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PR tree-optimization/57337
- From: Easwaran Raman <eraman at google dot com>
- To: gcc-patches at gcc dot gnu dot org
- Cc: Richard Biener <richard dot guenther at gmail dot com>
- Date: Thu, 23 May 2013 10:26:43 -0700
- Subject: PR tree-optimization/57337
This addresses the case where UID alone is not sufficient to figure
out which statement appears earlier in a BB. Bootstraps and no test
regressions in x86_64 on linux. Ok for trunk?
Thanks,
Easwaran
2013-05-23 Easwaran Raman <eraman@google.com>
PR tree-optimization/57337
* tree-ssa-reassoc.c (appears_later_in_bb): New function.
(find_insert_point): Correctly identify the insertion point
when two statements with the same UID is compared.
Index: gcc/tree-ssa-reassoc.c
===================================================================
--- gcc/tree-ssa-reassoc.c (revision 199211)
+++ gcc/tree-ssa-reassoc.c (working copy)
@@ -2866,6 +2866,31 @@ not_dominated_by (gimple a, gimple b)
}
+/* Among STMT1 and STMT2, return the statement that appears later. Both
+ statements are in same BB and have the same UID. */
+
+static gimple
+appears_later_in_bb (gimple stmt1, gimple stmt2)
+{
+ unsigned uid = gimple_uid (stmt1);
+ gimple_stmt_iterator gsi = gsi_for_stmt (stmt1);
+ gsi_next (&gsi);
+ if (gsi_end_p (gsi))
+ return stmt1;
+ for (; !gsi_end_p (gsi); gsi_next (&gsi))
+ {
+ gimple stmt = gsi_stmt (gsi);
+
+ /* If STMT has a different UID than STMT1 and we haven't seen
+ STMT2 during traversal, we know STMT1 appears later. */
+ if (gimple_uid (stmt) != uid)
+ return stmt1;
+ else if (stmt == stmt2)
+ return stmt2;
+ }
+ gcc_unreachable ();
+}
+
/* Find the statement after which STMT must be moved so that the
dependency from DEP_STMT to STMT is maintained. */
@@ -2875,7 +2900,11 @@ find_insert_point (gimple stmt, gimple dep_stmt)
gimple insert_stmt = stmt;
if (dep_stmt == NULL)
return stmt;
- if (not_dominated_by (insert_stmt, dep_stmt))
+ if (gimple_uid (insert_stmt) == gimple_uid (dep_stmt)
+ && gimple_bb (insert_stmt) == gimple_bb (dep_stmt)
+ && insert_stmt != dep_stmt)
+ insert_stmt = appears_later_in_bb (insert_stmt, dep_stmt);
+ else if (not_dominated_by (insert_stmt, dep_stmt))
insert_stmt = dep_stmt;
return insert_stmt;
}