From c1ae3ca5d8842831d35b08e6e9ae1f983b39bc6b Mon Sep 17 00:00:00 2001
From: Richard Guenther <rguenther@suse.de>
Date: Fri, 10 Jun 2011 11:38:14 +0000
Subject: [PATCH] tree-ssa-forwprop.c (ssa_forward_propagate_and_combine): Scan
stmts forward when combining, visit inserted stmts when a stmt was changed.
2011-06-10 Richard Guenther <rguenther@suse.de>
* tree-ssa-forwprop.c (ssa_forward_propagate_and_combine):
Scan stmts forward when combining, visit inserted stmts when
a stmt was changed.
From-SVN: r174900
---
gcc/ChangeLog | 6 ++++++
gcc/tree-ssa-forwprop.c | 27 ++++++++++++++++++++++-----
2 files changed, 28 insertions(+), 5 deletions(-)
diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index fa56bf092b5a..ec2d7e9f0e26 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2011-06-10 Richard Guenther <rguenther@suse.de>
+
+ * tree-ssa-forwprop.c (ssa_forward_propagate_and_combine):
+ Scan stmts forward when combining, visit inserted stmts when
+ a stmt was changed.
+
2011-06-10 Paolo Carlini <paolo.carlini@oracle.com>
* tree.h (error_operand_p): Add.
diff --git a/gcc/tree-ssa-forwprop.c b/gcc/tree-ssa-forwprop.c
index 56ba5226af40..77a6264d560b 100644
--- a/gcc/tree-ssa-forwprop.c
+++ b/gcc/tree-ssa-forwprop.c
@@ -2212,7 +2212,8 @@ ssa_forward_propagate_and_combine (void)
FOR_EACH_BB (bb)
{
- gimple_stmt_iterator gsi;
+ gimple_stmt_iterator gsi, prev;
+ bool prev_initialized;
/* Apply forward propagation to all stmts in the basic-block.
Note we update GSI within the loop as necessary. */
@@ -2304,7 +2305,8 @@ ssa_forward_propagate_and_combine (void)
/* Combine stmts with the stmts defining their operands.
Note we update GSI within the loop as necessary. */
- for (gsi = gsi_last_bb (bb); !gsi_end_p (gsi);)
+ prev_initialized = false;
+ for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi);)
{
gimple stmt = gsi_stmt (gsi);
bool changed = false;
@@ -2386,9 +2388,24 @@ ssa_forward_propagate_and_combine (void)
default:;
}
- /* If the stmt changed try combining it again. */
- if (!changed)
- gsi_prev (&gsi);
+ if (changed)
+ {
+ /* If the stmt changed then re-visit it and the statements
+ inserted before it. */
+ if (!prev_initialized)
+ gsi = gsi_start_bb (bb);
+ else
+ {
+ gsi = prev;
+ gsi_next (&gsi);
+ }
+ }
+ else
+ {
+ prev = gsi;
+ prev_initialized = true;
+ gsi_next (&gsi);
+ }
}
}
--
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