From faaf14368b72d741b4ea5bcb6b8cb172fb847c43 Mon Sep 17 00:00:00 2001
From: Richard Guenther <rguenther@suse.de>
Date: Tue, 16 May 2006 15:34:12 +0000
Subject: [PATCH] re PR tree-optimization/22303 (CCP does not handle
STRING_CSTs)
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
---
gcc/ChangeLog | 8 ++++++++
gcc/testsuite/ChangeLog | 5 +++++
gcc/testsuite/gcc.dg/tree-ssa/ssa-ccp-13.c | 14 +++++++++++++
gcc/tree-ssa-ccp.c | 23 ++++++++++++++++++----
4 files changed, 46 insertions(+), 4 deletions(-)
create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/ssa-ccp-13.c
diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index e5a58791f5ed..c7bfa59c0ec4 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -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
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 8e94d149213a..ec6b784ffd11 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -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
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/ssa-ccp-13.c b/gcc/testsuite/gcc.dg/tree-ssa/ssa-ccp-13.c
new file mode 100644
index 000000000000..d35adee514d6
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/ssa-ccp-13.c
@@ -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" } } */
+
diff --git a/gcc/tree-ssa-ccp.c b/gcc/tree-ssa-ccp.c
index 83dce72770b1..53050e68429a 100644
--- a/gcc/tree-ssa-ccp.c
+++ b/gcc/tree-ssa-ccp.c
@@ -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))
--
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