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re PR tree-optimization/22303 (CCP does not handle STRING_CSTs)

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2006-05-16  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/22303
	* tree-ssa-ccp.c (fold_const_aggregate_ref): Handle reads
	from STRING_CSTs.
	(evaluate_stmt): Fall back to fold_const_aggregate_ref, if
	ccp_fold did not simplify the statement.

	* gcc.dg/tree-ssa/ssa-ccp-13.c: New testcase.

From-SVN: r113826
This commit is contained in:
Richard Guenther 2006-05-16 15:34:12 +00:00 committed by Richard Biener
parent 14c7833ccd
commit faaf14368b
4 changed files with 46 additions and 4 deletions
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8
gcc/ChangeLog
View File

@ -1,3 +1,11 @@
2006-05-16 Richard Guenther <rguenther@suse.de>
PR tree-optimization/22303
* tree-ssa-ccp.c (fold_const_aggregate_ref): Handle reads
from STRING_CSTs.
(evaluate_stmt): Fall back to fold_const_aggregate_ref, if
ccp_fold did not simplify the statement.
2006-05-16 H.J. Lu <hongjiu.lu@intel.com>
PR driver/26885

5
gcc/testsuite/ChangeLog
View File

@ -1,3 +1,8 @@
2006-05-16 Richard Guenther <rguenther@suse.de>
PR tree-optimization/22303
* gcc.dg/tree-ssa/ssa-ccp-13.c: New testcase.
2006-05-16 Jakub Jelinek <jakub@redhat.com>
PR middle-end/27573

14
gcc/testsuite/gcc.dg/tree-ssa/ssa-ccp-13.c Normal file
View File

@ -0,0 +1,14 @@
/* { dg-do compile } */
/* { dg-options "-O2 -fdump-tree-optimized" } */
static const char f[3] = "?";
int foo()
{
int i = 0;
return f[i] != '?';
}
/* { dg-final { scan-tree-dump "return 0;" "optimized" } } */
/* { dg-final { cleanup-tree-dump "optimized" } } */

23
gcc/tree-ssa-ccp.c
View File

@ -1011,7 +1011,8 @@ fold_const_aggregate_ref (tree t)
}
if (ctor == NULL_TREE
|| TREE_CODE (ctor) != CONSTRUCTOR
|| (TREE_CODE (ctor) != CONSTRUCTOR
&& TREE_CODE (ctor) != STRING_CST)
|| !TREE_STATIC (ctor))
return NULL_TREE;
@ -1036,6 +1037,20 @@ fold_const_aggregate_ref (tree t)
return NULL_TREE;
}
/* Fold read from constant string. */
if (TREE_CODE (ctor) == STRING_CST)
{
if ((TYPE_MODE (TREE_TYPE (t))
== TYPE_MODE (TREE_TYPE (TREE_TYPE (ctor))))
&& (GET_MODE_CLASS (TYPE_MODE (TREE_TYPE (TREE_TYPE (ctor))))
== MODE_INT)
&& GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (TREE_TYPE (ctor)))) == 1
&& compare_tree_int (idx, TREE_STRING_LENGTH (ctor)) < 0)
return build_int_cst (TREE_TYPE (t), (TREE_STRING_POINTER (ctor)
[TREE_INT_CST_LOW (idx)]));
return NULL_TREE;
}
/* Whoo-hoo! I'll fold ya baby. Yeah! */
FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (ctor), cnt, cfield, cval)
if (tree_int_cst_equal (cfield, idx))
@ -1104,7 +1119,7 @@ static prop_value_t
evaluate_stmt (tree stmt)
{
prop_value_t val;
tree simplified;
tree simplified = NULL_TREE;
ccp_lattice_t likelyvalue = likely_value (stmt);
val.mem_ref = NULL_TREE;
@ -1115,14 +1130,14 @@ evaluate_stmt (tree stmt)
simplified = ccp_fold (stmt);
/* If the statement is likely to have a VARYING result, then do not
bother folding the statement. */
else if (likelyvalue == VARYING)
if (likelyvalue == VARYING)
simplified = get_rhs (stmt);
/* If the statement is an ARRAY_REF or COMPONENT_REF into constant
aggregates, extract the referenced constant. Otherwise the
statement is likely to have an UNDEFINED value, and there will be
nothing to do. Note that fold_const_aggregate_ref returns
NULL_TREE if the first case does not match. */
else
else if (!simplified)
simplified = fold_const_aggregate_ref (get_rhs (stmt));
if (simplified && is_gimple_min_invariant (simplified))