2011-03-30  H.J. Lu  <hongjiu.lu@intel.com>
>
>        * genrecog.c (VECTOR_ELEMENT_BASE): New.
>        (add_to_sequence): Add assert.  Use VECTOR_ELEMENT_BASE to
>        encode vector elements.
>        (change_state): Check and support VECTOR_ELEMENT_BASE.
>        (make_insn_sequence): Add assert.
>
> diff --git a/gcc/genrecog.c b/gcc/genrecog.c
> index 74dd0a7..40e9c4d 100644
> --- a/gcc/genrecog.c
> +++ b/gcc/genrecog.c
> @@ -465,6 +465,9 @@ extern void debug_decision
>   (struct decision *);
>  extern void debug_decision_list
>   (struct decision *);
> +
> +/* The base of vector element.  */
> +#define VECTOR_ELEMENT_BASE 0x80
>
>  /* Create a new node in sequence after LAST.  */
>
> @@ -912,6 +915,7 @@ add_to_sequence (rtx pattern, struct decision_head *last, const char *position,
>              /* Which insn we're looking at is represented by A-Z. We don't
>                 ever use 'A', however; it is always implied.  */
>
> +             gcc_assert (i < 26);
>              subpos[depth] = (i > 0 ? 'A' + i : 0);
>              sub = add_to_sequence (XVECEXP (pattern, 0, i),
>                                     last, subpos, insn_type, 0);
> @@ -1002,6 +1006,9 @@ add_to_sequence (rtx pattern, struct decision_head *last, const char *position,
>            char base = (was_code == MATCH_OPERATOR ? '0' : 'a');
>            for (i = 0; i < (size_t) XVECLEN (pattern, 2); i++)
>              {
> +               gcc_assert (was_code == MATCH_OPERATOR
> +                           ? ISDIGIT (i + base)
> +                           : ISLOWER (i + base));
>                subpos[depth] = i + base;
>                sub = add_to_sequence (XVECEXP (pattern, 2, i),
>                                       &sub->success, subpos, insn_type, 0);
> @@ -1102,7 +1109,9 @@ add_to_sequence (rtx pattern, struct decision_head *last, const char *position,
>            int j;
>            for (j = 0; j < XVECLEN (pattern, i); j++)
>              {
> -               subpos[depth] = 'a' + j;
> +               int val = j + VECTOR_ELEMENT_BASE;
> +               gcc_assert (val <= UCHAR_MAX);
> +               subpos[depth] = val;
>                sub = add_to_sequence (XVECEXP (pattern, i, j),
>                                       &sub->success, subpos, insn_type, 0);
>              }
> @@ -1779,6 +1788,10 @@ change_state (const char *oldpos, const char *newpos, const char *indent)
>       else if (ISLOWER (newpos[depth]))
>        printf ("%sx%d = XVECEXP (x%d, 0, %d);\n",
>                indent, depth + 1, depth, newpos[depth] - 'a');
> +      else if (((unsigned char) newpos[depth]) >= VECTOR_ELEMENT_BASE)
> +       printf ("%sx%d = XVECEXP (x%d, 0, %d);\n",
> +               indent, depth + 1, depth,
> +               ((unsigned char) newpos[depth]) - VECTOR_ELEMENT_BASE);
>       else
>        printf ("%sx%d = XEXP (x%d, %c);\n",
>                indent, depth + 1, depth, newpos[depth]);
> @@ -2528,6 +2541,7 @@ make_insn_sequence (rtx insn, enum routine_type type)
>        }
>       XVECLEN (x, 0) = j;
>
> +      gcc_assert ((j - 1) < 26);
>       c_test_pos[0] = 'A' + j - 1;
>       c_test_pos[1] = '\0';
>     }
>