MEM = "abcd" expansion improvements

Hi!

This patch slightly cleans up MEM = STRING_CST and MEM = MEM_REF<&STRING_CST, 0>
expansion by sharing the code for STRING_CST and MEM_REF<&STRING_CST, 0>
and allows it even for non-BLKmode mode - e.g. for "abcd" the mode
is SImode, but as long as target is MEM it is desirable to optimize it
using store_by_pieces.

Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?

2010-10-11  Jakub Jelinek  <jakub@redhat.com>

	* expr.c (store_expr): Share code for STRING_CST and
	MEM_REF of &STRING_CST cases.  Don't require BLKmode, instead
	check if target is a MEM.


	Jakub

On Mon, Oct 11, 2010 at 10:41 PM, Jakub Jelinek <jakub@redhat.com> wrote:
> Hi!
>
> This patch slightly cleans up MEM = STRING_CST and MEM = MEM_REF<&STRING_CST, 0>
> expansion by sharing the code for STRING_CST and MEM_REF<&STRING_CST, 0>
> and allows it even for non-BLKmode mode - e.g. for "abcd" the mode
> is SImode, but as long as target is MEM it is desirable to optimize it
> using store_by_pieces.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?

Ok.

Thanks,
Richard.

> 2010-10-11  Jakub Jelinek  <jakub@redhat.com>
>
>        * expr.c (store_expr): Share code for STRING_CST and
>        MEM_REF of &STRING_CST cases.  Don't require BLKmode, instead
>        check if target is a MEM.
>
> --- gcc/expr.c.jj       2010-10-11 07:51:09.000000000 +0200
> +++ gcc/expr.c  2010-10-11 13:46:05.000000000 +0200
> @@ -4636,62 +4636,26 @@ store_expr (tree exp, rtx target, int ca
>
>       return NULL_RTX;
>     }
> -  else if (TREE_CODE (exp) == STRING_CST
> +  else if ((TREE_CODE (exp) == STRING_CST
> +           || (TREE_CODE (exp) == MEM_REF
> +               && TREE_CODE (TREE_OPERAND (exp, 0)) == ADDR_EXPR
> +               && TREE_CODE (TREE_OPERAND (TREE_OPERAND (exp, 0), 0))
> +                  == STRING_CST
> +               && integer_zerop (TREE_OPERAND (exp, 1))))
>           && !nontemporal && !call_param_p
> -          && TREE_STRING_LENGTH (exp) > 0
> -          && TYPE_MODE (TREE_TYPE (exp)) == BLKmode)
> +          && MEM_P (target))
>     {
>       /* Optimize initialization of an array with a STRING_CST.  */
>       HOST_WIDE_INT exp_len, str_copy_len;
>       rtx dest_mem;
> +      tree str = TREE_CODE (exp) == STRING_CST
> +                ? exp : TREE_OPERAND (TREE_OPERAND (exp, 0), 0);
>
>       exp_len = int_expr_size (exp);
>       if (exp_len <= 0)
>        goto normal_expr;
>
> -      str_copy_len = strlen (TREE_STRING_POINTER (exp));
> -      if (str_copy_len < TREE_STRING_LENGTH (exp) - 1)
> -       goto normal_expr;
> -
> -      str_copy_len = TREE_STRING_LENGTH (exp);
> -      if ((STORE_MAX_PIECES & (STORE_MAX_PIECES - 1)) == 0)
> -       {
> -         str_copy_len += STORE_MAX_PIECES - 1;
> -         str_copy_len &= ~(STORE_MAX_PIECES - 1);
> -       }
> -      str_copy_len = MIN (str_copy_len, exp_len);
> -      if (!can_store_by_pieces (str_copy_len, builtin_strncpy_read_str,
> -                               CONST_CAST(char *, TREE_STRING_POINTER (exp)),
> -                               MEM_ALIGN (target), false))
> -       goto normal_expr;
> -
> -      dest_mem = target;
> -
> -      dest_mem = store_by_pieces (dest_mem,
> -                                 str_copy_len, builtin_strncpy_read_str,
> -                                 CONST_CAST(char *, TREE_STRING_POINTER (exp)),
> -                                 MEM_ALIGN (target), false,
> -                                 exp_len > str_copy_len ? 1 : 0);
> -      if (exp_len > str_copy_len)
> -       clear_storage (adjust_address (dest_mem, BLKmode, 0),
> -                      GEN_INT (exp_len - str_copy_len),
> -                      BLOCK_OP_NORMAL);
> -      return NULL_RTX;
> -    }
> -  else if (TREE_CODE (exp) == MEM_REF
> -          && TREE_CODE (TREE_OPERAND (exp, 0)) == ADDR_EXPR
> -          && TREE_CODE (TREE_OPERAND (TREE_OPERAND (exp, 0), 0)) == STRING_CST
> -          && integer_zerop (TREE_OPERAND (exp, 1))
> -          && !nontemporal && !call_param_p
> -          && TYPE_MODE (TREE_TYPE (exp)) == BLKmode)
> -    {
> -      /* Optimize initialization of an array with a STRING_CST.  */
> -      HOST_WIDE_INT exp_len, str_copy_len;
> -      rtx dest_mem;
> -      tree str = TREE_OPERAND (TREE_OPERAND (exp, 0), 0);
> -
> -      exp_len = int_expr_size (exp);
> -      if (exp_len <= 0)
> +      if (TREE_STRING_LENGTH (str) <= 0)
>        goto normal_expr;
>
>       str_copy_len = strlen (TREE_STRING_POINTER (str));
> @@ -4699,14 +4663,15 @@ store_expr (tree exp, rtx target, int ca
>        goto normal_expr;
>
>       str_copy_len = TREE_STRING_LENGTH (str);
> -      if ((STORE_MAX_PIECES & (STORE_MAX_PIECES - 1)) == 0)
> +      if ((STORE_MAX_PIECES & (STORE_MAX_PIECES - 1)) == 0
> +         && TREE_STRING_POINTER (str)[TREE_STRING_LENGTH (str) - 1] == '\0')
>        {
>          str_copy_len += STORE_MAX_PIECES - 1;
>          str_copy_len &= ~(STORE_MAX_PIECES - 1);
>        }
>       str_copy_len = MIN (str_copy_len, exp_len);
>       if (!can_store_by_pieces (str_copy_len, builtin_strncpy_read_str,
> -                               CONST_CAST(char *, TREE_STRING_POINTER (str)),
> +                               CONST_CAST (char *, TREE_STRING_POINTER (str)),
>                                MEM_ALIGN (target), false))
>        goto normal_expr;
>
> @@ -4714,7 +4679,8 @@ store_expr (tree exp, rtx target, int ca
>
>       dest_mem = store_by_pieces (dest_mem,
>                                  str_copy_len, builtin_strncpy_read_str,
> -                                 CONST_CAST(char *, TREE_STRING_POINTER (str)),
> +                                 CONST_CAST (char *,
> +                                             TREE_STRING_POINTER (str)),
>                                  MEM_ALIGN (target), false,
>                                  exp_len > str_copy_len ? 1 : 0);
>       if (exp_len > str_copy_len)
>
>        Jakub
>