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Re: RFA: PATCH to make fold_indirect_ref_1 fold more things
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)?
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;
+ }
}
}