Backwards jump threader rewrite with ranger.

This is a rewrite of the backwards threader with a ranger based solver.

The code is divided into two parts: the path solver in
gimple-range-path.*, and the path discovery bits in
tree-ssa-threadbackward.c.

The legacy code is still available with --param=threader-mode=legacy,
but will be removed shortly after.

gcc/ChangeLog:

	* Makefile.in (tree-ssa-loop-im.o-warn): New.
	* flag-types.h (enum threader_mode): New.
	* params.opt: Add entry for --param=threader-mode.
	* tree-ssa-threadbackward.c (THREADER_ITERATIVE_MODE): New.
	(class back_threader): New.
	(back_threader::back_threader): New.
	(back_threader::~back_threader): New.
	(back_threader::maybe_register_path): New.
	(back_threader::find_taken_edge): New.
	(back_threader::find_taken_edge_switch): New.
	(back_threader::find_taken_edge_cond): New.
	(back_threader::resolve_def): New.
	(back_threader::resolve_phi): New.
	(back_threader::find_paths_to_names): New.
	(back_threader::find_paths): New.
	(dump_path): New.
	(debug): New.
	(thread_jumps::find_jump_threads_backwards): Call ranger threader.
	(thread_jumps::find_jump_threads_backwards_with_ranger): New.
	(pass_thread_jumps::execute): Abstract out code...
	(try_thread_blocks): ...here.
	* tree-ssa-threadedge.c (jump_threader::thread_outgoing_edges):
	Abstract out threading candidate code to...
	(single_succ_to_potentially_threadable_block): ...here.
	* tree-ssa-threadedge.h (single_succ_to_potentially_threadable_block):
	New.
	* tree-ssa-threadupdate.c (register_jump_thread): Return boolean.
	* tree-ssa-threadupdate.h (class jump_thread_path_registry):
	Return bool from register_jump_thread.

libgomp/ChangeLog:

	* testsuite/libgomp.graphite/force-parallel-4.c: Adjust for
	threader.
	* testsuite/libgomp.graphite/force-parallel-8.c: Same.

gcc/testsuite/ChangeLog:

	* g++.dg/debug/dwarf2/deallocator.C: Adjust for threader.
	* gcc.c-torture/compile/pr83510.c: Same.
	* dg.dg/analyzer/pr94851-2.c: Same.
	* gcc.dg/loop-unswitch-2.c: Same.
	* gcc.dg/old-style-asm-1.c: Same.
	* gcc.dg/pr68317.c: Same.
	* gcc.dg/pr97567-2.c: Same.
	* gcc.dg/predict-9.c: Same.
	* gcc.dg/shrink-wrap-loop.c: Same.
	* gcc.dg/sibcall-1.c: Same.
	* gcc.dg/tree-ssa/builtin-sprintf-3.c: Same.
	* gcc.dg/tree-ssa/pr21001.c: Same.
	* gcc.dg/tree-ssa/pr21294.c: Same.
	* gcc.dg/tree-ssa/pr21417.c: Same.
	* gcc.dg/tree-ssa/pr21458-2.c: Same.
	* gcc.dg/tree-ssa/pr21563.c: Same.
	* gcc.dg/tree-ssa/pr49039.c: Same.
	* gcc.dg/tree-ssa/pr61839_1.c: Same.
	* gcc.dg/tree-ssa/pr61839_3.c: Same.
	* gcc.dg/tree-ssa/pr77445-2.c: Same.
	* gcc.dg/tree-ssa/split-path-4.c: Same.
	* gcc.dg/tree-ssa/ssa-dom-thread-11.c: Same.
	* gcc.dg/tree-ssa/ssa-dom-thread-12.c: Same.
	* gcc.dg/tree-ssa/ssa-dom-thread-14.c: Same.
	* gcc.dg/tree-ssa/ssa-dom-thread-18.c: Same.
	* gcc.dg/tree-ssa/ssa-dom-thread-6.c: Same.
	* gcc.dg/tree-ssa/ssa-dom-thread-7.c: Same.
	* gcc.dg/tree-ssa/ssa-fre-48.c: Same.
	* gcc.dg/tree-ssa/ssa-thread-11.c: Same.
	* gcc.dg/tree-ssa/ssa-thread-12.c: Same.
	* gcc.dg/tree-ssa/ssa-thread-14.c: Same.
	* gcc.dg/tree-ssa/vrp02.c: Same.
	* gcc.dg/tree-ssa/vrp03.c: Same.
	* gcc.dg/tree-ssa/vrp05.c: Same.
	* gcc.dg/tree-ssa/vrp06.c: Same.
	* gcc.dg/tree-ssa/vrp07.c: Same.
	* gcc.dg/tree-ssa/vrp09.c: Same.
	* gcc.dg/tree-ssa/vrp19.c: Same.
	* gcc.dg/tree-ssa/vrp20.c: Same.
	* gcc.dg/tree-ssa/vrp33.c: Same.
	* gcc.dg/uninit-pred-9_b.c: Same.
	* gcc.dg/uninit-pr61112.c: Same.
	* gcc.dg/vect/bb-slp-16.c: Same.
	* gcc.target/i386/avx2-vect-aggressive.c: Same.
	* gcc.dg/tree-ssa/ranger-threader-1.c: New test.
	* gcc.dg/tree-ssa/ranger-threader-2.c: New test.
	* gcc.dg/tree-ssa/ranger-threader-3.c: New test.
	* gcc.dg/tree-ssa/ranger-threader-4.c: New test.
	* gcc.dg/tree-ssa/ranger-threader-5.c: New test.

1 files changed, 14 insertions, 6 deletions

diff --git a/gcc/tree-ssa-threadedge.c b/gcc/tree-ssa-threadedge.c
index 24ccf01..37ee5c1 100644
--- a/gcc/tree-ssa-threadedge.c
+++ b/gcc/tree-ssa-threadedge.c
@@ -1261,6 +1261,18 @@ jump_threader::thread_across_edge (edge e)
   m_state->pop ();
 }
 
+/* Return TRUE if BB has a single successor to a block with multiple
+   incoming and outgoing edges.  */
+
+bool
+single_succ_to_potentially_threadable_block (basic_block bb)
+{
+  int flags = (EDGE_IGNORE | EDGE_COMPLEX | EDGE_ABNORMAL);
+  return (single_succ_p (bb)
+	  && (single_succ_edge (bb)->flags & flags) == 0
+	  && potentially_threadable_block (single_succ (bb)));
+}
+
 /* Examine the outgoing edges from BB and conditionally
    try to thread them.  */
 
@@ -1274,12 +1286,8 @@ jump_threader::thread_outgoing_edges (basic_block bb)
      outgoing edges, then we may be able to thread the edge, i.e., we
      may be able to statically determine which of the outgoing edges
      will be traversed when the incoming edge from BB is traversed.  */
-  if (single_succ_p (bb)
-      && (single_succ_edge (bb)->flags & flags) == 0
-      && potentially_threadable_block (single_succ (bb)))
-    {
-      thread_across_edge (single_succ_edge (bb));
-    }
+  if (single_succ_to_potentially_threadable_block (bb))
+    thread_across_edge (single_succ_edge (bb));
   else if ((last = last_stmt (bb))
 	   && gimple_code (last) == GIMPLE_COND
 	   && EDGE_COUNT (bb->succs) == 2