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Re: RFA: PATCH to make fold_indirect_ref_1 fold more things


On Sun, Oct 31, 2010 at 9:27 PM, Jason Merrill <jason@redhat.com> wrote:
> On 10/29/2010 07:32 PM, Richard Guenther wrote:
>>>
>>> I guess I can just do this folding in the constexpr expander...
>>
>> Yeah, I think that should be safer.
>
> OK, how about this patch that only adds folding INDIRECT_REF of
> POINTER_PLUS_EXPR to ARRAY_REF (and combines the two POINTER_PLUS_EXPR
> hunks)?

That works for me.

Thanks,
Richard.

> commit 49fd7e2c159bc5de19055c64c19e26778167cc28
> Author: Jason Merrill <jason@redhat.com>
> Date: ? Tue Oct 26 14:49:37 2010 -0400
>
> ? ? ? ?* fold-const.c (fold_indirect_ref_1): Handle folding
> ? ? ? ?POINTER_PLUS_EXPR to ARRAY_REF.
>
> diff --git a/gcc/fold-const.c b/gcc/fold-const.c
> index decb0fb..dd69a20 100644
> --- a/gcc/fold-const.c
> +++ b/gcc/fold-const.c
> @@ -15649,53 +15649,59 @@ fold_indirect_ref_1 (location_t loc, tree type,
> tree op0)
> ? ? ? ?}
> ? ? }
>
> - ?/* ((foo*)&vectorfoo)[1] => BIT_FIELD_REF<vectorfoo,...> */
> ? if (TREE_CODE (sub) == POINTER_PLUS_EXPR
> ? ? ? && TREE_CODE (TREE_OPERAND (sub, 1)) == INTEGER_CST)
> ? ? {
> ? ? ? tree op00 = TREE_OPERAND (sub, 0);
> ? ? ? tree op01 = TREE_OPERAND (sub, 1);
> - ? ? ?tree op00type;
>
> ? ? ? STRIP_NOPS (op00);
> - ? ? ?op00type = TREE_TYPE (op00);
> - ? ? ?if (TREE_CODE (op00) == ADDR_EXPR
> - ? ? ? ? ?&& TREE_CODE (TREE_TYPE (op00type)) == VECTOR_TYPE
> - ? ? ? ? ?&& type == TREE_TYPE (TREE_TYPE (op00type)))
> + ? ? ?if (TREE_CODE (op00) == ADDR_EXPR)
> ? ? ? ?{
> - ? ? ? ? HOST_WIDE_INT offset = tree_low_cst (op01, 0);
> - ? ? ? ? tree part_width = TYPE_SIZE (type);
> - ? ? ? ? unsigned HOST_WIDE_INT part_widthi = tree_low_cst (part_width,
> 0)/BITS_PER_UNIT;
> - ? ? ? ? unsigned HOST_WIDE_INT indexi = offset * BITS_PER_UNIT;
> - ? ? ? ? tree index = bitsize_int (indexi);
> + ? ? ? ? tree op00type;
> + ? ? ? ? op00 = TREE_OPERAND (op00, 0);
> + ? ? ? ? op00type = TREE_TYPE (op00);
>
> - ? ? ? ? if (offset/part_widthi <= TYPE_VECTOR_SUBPARTS (TREE_TYPE
> (op00type)))
> - ? ? ? ? ? return fold_build3_loc (loc,
> - ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? BIT_FIELD_REF, type, TREE_OPERAND (op00, 0),
> - ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? part_width, index);
> + ? ? ? ? /* ((foo*)&vectorfoo)[1] => BIT_FIELD_REF<vectorfoo,...> */
> + ? ? ? ? if (TREE_CODE (op00type) == VECTOR_TYPE
> + ? ? ? ? ? ? && type == TREE_TYPE (op00type))
> + ? ? ? ? ? {
> + ? ? ? ? ? ? HOST_WIDE_INT offset = tree_low_cst (op01, 0);
> + ? ? ? ? ? ? tree part_width = TYPE_SIZE (type);
