2012-03-28 Richard Guenther <rguenther@suse.de>

	* loop-init.c (loop_optimizer_init): If loops are preserved
	perform incremental initialization of required loop features.
	(loop_optimizer_finalize): If loops are to be preserved only
	clean up optional loop features.
	(rtl_loop_done): Forcefully free loops here.
	* cgraph.c (cgraph_release_function_body): Forcefully free
	loops.
	* cfgexpand.c (expand_gimple_cond): Properly add new basic-blocks
	to existing loops.
	(construct_init_block): Likewise.
	(construct_exit_block): Likewise.
	(gimple_expand_cfg): Clear LOOP_CLOSED_SSA loop state.  Cleanup
	the CFG after expanding.
	* cfgloop.c (verify_loop_structure): Calculate or verify
	dominators.  If we needed to calculate them, free them afterwards.
	* tree-pass.h (PROP_loops): New define.
	* tree-ssa-loop.c (pass_tree_loop_init): Provide PROP_loops.
	* basic-block.h (CLEANUP_CFG_CHANGED): New.
	* cfgcleanup.c (merge_blocks_move): Protect loop latches.
	(cleanup_cfg): If we did something and have loops around, fix
	them up.
	* cse.c (rest_of_handle_cse_after_global_opts): Call cleanup_cfg
	with CLEANUP_CFG_CHANGED.
	* cfghooks.c (merge_blocks): If we merge a loop header into
	its predecessor, update the loop structure.
	(duplicate_block): If we copy a loop latch, adjust loop state
	to note we may have multiple latches.
	(delete_basic_block): Mark loops for fixup if we remove a loop.
	* cfganal.c (forwarder_block_p): Protect loop latches, headers
	and preheaders.
	* cfgrtl.c (rtl_can_merge_blocks): Protect loop latches.
	(cfg_layout_can_merge_blocks_p): Likewise.
	* cprop.c (bypass_block): If we create a loop with multiple
	entries, mark it for removal.
	* except.c (emit_to_new_bb_before): Add the new basic-block
	to existing loops.
	* tree-eh.c (lower_resx): Likewise.
	* omp-low.c (finalize_task_copyfn): Do not copy PROP_loops.
	(expand_omp_taskreg): Likewise.
	* tree-inline.c (initialize_cfun): Likewise.
	* tree-mudflap.c (add_bb_to_loop): Prototype.
	(mf_build_check_statement_for): Properly add new basic-blocks
	to existing loops.
	* tree-ssa-threadupdate.c (thread_block): Mark loops for fixup
	if we remove a loop.
	(thread_through_loop_header): Likewise.
	* trans-mem.c (tm_log_emit_save_or_restores): Properly add
	new basic-blocks to existing loops.
	(expand_transaction): Likewise.
	* Makefile.in (except.o): Add $(CFGLOOP_H).
	(expr.o): Likewise.
	(cgraph.o): Likewise.
	(cprop.o): Likewise.
	(cfgexpand.o): Likewise.
	(cfganal.o): Likewise.
	(trans-mem.o): Likewise.
	(tree-eh.o): Likewise.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@185913 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 24 insertions, 1 deletions

diff --git a/gcc/cfghooks.c b/gcc/cfghooks.c
index c4c51cc4404..1dca79a70cf 100644
--- a/gcc/cfghooks.c
+++ b/gcc/cfghooks.c
@@ -508,6 +508,7 @@ delete_basic_block (basic_block bb)
 	{
 	  loop->header = NULL;
 	  loop->latch = NULL;
+	  loops_state_set (LOOPS_NEED_FIXUP);
 	}
 
       remove_bb_from_loops (bb);
@@ -682,8 +683,18 @@ merge_blocks (basic_block a, basic_block b)
 
   cfg_hooks->merge_blocks (a, b);
 
+  /* If we merge a loop header into its predecessor, update the loop
+     structure.  */
   if (current_loops != NULL)
-    remove_bb_from_loops (b);
+    {
+      if (b->loop_father->header == b)
+	{
+	  remove_bb_from_loops (a);
+	  add_bb_to_loop  (a, b->loop_father);
+	  a->loop_father->header = a;
+	}
+      remove_bb_from_loops (b);
+    }
 
   /* Normally there should only be one successor of A and that is B, but
      partway though the merge of blocks for conditional_execution we'll
@@ -999,6 +1010,18 @@ duplicate_block (basic_block bb, edge e, basic_block after)
       struct loop *cloop = bb->loop_father;
       struct loop *copy = get_loop_copy (cloop);
       add_bb_to_loop (new_bb, copy ? copy : cloop);
+      /* If we copied the loop latch block but not the loop, adjust
+	 loop state.
+	 ???  If we copied the loop header block but not the loop
+	 we might either have created a loop copy or a loop with
+	 multiple entries.  In both cases we probably have to
+	 ditch the loops and arrange for a fixup.  */
+      if (!copy
+	  && cloop->latch == bb)
+	{
+	  cloop->latch = NULL;
+	  loops_state_set (LOOPS_MAY_HAVE_MULTIPLE_LATCHES);
+	}
     }
 
   return new_bb;