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expr.c (expand_expr_real_1, [...]): Properly fold with non-zero lower bound.

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* expr.c (expand_expr_real_1, case ARRAY_REF): Properly fold with
	non-zero lower bound.

From-SVN: r91446
This commit is contained in:
Richard Kenner 2004-11-29 00:52:33 +00:00 committed by Richard Kenner
parent 97f8d136d1
commit 45d8710e5e
2 changed files with 9 additions and 24 deletions
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gcc/ChangeLog
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@ -1,5 +1,8 @@
2004-11-28 Richard Kenner <kenner@vlsi1.ultra.nyu.edu>
* expr.c (expand_expr_real_1, case ARRAY_REF): Properly fold with
non-zero lower bound.
* expr.c (categorize_ctor_elements_1, case STRING_CST): New case.
2004-11-28 Matt Kraai <kraai@alumni.cmu.edu>

30
gcc/expr.c
View File

@ -6744,22 +6744,7 @@ expand_expr_real_1 (tree exp, rtx target, enum machine_mode tmode,
{
tree array = TREE_OPERAND (exp, 0);
tree low_bound = array_ref_low_bound (exp);
tree index = convert (sizetype, TREE_OPERAND (exp, 1));
HOST_WIDE_INT i;
gcc_assert (TREE_CODE (TREE_TYPE (array)) == ARRAY_TYPE);
/* Optimize the special-case of a zero lower bound.
We convert the low_bound to sizetype to avoid some problems
with constant folding. (E.g. suppose the lower bound is 1,
and its mode is QI. Without the conversion, (ARRAY
+(INDEX-(unsigned char)1)) becomes ((ARRAY+(-(unsigned char)1))
+INDEX), which becomes (ARRAY+255+INDEX). Oops!) */
if (! integer_zerop (low_bound))
index = size_diffop (index, convert (sizetype, low_bound));
tree index = TREE_OPERAND (exp, 1);
/* Fold an expression like: "foo"[2].
This is not done in fold so it won't happen inside &.
@ -6786,19 +6771,16 @@ expand_expr_real_1 (tree exp, rtx target, enum machine_mode tmode,
&& modifier != EXPAND_MEMORY
&& TREE_CODE (array) == CONSTRUCTOR
&& ! TREE_SIDE_EFFECTS (array)
&& TREE_CODE (index) == INTEGER_CST
&& 0 > compare_tree_int (index,
list_length (CONSTRUCTOR_ELTS
(TREE_OPERAND (exp, 0)))))
&& TREE_CODE (index) == INTEGER_CST)
{
tree elem;
for (elem = CONSTRUCTOR_ELTS (TREE_OPERAND (exp, 0)),
i = TREE_INT_CST_LOW (index);
elem != 0 && i != 0; i--, elem = TREE_CHAIN (elem))
for (elem = CONSTRUCTOR_ELTS (array);
(elem && !tree_int_cst_equal (TREE_PURPOSE (elem), index));
elem = TREE_CHAIN (elem))
;
if (elem)
if (elem && !TREE_SIDE_EFFECTS (TREE_VALUE (elem)))
return expand_expr (fold (TREE_VALUE (elem)), target, tmode,
modifier);
}