tree-cfg.c (execute_build_cfg): Build the loop tree.

2013-03-26  Richard Biener  <rguenther@suse.de>

	* tree-cfg.c (execute_build_cfg): Build the loop tree.
	(pass_build_cfg): Provide PROP_loops.
	(move_sese_region_to_fn): Remove loops that are outlined into fn
	for now.
	* tree-inline.c: Include cfgloop.h.
	(initialize_cfun): Do not drop PROP_loops.
	(copy_loops): New function.
	(copy_cfg_body): Copy loop structure.
	(tree_function_versioning): Initialize destination loop tree.
	* tree-ssa-loop.c (pass_tree_loop_init): Do not provide PROP_loops.
	(pass_parallelize_loops): Do IL verification.
	* loop-init.c (loop_optimizer_init): Fixup loops if required.
	* tree-optimize.c (execute_fixup_cfg): If we need to cleanup
	the CFG make sure we fixup loops as well.
	* tree-ssa-tail-merge.c: Include cfgloop.h.
	(replace_block_by): When merging loop latches mark loops for fixup.
	* lto-streamer-out.c (output_struct_function_base): Drop
	PROP_loops for now.
	* tree-ssa-phiopt.c: Include tree-scalar-evolution.h.
	(tree_ssa_cs_elim): Initialize the loop optimizer and SCEV.
	* ipa-split.c: Include cfgloop.h.
	(split_function): Add the new return block to the loop tree root.
	* tree-cfgcleanup.c (remove_forwarder_block_with_phi): Return
	whether we have removed the forwarder block.
	(merge_phi_nodes): If we removed a forwarder mark loops for fixup.
	* cfgloop.h (place_new_loop): Declare.
	* cfgloopmanip.c (place_new_loop): Export.
	* Makefile.in (asan.o): Add $(CFGLOOP_H) dependency.
	(tree-switch-conversion.o): Likewise.
	(tree-complex.o): Likewise.
	(tree-inline.o): Likewise.
	(tree-ssa-tailmerge.o): Likewise.
	(ipa-split.o): Likewise.
	(tree-ssa-phiopt.o): Add $(SCEV_H) dependency.
	(tree-ssa-copy.o): Likewise.
	* tree-switch-conversion.c: Include cfgloop.h
	(process_switch): If we emit a bit-test cascade, schedule loops
	for fixup.
	* tree-complex.c: Include cfgloop.h.
	(expand_complex_div_wide): Properly add new basic-blocks to loops.
	* asan.c: Include cfgloop.h.
	(create_cond_insert_point): Properly add new basic-blocks to
	loops, schedule loop fixup.
	* cfgloop.c (verify_loop_structure): Check that looks are not
	marked for fixup.
	* omp-low.c (expand_parallel_call): Properly add new basic-blocks
	to loops.
	(expand_omp_for_generic): Likewise.
	(expand_omp_sections): Likewise.
	(expand_omp_atomic_pipeline): Schedule loops for fixup.
	* tree-ssa-copy.c: Include tree-scalar-evolution.h.
	(fini_copy_prop): Disable DCE in substitute_and_fold if SCEV
	is initialized, not when loops are present.
	* tree-parloops.c (parallelize_loops): Remove checking here.
	* passes.c (init_optimization_passes): Schedule a copy-propagation
	pass before complete unrolling of inner loops.

	* gcc.dg/tree-prof/update-loopch.c: Revert last change.
	* gcc.dg/graphite/pr33766.c: Fix undefined behavior.
	* gcc.dg/pr53265.c: Remove XFAILs.
	* gcc.dg/tree-ssa/loop-38.c: Remove unreliable dump scanning.
	* gcc.dg/tree-ssa/pr21559.c: Change back to two expected jump threads.

From-SVN: r198333

1 files changed, 16 insertions, 6 deletions

diff --git a/gcc/tree-cfgcleanup.c b/gcc/tree-cfgcleanup.c
index b355a86..3c69a7d 100644
--- a/gcc/tree-cfgcleanup.c
+++ b/gcc/tree-cfgcleanup.c
@@ -748,9 +748,10 @@ cleanup_tree_cfg (void)
   return changed;
 }
 
-/* Merge the PHI nodes at BB into those at BB's sole successor.  */
+/* Tries to merge the PHI nodes at BB into those at BB's sole successor.
+   Returns true if successful.  */
 
-static void
+static bool
 remove_forwarder_block_with_phi (basic_block bb)
 {
   edge succ = single_succ_edge (bb);
@@ -762,7 +763,7 @@ remove_forwarder_block_with_phi (basic_block bb)
      However it may happen that the infinite loop is created
      afterwards due to removal of forwarders.  */
   if (dest == bb)
-    return;
+    return false;
 
   /* If the destination block consists of a nonlocal label, do not
      merge it.  */
@@ -770,7 +771,7 @@ remove_forwarder_block_with_phi (basic_block bb)
   if (label
       && gimple_code (label) == GIMPLE_LABEL
       && DECL_NONLOCAL (gimple_label_label (label)))
-    return;
+    return false;
 
   /* Redirect each incoming edge to BB to DEST.  */
   while (EDGE_COUNT (bb->preds) > 0)
@@ -859,6 +860,8 @@ remove_forwarder_block_with_phi (basic_block bb)
   /* Remove BB since all of BB's incoming edges have been redirected
      to DEST.  */
   delete_basic_block (bb);
+
+  return true;
 }
 
 /* This pass merges PHI nodes if one feeds into another.  For example,
@@ -960,13 +963,20 @@ merge_phi_nodes (void)
     }
 
   /* Now let's drain WORKLIST.  */
+  bool changed = false;
   while (current != worklist)
     {
       bb = *--current;
-      remove_forwarder_block_with_phi (bb);
+      changed |= remove_forwarder_block_with_phi (bb);
     }
-
   free (worklist);
+
+  /* Removing forwarder blocks can cause formerly irreducible loops
+     to become reducible if we merged two entry blocks.  */
+  if (changed
+      && current_loops)
+    loops_state_set (LOOPS_NEED_FIXUP);
+
   return 0;
 }