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

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