[PATCH] Fix FAIL: gfortran.dg/graphite/pr68279.f90 -O (internal compiler error) (PR77318)

[Richard Biener <rguenther at suse dot de>]

The following patch fixes the graphite ICE in the fortran testsuite.
After digging and reverse engineering I concluded that the loop
passed to scalar_evolution_in_region via add_condition_to_pbb
and create_pw_aff_from_tree is bogus and instead the loop of the
condition stmt should be used to not get chrecs with evolutions in
loops that are not inside the SESE region of the SCOP.  This in
turn causes to trigger the assert because scalar_evolution_in_region
doesn't "instantiate" defs in the region (but not defined in a loop
fully contained in the region) up to parameters of the region.
So what we are really interested in is that SSA names _not_ defined
in the SESE region are registered as parameters.

Bootstrap and regtest running on x86_64-unknown-linux-gnu,
preliminary testing on all graphite.exp with {,-m32} passed
(I guess that's what we have in test coverage).

I've come up with this through reverse-engineering only, knowing
nothing about graphite so I'd appreciate a OK from the CCed
maintainers (well, "maintainers"...)

I'll try a quick before/after test of -floop-nest-optimize on SPEC 2k6.

Thanks,
Richard.

2017-01-31  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/77318
	* graphite-sese-to-poly.c (extract_affine): Fix assert.
	(create_pw_aff_from_tree): Take loop parameter.
	(add_condition_to_pbb): Pass loop of the condition to
	create_pw_aff_from_tree.

Index: gcc/graphite-sese-to-poly.c
===================================================================
--- gcc/graphite-sese-to-poly.c	(revision 245052)
+++ gcc/graphite-sese-to-poly.c	(working copy)
@@ -407,7 +407,7 @@ extract_affine (scop_p s, tree e, __isl_
 
     case SSA_NAME:
       gcc_assert (-1 != parameter_index_in_region_1 (e, s->scop_info)
-		  || !invariant_in_sese_p_rec (e, s->scop_info->region, NULL));
+		  || defined_in_sese_p (e, s->scop_info->region));
       res = extract_affine_name (s, e, space);
       break;
 
@@ -436,11 +436,11 @@ extract_affine (scop_p s, tree e, __isl_
 /* Returns a linear expression for tree T evaluated in PBB.  */
 
 static isl_pw_aff *
-create_pw_aff_from_tree (poly_bb_p pbb, tree t)
+create_pw_aff_from_tree (poly_bb_p pbb, loop_p loop, tree t)
 {
   scop_p scop = PBB_SCOP (pbb);
 
-  t = scalar_evolution_in_region (scop->scop_info->region, pbb_loop (pbb), t);
+  t = scalar_evolution_in_region (scop->scop_info->region, loop, t);
 
   gcc_assert (!chrec_contains_undetermined (t));
   gcc_assert (!automatically_generated_chrec_p (t));
@@ -455,8 +455,9 @@ create_pw_aff_from_tree (poly_bb_p pbb,
 static void
 add_condition_to_pbb (poly_bb_p pbb, gcond *stmt, enum tree_code code)
 {
-  isl_pw_aff *lhs = create_pw_aff_from_tree (pbb, gimple_cond_lhs (stmt));
-  isl_pw_aff *rhs = create_pw_aff_from_tree (pbb, gimple_cond_rhs (stmt));
+  loop_p loop = gimple_bb (stmt)->loop_father;
+  isl_pw_aff *lhs = create_pw_aff_from_tree (pbb, loop, gimple_cond_lhs (stmt));
+  isl_pw_aff *rhs = create_pw_aff_from_tree (pbb, loop, gimple_cond_rhs (stmt));
 
   isl_set *cond;
   switch (code)