This extends try_move_mult_to_index folding to be less picky about
the outermost array reference and handles a component-ref of an
array the same as if that were wrapped with an array-ref with
minimum index.
This consolidates array-ref reconstruction to the frontend-closest
position we have right now (eventually that function should move
to some c-family helper I guess).
Bootstrapped and tested on x86_64-unknown-linux-gnu, applied to trunk.
Richard.
2011-09-28 Richard Guenther <rguent...@suse.de>
PR middle-end/50460
* fold-const.c (try_move_mult_to_index): Handle &a.array the
same as &a.array[0].
Index: gcc/fold-const.c
===================================================================
*** gcc/fold-const.c (revision 179308)
--- gcc/fold-const.c (working copy)
*************** try_move_mult_to_index (location_t loc,
*** 6870,6875 ****
--- 6870,6929 ----
break;
}
+ else if (TREE_CODE (ref) == COMPONENT_REF
+ && TREE_CODE (TREE_TYPE (ref)) == ARRAY_TYPE)
+ {
+ tree domain;
+
+ /* Remember if this was a multi-dimensional array. */
+ if (TREE_CODE (TREE_OPERAND (ref, 0)) == ARRAY_REF)
+ mdim = true;
+
+ domain = TYPE_DOMAIN (TREE_TYPE (ref));
+ if (! domain)
+ continue;
+ itype = TREE_TYPE (domain);
+
+ step = TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (ref)));
+ if (TREE_CODE (step) != INTEGER_CST)
+ continue;
+
+ if (s)
+ {
+ if (! tree_int_cst_equal (step, s))
+ continue;
+ }
+ else
+ {
+ /* Try if delta is a multiple of step. */
+ tree tmp = div_if_zero_remainder (EXACT_DIV_EXPR, op1, step);
+ if (! tmp)
+ continue;
+ delta = tmp;
+ }
+
+ /* Only fold here if we can verify we do not overflow one
+ dimension of a multi-dimensional array. */
+ if (mdim)
+ {
+ tree tmp;
+
+ if (!TYPE_MIN_VALUE (domain)
+ || !TYPE_MAX_VALUE (domain)
+ || TREE_CODE (TYPE_MAX_VALUE (domain)) != INTEGER_CST)
+ continue;
+
+ tmp = fold_binary_loc (loc, PLUS_EXPR, itype,
+ fold_convert_loc (loc, itype,
+ TYPE_MIN_VALUE (domain)),
+ fold_convert_loc (loc, itype, delta));
+ if (TREE_CODE (tmp) != INTEGER_CST
+ || tree_int_cst_lt (TYPE_MAX_VALUE (domain), tmp))
+ continue;
+ }
+
+ break;
+ }
else
mdim = false;
*************** try_move_mult_to_index (location_t loc,
*** 6892,6903 ****
pos = TREE_OPERAND (pos, 0);
}
! TREE_OPERAND (pos, 1) = fold_build2_loc (loc, PLUS_EXPR, itype,
! fold_convert_loc (loc, itype,
! TREE_OPERAND (pos, 1)),
! fold_convert_loc (loc, itype, delta));
!
! return fold_build1_loc (loc, ADDR_EXPR, TREE_TYPE (addr), ret);
}
--- 6946,6974 ----
pos = TREE_OPERAND (pos, 0);
}
! if (TREE_CODE (ref) == ARRAY_REF)
! {
! TREE_OPERAND (pos, 1)
! = fold_build2_loc (loc, PLUS_EXPR, itype,
! fold_convert_loc (loc, itype, TREE_OPERAND (pos, 1)),
! fold_convert_loc (loc, itype, delta));
! return fold_build1_loc (loc, ADDR_EXPR, TREE_TYPE (addr), ret);
! }
! else if (TREE_CODE (ref) == COMPONENT_REF)
! {
! gcc_assert (ret == pos);
! ret = build4_loc (loc, ARRAY_REF, TREE_TYPE (TREE_TYPE (ref)), ret,
! fold_build2_loc
! (loc, PLUS_EXPR, itype,
! fold_convert_loc (loc, itype,
! TYPE_MIN_VALUE
! (TYPE_DOMAIN (TREE_TYPE (ref)))),
! fold_convert_loc (loc, itype, delta)),
! NULL_TREE, NULL_TREE);
! return build_fold_addr_expr_loc (loc, ret);
! }
! else
! gcc_unreachable ();
}