> + ? ? ? ? ? ? unsigned HOST_WIDE_INT part_widthi = tree_low_cst (part_width,
> 0)/BITS_PER_UNIT;
> + ? ? ? ? ? ? unsigned HOST_WIDE_INT indexi = offset * BITS_PER_UNIT;
> + ? ? ? ? ? ? tree index = bitsize_int (indexi);
>
> - ? ? ? }
> - ? ?}
> + ? ? ? ? ? ? if (offset/part_widthi <= TYPE_VECTOR_SUBPARTS (op00type))
> + ? ? ? ? ? ? ? return fold_build3_loc (loc,
> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? BIT_FIELD_REF, type, op00,
> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? part_width, index);
>
> -
> - ?/* ((foo*)&complexfoo)[1] => __imag__ complexfoo */
> - ?if (TREE_CODE (sub) == POINTER_PLUS_EXPR
> - ? ? ?&& TREE_CODE (TREE_OPERAND (sub, 1)) == INTEGER_CST)
> - ? ?{
> - ? ? ?tree op00 = TREE_OPERAND (sub, 0);
> - ? ? ?tree op01 = TREE_OPERAND (sub, 1);
> - ? ? ?tree op00type;
> -
> - ? ? ?STRIP_NOPS (op00);
> - ? ? ?op00type = TREE_TYPE (op00);
> - ? ? ?if (TREE_CODE (op00) == ADDR_EXPR
> - ? ? ? ? && TREE_CODE (TREE_TYPE (op00type)) == COMPLEX_TYPE
> - ? ? ? ? && type == TREE_TYPE (TREE_TYPE (op00type)))
> - ? ? ? {
> - ? ? ? ? tree size = TYPE_SIZE_UNIT (type);
> - ? ? ? ? if (tree_int_cst_equal (size, op01))
> - ? ? ? ? ? return fold_build1_loc (loc, IMAGPART_EXPR, type,
> - ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? TREE_OPERAND (op00, 0));
> + ? ? ? ? ? }
> + ? ? ? ? /* ((foo*)&complexfoo)[1] => __imag__ complexfoo */
> + ? ? ? ? else if (TREE_CODE (op00type) == COMPLEX_TYPE
> + ? ? ? ? ? ? ? ? ?&& type == TREE_TYPE (op00type))
> + ? ? ? ? ? {
> + ? ? ? ? ? ? tree size = TYPE_SIZE_UNIT (type);
> + ? ? ? ? ? ? if (tree_int_cst_equal (size, op01))
> + ? ? ? ? ? ? ? return fold_build1_loc (loc, IMAGPART_EXPR, type, op00);
> + ? ? ? ? ? }
> + ? ? ? ? /* ((foo *)&fooarray)[1] => fooarray[1] */
> + ? ? ? ? else if (TREE_CODE (op00type) == ARRAY_TYPE
> + ? ? ? ? ? ? ? ? ?&& type == TREE_TYPE (op00type))
> + ? ? ? ? ? {
> + ? ? ? ? ? ? tree type_domain = TYPE_DOMAIN (op00type);
> + ? ? ? ? ? ? tree min_val = size_zero_node;
> + ? ? ? ? ? ? if (type_domain && TYPE_MIN_VALUE (type_domain))
> + ? ? ? ? ? ? ? min_val = TYPE_MIN_VALUE (type_domain);
> + ? ? ? ? ? ? op01 = size_binop_loc (loc, EXACT_DIV_EXPR, op01,
> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?TYPE_SIZE_UNIT (type));
> + ? ? ? ? ? ? op01 = size_binop_loc (loc, PLUS_EXPR, op01, min_val);
> + ? ? ? ? ? ? op0 = build4 (ARRAY_REF, type, op00, op01,
> + ? ? ? ? ? ? ? ? ? ? ? ? ? NULL_TREE, NULL_TREE);
> + ? ? ? ? ? ? SET_EXPR_LOCATION (op0, loc);
> + ? ? ? ? ? ? return op0;
> + ? ? ? ? ? }
> ? ? ? ?}
> ? ? }
>
>
>


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