re PR tree-optimization/82451 ([GRAPHITE] codegen error in get_rename_from_scev)

2017-10-13  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/82451
	Revert
	2017-10-02  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/82355
	* graphite-isl-ast-to-gimple.c (build_iv_mapping): Also build
	a mapping for the enclosing loop but avoid generating one for
	the loop tree root.
	(copy_bb_and_scalar_dependences): Remove premature codegen
	error on PHIs in blocks duplicated into multiple places.
	* graphite-scop-detection.c
	(scop_detection::stmt_has_simple_data_refs_p): For a loop not
	in the region use it as loop and nest to analyze the DR in.
	(try_generate_gimple_bb): Likewise.
	* graphite-sese-to-poly.c (extract_affine_chrec): Adjust.
	(add_loop_constraints): For blocks in a loop not in the region
	create a dimension with a single iteration.
	* sese.h (gbb_loop_at_index): Remove assert.

	* cfgloop.c (loop_preheader_edge): For the loop tree root
	return the single successor of the entry block.
	* graphite-isl-ast-to-gimple.c (graphite_regenerate_ast_isl):
	Reset the SCEV hashtable and niters.
	* graphite-scop-detection.c
	(scop_detection::graphite_can_represent_scev): Add SCOP parameter,
	assert that we only have POLYNOMIAL_CHREC that vary in loops
	contained in the region.
	(scop_detection::graphite_can_represent_expr): Adjust.
	(scop_detection::stmt_has_simple_data_refs_p): For loops
	not in the region set loop to NULL.  The nest is now the
	entry edge to the region.
	(try_generate_gimple_bb): Likewise.
	* sese.c (scalar_evolution_in_region): Adjust for
	instantiate_scev change.
	* tree-data-ref.h (graphite_find_data_references_in_stmt):
	Make nest parameter the edge into the region.
	(create_data_ref): Likewise.
	* tree-data-ref.c (dr_analyze_indices): Make nest parameter an
	entry edge into a region and adjust instantiate_scev calls.
	(create_data_ref): Likewise.
	(graphite_find_data_references_in_stmt): Likewise.
	(find_data_references_in_stmt): Pass the loop preheader edge
	from the nest argument.
	* tree-scalar-evolution.h (instantiate_scev): Make instantiate_below
	parameter the edge into the region.
	(instantiate_parameters): Use the loop preheader edge as entry.
	* tree-scalar-evolution.c (analyze_scalar_evolution): Handle
	NULL loop.
	(get_instantiated_value_entry): Make instantiate_below parameter
	the edge into the region.
	(instantiate_scev_name): Likewise.  Adjust dominance checks,
	when we cannot use loop-based instantiation instantiate by
	walking use-def chains.
	(instantiate_scev_poly): Adjust.
	(instantiate_scev_binary): Likewise.
	(instantiate_scev_convert): Likewise.
	(instantiate_scev_not): Likewise.
	(instantiate_array_ref): Remove.
	(instantiate_scev_3): Likewise.
	(instantiate_scev_2): Likewise.
	(instantiate_scev_1): Likewise.
	(instantiate_scev_r): Do not blindly handle N-operand trees.
	Do not instantiate array-refs.  Handle all constants and invariants.
	(instantiate_scev): Make instantiate_below parameter
	the edge into the region.
	(resolve_mixers): Use the loop preheader edge for the region
	parameter to instantiate_scev_r.
	* tree-ssa-loop-prefetch.c (determine_loop_nest_reuse): Adjust.

	* gcc.dg/graphite/pr82451.c: New testcase.
	* gfortran.dg/graphite/id-27.f90: Likewise.
	* gfortran.dg/graphite/pr82451.f: Likewise.

From-SVN: r253707

1 files changed, 8 insertions, 4 deletions

diff --git a/gcc/graphite-isl-ast-to-gimple.c b/gcc/graphite-isl-ast-to-gimple.c
index 9a9f8c8..8749418 100644
--- a/gcc/graphite-isl-ast-to-gimple.c
+++ b/gcc/graphite-isl-ast-to-gimple.c
@@ -750,10 +750,8 @@ build_iv_mapping (vec<tree> iv_map, gimple_poly_bb_p gbb,
       if (codegen_error_p ())
 	t = integer_zero_node;
 
-      loop_p old_loop = gbb_loop_at_index (gbb, region, i - 2);
-      /* Record sth only for real loops.  */
-      if (loop_in_sese_p (old_loop, region))
-	iv_map[old_loop->num] = t;
+      loop_p old_loop = gbb_loop_at_index (gbb, region, i - 1);
+      iv_map[old_loop->num] = t;
     }
 }
 
@@ -1571,6 +1569,12 @@ graphite_regenerate_ast_isl (scop_p scop)
       update_ssa (TODO_update_ssa);
       checking_verify_ssa (true, true);
       rewrite_into_loop_closed_ssa (NULL, 0);
+      /* We analyzed evolutions of all SCOPs during SCOP detection
+         which cached evolutions.  Now we've introduced PHIs for
+	 liveouts which causes those cached solutions to be invalid
+	 for code-generation purposes given we'd insert references
+	 to SSA names not dominating their new use.  */
+      scev_reset ();
     }
 
   if (t.codegen_error_p ())