[SFN] not-quite-boilerplate changes in preparation to introduce nonbind markers

This patch adjusts numerous parts of the compiler that would
malfunction should they find debug markers at points where they may be
introduced.  The changes purport to allow the compiler to pass
bootstrap-debug-lean (-fcompare-debug in stage3) at various
optimization levels, as well as bootstrap-debug-lib (-fcompare-debug
for target libraries), even after the compiler is changed so that
debug markers are introduced in code streams at spots where earlier
debug stmts, insns and notes wouldn't normally appear.

This patch depends on an earlier SFN boilerplate patch, and on another
SFN patch that introduces new RTL insn-walking functions.

for  gcc/ChangeLog

	* cfgcleanup.c (delete_unreachable_blocks): Use alternate
	block removal order if MAY_HAVE_DEBUG_BIND_INSNS.
	* cfgexpand.c (label_rtx_for_bb): Skip debug insns.
	* cfgrtl.c (try_redirect_by_replacing_jump): Skip debug insns.
	(rtl_tidy_fallthru_edge): Likewise.
	(rtl_verify_fallthru): Likewise.
	(rtl_verify_bb_layout): Likewise.
	(skip_insns_after_block): Likewise.
	(duplicate_insn_chain): Use DEBUG_BIND_INSN_P.
	* dwarf2out.c: Include print-rtl.h.
	(dwarf2out_next_real_insn): New.
	(dwarf2out_var_location): Call it.  Disregard begin stmt markers.
	Dump debug binds in asm comments.
	* gimple-iterator.c (gimple_find_edge_insert_loc): Skip debug stmts.
	* gimple-iterator.h (gsi_start_bb_nondebug): Remove; adjust
	callers to use gsi_start_nondebug_bb instead.
	(gsi_after_labels): Skip gimple debug stmts.
	(gsi_start_nondebug): New.
	* gimple-loop-interchange.c (find_deps_in_bb_for_stmt): Adjust.
	(proper_loop_form_for_interchange): Adjust.
	* gimple-low.c (gimple_seq_may_fallthru): Take last nondebug stmt.
	* gimple.h (gimple_seq_last_nondebug_stmt): New.
	* gimplify.c (last_stmt_in_scope): Skip debug stmts.
	(collect_fallthrough_labels): Likewise.
	(should_warn_for_implicit_fallthrough): Likewise.
	(warn_implicit_fallthrough_r): Likewise.
	(expand_FALLTHROUGH_r): Likewise.
	* graphite-isl-ast-to-gimple.c (gsi_insert_earliest): Adjust.
	(graphite_copy_stmts_from_block): Skip nonbind markers.
	* haifa-sched.c (sched_extend_bb): Skip debug insns.
	* ipa-icf-gimple.c (func_checker::compare_bb): Adjust.
	* jump.c (clean_barriers): Skip debug insns.
	* omp-expand.c (expand_parallel_call): Skip debug insns.
	(expand_task_call): Likewise.
	(remove_exit_barrier): Likewise.
	(expand_omp_taskreg): Likewise.
	(expand_omp_for_init_counts): Likewise.
	(expand_omp_for_generic): Likewise.
	(expand_omp_for_static_nochunk): Likewise.
	(expand_omp_for_static_chunk): Likewise.
	(expand_omp_simd): Likewise.
	(expand_omp_taskloop_for_outer): Likewise.
	(expand_omp_taskloop_for_inner): Likewise.
	(expand_oacc_for): Likewise.
	(expand_omp_sections): Likewise.
	(expand_omp_single): Likewise.
	(expand_omp_synch): Likewise.
	(expand_omp_atomic_load): Likewise.
	(expand_omp_atomic_store): Likewise.
	(expand_omp_atomic_fetch_op): Likewise.
	(expand_omp_atomic_pipeline): Likewise.
	(expand_omp_atomic_mutex): Likewise.
	(expand_omp_target): Likewise.
	(grid_expand_omp_for_loop): Likewise.
	(grid_expand_target_grid_body): Likewise.
	(build_omp_regions_1): Likewise.
	* omp-low.c (check_combined_parallel): Skip debug stmts.
	* postreload.c (fixup_debug_insns): Skip nonbind debug insns.
	* regcprop.c (find_oldest_value_reg): Ensure REGNO is not a pseudo.
	* sese.c (sese_trivially_empty_bb_p): Call is_gimple_debug in
	test.
	* tree-cfg.c (make_blobs_1): Skip debug stmts.
	(make_edges): Likewise.
	(cleanup_dead_labels): Likewise.
	(gimple_can_merge_blocks_p): Likewise.
	(stmt_starts_bb_p): Likewise.
	(gimple_block_label): Likewise.
	(gimple_redirect_edge_and_branch): Likewise.
	* tree-cfgcleanup.c (remove_forwarder_block): Rearrange skipping
	of debug stmts.
	(execute_cleanup_cfg_post_optimizing): Dump enumerated decls with
	TDF_SLIM.
	* tree-pretty-print (print_declaration): Omit initializer in slim
	dumps.
	* tree-ssa-dce.c (mark_stmt_if_obviously_necessary): Mark begin stmt
	markers.
	(eliminate_unnecessary_stmts): Stabilize block removal order.
	* tree-ssa-tail-merge.c (find_duplicate): Skip debug stmts.
	* var-tracking.c (get_first_insn): New.
	(vt_emit_notes): Call it.
	(vt_initialize): Walk any insns before the first BB.
	(delete_debug_insns): Likewise.

