[PATCH] Fix PR46924: Do not detect reductions outside the current SESE region.

[Sebastian Pop]

Hi,

Without this patch we ended up analyzing scalar reductions outside the
currently analyzed scop.  I am testing this on amd64-linux.  I will
commit this to trunk after regstrap.

Sebastian

2010-12-16  Sebastian Pop  <sebastian.pop@amd.com>

	PR tree-optimization/46924
	* graphite-sese-to-poly.c (detect_commutative_reduction): Do not
	detect reductions outside the current SESE region.
	* sese.h (stmt_in_sese_p): New.
	(defined_in_sese_p): Call stmt_in_sese_p.

	* gcc.dg/graphite/pr46924.c: New.
---
 gcc/ChangeLog                           |    8 ++++++++
 gcc/graphite-sese-to-poly.c             |   15 +++++++++------
 gcc/sese.h                              |   13 ++++++++++---
 gcc/testsuite/ChangeLog                 |    5 +++++
 gcc/testsuite/gcc.dg/graphite/pr46924.c |   18 ++++++++++++++++++
 5 files changed, 50 insertions(+), 9 deletions(-)
 create mode 100644 gcc/testsuite/gcc.dg/graphite/pr46924.c

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 287d21e..2fe57ab 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,13 @@
 2010-12-16  Sebastian Pop  <sebastian.pop@amd.com>
 
+	PR tree-optimization/46924
+	* graphite-sese-to-poly.c (detect_commutative_reduction): Do not
+	detect reductions outside the current SESE region.
+	* sese.h (stmt_in_sese_p): New.
+	(defined_in_sese_p): Call stmt_in_sese_p.
+
+2010-12-16  Sebastian Pop  <sebastian.pop@amd.com>
+
 	PR tree-optimization/46404
 	* graphite-clast-to-gimple.c (gloog): Call scev_reset.
 
diff --git a/gcc/graphite-sese-to-poly.c b/gcc/graphite-sese-to-poly.c
index 5036fba..2eadd25 100644
--- a/gcc/graphite-sese-to-poly.c
+++ b/gcc/graphite-sese-to-poly.c
@@ -2857,12 +2857,12 @@ initial_value_for_loop_phi (gimple phi)
   return NULL_TREE;
 }
 
-/* Detect commutative and associative scalar reductions starting at
-   the loop closed phi node STMT.  Return the phi node of the
-   reduction cycle, or NULL.  */
+/* Detect commutative and associative scalar reductions belonging to
+   the SCOP starting at the loop closed phi node STMT.  Return the phi
+   node of the reduction cycle, or NULL.  */
 
 static gimple
-detect_commutative_reduction (gimple stmt, VEC (gimple, heap) **in,
+detect_commutative_reduction (scop_p scop, gimple stmt, VEC (gimple, heap) **in,
 			      VEC (gimple, heap) **out)
 {
   if (scalar_close_phi_node_p (stmt))
@@ -2879,7 +2879,10 @@ detect_commutative_reduction (gimple stmt, VEC (gimple, heap) **in,
       gcc_assert (gimple_phi_num_args (stmt) == 1);
 
       def = SSA_NAME_DEF_STMT (arg);
-      loop_phi = detect_commutative_reduction (def, in, out);
+      if (!stmt_in_sese_p (def, SCOP_REGION (scop)))
+	return NULL;
+
+      loop_phi = detect_commutative_reduction (scop, def, in, out);
 
       if (loop_phi)
 	{
@@ -3018,7 +3021,7 @@ rewrite_commutative_reductions_out_of_ssa_close_phi (scop_p scop,
   VEC (gimple, heap) *in = VEC_alloc (gimple, heap, 10);
   VEC (gimple, heap) *out = VEC_alloc (gimple, heap, 10);
 
-  detect_commutative_reduction (close_phi, &in, &out);
+  detect_commutative_reduction (scop, close_phi, &in, &out);
   res = VEC_length (gimple, in) > 0;
   if (res)
     translate_scalar_reduction_to_array (scop, in, out);
diff --git a/gcc/sese.h b/gcc/sese.h
index 10bf874..97807d8 100644
--- a/gcc/sese.h
+++ b/gcc/sese.h
@@ -114,15 +114,22 @@ bb_in_sese_p (basic_block bb, sese region)
   return bb_in_region (bb, entry, exit);
 }
 
+/* Returns true when STMT is defined in REGION.  */
+
+static inline bool
+stmt_in_sese_p (gimple stmt, sese region)
+{
+  basic_block bb = gimple_bb (stmt);
+  return bb && bb_in_sese_p (bb, region);
+}
+
 /* Returns true when NAME is defined in REGION.  */
 
 static inline bool
 defined_in_sese_p (tree name, sese region)
 {
   gimple stmt = SSA_NAME_DEF_STMT (name);
-  basic_block bb = gimple_bb (stmt);
-
-  return bb && bb_in_sese_p (bb, region);
+  return stmt_in_sese_p (stmt, region);
 }
 
 /* Returns true when LOOP is in REGION.  */
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 8cfb516..b44f38f 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,5 +1,10 @@
 2010-12-16  Sebastian Pop  <sebastian.pop@amd.com>
 
+	PR tree-optimization/46924
+	* gcc.dg/graphite/pr46924.c: New.
+
+2010-12-16  Sebastian Pop  <sebastian.pop@amd.com>
+
 	PR tree-optimization/46404
 	* gcc.dg/graphite/pr46404-1.c: New.
 
diff --git a/gcc/testsuite/gcc.dg/graphite/pr46924.c b/gcc/testsuite/gcc.dg/graphite/pr46924.c
new file mode 100644
index 0000000..5788c2c
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/graphite/pr46924.c
@@ -0,0 +1,18 @@
+/* { dg-options "-O -fgraphite-identity -ffast-math -fno-tree-loop-im" } */
+
+struct S
+{
+  int n;
+  float *a;
+};
+
+float foo (struct S *s)
+{
+  float f = 0, g=0;
+  int i;
+  for (i = 0; i < s->n; i++)
+    f += s->a[i];
+  for (i = 0; i < s->n; i++)
+    ;
+  return f;
+}
-- 
1.7.1