call scev analysis in scop-detection as in sese-to-poly

Before our rewrite of the scop detection, we used to not have a valid SESE
region under hand, and so we used to do more ad-hoc analysis of data references
by trying to prove that at all levels of a loop nest the data references would
be still valid.

Now that we have a valid SESE region, we can call the scev analysis in the same
way on the same computed loop nest in the scop-detection as in the sese-to-poly.

Next step will be to cache the data references analyzed in the scop detection
and not compute the same info in sese-to-poly.

The patch fixes block-1.f90 that used to ICE on x86_64-linux when compiled with
-m32.  Patch passed bootstrap with BOOT_CFLAGS="-g -O2 -fgraphite-identity
-floop-nest-optimize" and check on x86_64-linux using ISL-0.15.

2015-09-28  Sebastian Pop  <s.pop@samsung.com>
	Aditya Kumar  <aditya.k7@samsung.com>

	PR tree-optimization/67754
	* graphite-scop-detection.c (stmt_has_simple_data_refs_p): Call
	scev analysis on the same loop nest as analyze_drs_in_stmts.
	* graphite-sese-to-poly.c (outermost_loop_in_sese_1): Moved and renamed...
	(try_generate_gimple_bb): Call outermost_loop_in_sese.
	(analyze_drs_in_stmts): Same.
	* sese.c (outermost_loop_in_sese): ...here.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@228347 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 27 insertions, 1 deletions

diff --git a/gcc/sese.c b/gcc/sese.c
index ed45410fadd..803f519c1f5 100644
--- a/gcc/sese.c
+++ b/gcc/sese.c
@@ -615,7 +615,7 @@ copy_bb_and_scalar_dependences (basic_block bb, sese region,
 /* Returns the outermost loop in SCOP that contains BB.  */
 
 struct loop *
-outermost_loop_in_sese (sese region, basic_block bb)
+outermost_loop_in_sese_1 (sese region, basic_block bb)
 {
   struct loop *nest;
 
@@ -627,6 +627,32 @@ outermost_loop_in_sese (sese region, basic_block bb)
   return nest;
 }
 
+/* Same as outermost_loop_in_sese_1, returns the outermost loop
+   containing BB in REGION, but makes sure that the returned loop
+   belongs to the REGION, and so this returns the first loop in the
+   REGION when the loop containing BB does not belong to REGION.  */
+
+loop_p
+outermost_loop_in_sese (sese region, basic_block bb)
+{
+  loop_p nest = outermost_loop_in_sese_1 (region, bb);
+
+  if (loop_in_sese_p (nest, region))
+    return nest;
+
+  /* When the basic block BB does not belong to a loop in the region,
+     return the first loop in the region.  */
+  nest = nest->inner;
+  while (nest)
+    if (loop_in_sese_p (nest, region))
+      break;
+    else
+      nest = nest->next;
+
+  gcc_assert (nest);
+  return nest;
+}
+
 /* Sets the false region of an IF_REGION to REGION.  */
 
 void