From-SVN: r255566

1 files changed, 20 insertions, 4 deletions

diff --git a/gcc/cfgexpand.c b/gcc/cfgexpand.c
index b1646a5..3ee242df 100644
--- a/gcc/cfgexpand.c
+++ b/gcc/cfgexpand.c
@@ -2327,6 +2327,9 @@ label_rtx_for_bb (basic_block bb ATTRIBUTE_UNUSED)
     {
       glabel *lab_stmt;
 
+      if (is_gimple_debug (gsi_stmt (gsi)))
+	continue;
+
       lab_stmt = dyn_cast <glabel *> (gsi_stmt (gsi));
       if (!lab_stmt)
 	break;
@@ -5454,7 +5457,7 @@ expand_gimple_basic_block (basic_block bb, bool disable_tail_calls)
   gimple_stmt_iterator gsi;
   gimple_seq stmts;
   gimple *stmt = NULL;
-  rtx_note *note;
+  rtx_note *note = NULL;
   rtx_insn *last;
   edge e;
   edge_iterator ei;
@@ -5495,18 +5498,26 @@ expand_gimple_basic_block (basic_block bb, bool disable_tail_calls)
 	}
     }
 
-  gsi = gsi_start (stmts);
+  gsi = gsi_start_nondebug (stmts);
   if (!gsi_end_p (gsi))
     {
       stmt = gsi_stmt (gsi);
       if (gimple_code (stmt) != GIMPLE_LABEL)
 	stmt = NULL;
     }
+  gsi = gsi_start (stmts);
 
+  gimple *label_stmt = stmt;
   rtx_code_label **elt = lab_rtx_for_bb->get (bb);
 
-  if (stmt || elt)
+  if (stmt)
+    /* We'll get to it in the loop below, and get back to
+       emit_label_and_note then.  */
+    ;
+  else if (stmt || elt)
     {
+    emit_label_and_note:
+      gcc_checking_assert (!note);
       last = get_last_insn ();
 
       if (stmt)
@@ -5521,6 +5532,7 @@ expand_gimple_basic_block (basic_block bb, bool disable_tail_calls)
       BB_HEAD (bb) = NEXT_INSN (last);
       if (NOTE_P (BB_HEAD (bb)))
 	BB_HEAD (bb) = NEXT_INSN (BB_HEAD (bb));
+      gcc_assert (LABEL_P (BB_HEAD (bb)));
       note = emit_note_after (NOTE_INSN_BASIC_BLOCK, BB_HEAD (bb));
 
       maybe_dump_rtl_for_gimple_stmt (stmt, last);
@@ -5528,7 +5540,8 @@ expand_gimple_basic_block (basic_block bb, bool disable_tail_calls)
   else
     BB_HEAD (bb) = note = emit_note (NOTE_INSN_BASIC_BLOCK);
 
-  NOTE_BASIC_BLOCK (note) = bb;
+  if (note)
+    NOTE_BASIC_BLOCK (note) = bb;
 
   for (; !gsi_end_p (gsi); gsi_next (&gsi))
     {
@@ -5536,6 +5549,9 @@ expand_gimple_basic_block (basic_block bb, bool disable_tail_calls)
 
       stmt = gsi_stmt (gsi);
 
+      if (stmt == label_stmt)
+	goto emit_label_and_note;
+
       /* If this statement is a non-debug one, and we generate debug
 	 insns, then this one might be the last real use of a TERed
 	 SSA_NAME, but where there are still some debug uses further