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Re: Make get_value_for_expr check for INTEGER_CSTs


On Wed, Sep 18, 2019 at 8:54 AM Richard Sandiford
<richard.sandiford@arm.com> wrote:
>
> CONSTANT lattice values are symbolic constants rather than
> compile-time constants, so among other things can be POLY_INT_CSTs.
> This patch fixes a case in which we assumed all CONSTANTs were either
> ADDR_EXPRs or INTEGER_CSTs.
>
> This is tested by later SVE patches.
>
> Tested on aarch64-linux-gnu with SVE (with and without follow-on
> patches) and x86_64-linux-gnu.  OK to install?

OK.

Richard.

> Richard
>
>
> 2019-09-18  Richard Sandiford  <richard.sandiford@arm.com>
>
> gcc/
>         * tree-ssa-ccp.c (get_value_for_expr): Check whether CONSTANTs
>         are INTEGER_CSTs.
>
> Index: gcc/tree-ssa-ccp.c
> ===================================================================
> --- gcc/tree-ssa-ccp.c  2019-08-21 14:58:05.999057076 +0100
> +++ gcc/tree-ssa-ccp.c  2019-09-18 07:53:36.930481545 +0100
> @@ -615,9 +615,17 @@ get_value_for_expr (tree expr, bool for_
>           val.mask = -1;
>         }
>        if (for_bits_p
> -         && val.lattice_val == CONSTANT
> -         && TREE_CODE (val.value) == ADDR_EXPR)
> -       val = get_value_from_alignment (val.value);
> +         && val.lattice_val == CONSTANT)
> +       {
> +         if (TREE_CODE (val.value) == ADDR_EXPR)
> +           val = get_value_from_alignment (val.value);
> +         else if (TREE_CODE (val.value) != INTEGER_CST)
> +           {
> +             val.lattice_val = VARYING;
> +             val.value = NULL_TREE;
> +             val.mask = -1;
> +           }
> +       }
>        /* Fall back to a copy value.  */
>        if (!for_bits_p
>           && val.lattice_val == VARYING


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