From e639b20676a9eab048bfdcf007b7ab3b6398a845 Mon Sep 17 00:00:00 2001
From: Sebastian Pop <sebastian.pop@amd.com>
Date: Wed, 10 Nov 2010 16:06:47 +0000
Subject: [PATCH] Fix PR45971: do not predicate condition phi nodes that are
 scev analyzable.

2010-11-10  Sebastian Pop  <sebastian.pop@amd.com>

	PR tree-optimization/45971
	* tree-if-conv.c (predicate_scalar_phi): Do not generate a COND_EXPR
	for phi nodes analyzable by scev.

	* gcc.dg/vect/O3-pr45971.c: New.

From-SVN: r166544
---
 gcc/ChangeLog                          |  6 ++++++
 gcc/testsuite/ChangeLog                |  5 +++++
 gcc/testsuite/gcc.dg/vect/O3-pr45971.c | 13 +++++++++++++
 gcc/tree-if-conv.c                     | 10 +++++++---
 4 files changed, 31 insertions(+), 3 deletions(-)
 create mode 100644 gcc/testsuite/gcc.dg/vect/O3-pr45971.c

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index e0f89586ba9..09dd6ccd0c9 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2010-11-10  Sebastian Pop  <sebastian.pop@amd.com>
+
+	PR tree-optimization/45971
+	* tree-if-conv.c (predicate_scalar_phi): Do not generate a COND_EXPR
+	for phi nodes analyzable by scev.
+
 2010-11-10  Richard Guenther  <rguenther@suse.de>
 
 	PR tree-optimization/44964
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 92a850909a5..e8fe4c48c13 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2010-11-10  Sebastian Pop  <sebastian.pop@amd.com>
+
+	PR tree-optimization/45971
+	* gcc.dg/vect/O3-pr45971.c: New.
+
 2010-11-10  Richard Guenther  <rguenther@suse.de>
 
 	PR tree-optimization/44964
diff --git a/gcc/testsuite/gcc.dg/vect/O3-pr45971.c b/gcc/testsuite/gcc.dg/vect/O3-pr45971.c
new file mode 100644
index 00000000000..1b7c65c8066
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vect/O3-pr45971.c
@@ -0,0 +1,13 @@
+/* { dg-do compile } */
+/* { dg-require-effective-target vect_int } */
+
+void
+foo (int *x, int *y)
+{
+  int i;
+  for (i = 0; i < 11; i++)
+    y[i] = (x[i] == 1) ? i + 1 : -(i + 1);
+}
+
+/* { dg-final { cleanup-tree-dump "vect" } } */
+
diff --git a/gcc/tree-if-conv.c b/gcc/tree-if-conv.c
index 17b66721e5d..fc6584584c1 100644
--- a/gcc/tree-if-conv.c
+++ b/gcc/tree-if-conv.c
@@ -1224,7 +1224,7 @@ predicate_scalar_phi (gimple phi, tree cond,
 {
   gimple new_stmt;
   basic_block bb;
-  tree rhs, res, arg;
+  tree rhs, res, arg, scev;
 
   gcc_assert (gimple_code (phi) == GIMPLE_PHI
 	      && gimple_phi_num_args (phi) == 2);
@@ -1236,8 +1236,12 @@ predicate_scalar_phi (gimple phi, tree cond,
 
   bb = gimple_bb (phi);
 
-  arg = degenerate_phi_result (phi);
-  if (arg)
+  if ((arg = degenerate_phi_result (phi))
+      || ((scev = analyze_scalar_evolution (gimple_bb (phi)->loop_father,
+					    res))
+	  && !chrec_contains_undetermined (scev)
+	  && scev != res
+	  && (arg = gimple_phi_arg_def (phi, 0))))
     rhs = arg;
   else
     {