cfgrtl.c (fixup_reorder_chain): Do not emit NOPs in DECL_IGNORED_P functions.

	* cfgrtl.c (fixup_reorder_chain): Do not emit NOPs in DECL_IGNORED_P
	functions.
	(rtl_merge_blocks): Likewise.  Do not emit a NOP if the location of
	the edge can be forwarded.
	(cfg_layout_merge_blocks): Likewise.

From-SVN: r261856

2 files changed, 33 insertions, 17 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index d8e1361..902f8df 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,13 @@
 2018-06-21  Eric Botcazou  <ebotcazou@adacore.com>
 
+	* cfgrtl.c (fixup_reorder_chain): Do not emit NOPs in DECL_IGNORED_P
+	functions.
+	(rtl_merge_blocks): Likewise.  Do not emit a NOP if the location of
+	the edge can be forwarded.
+	(cfg_layout_merge_blocks): Likewise.
+
+2018-06-21  Eric Botcazou  <ebotcazou@adacore.com>
+
 	* except.c (finish_eh_generation): Commit edge insertions only after
 	the EH edges have been redirected from post-landing to landing pads.
 
diff --git a/gcc/cfgrtl.c b/gcc/cfgrtl.c
index 19cef22..3b1931d 100644
--- a/gcc/cfgrtl.c
+++ b/gcc/cfgrtl.c
@@ -813,10 +813,14 @@ emit_nop_for_unique_locus_between (basic_block a, basic_block b)
 static void
 rtl_merge_blocks (basic_block a, basic_block b)
 {
+  /* If B is a forwarder block whose outgoing edge has no location, we'll
+     propagate the locus of the edge between A and B onto it.  */
+  const bool forward_edge_locus
+    = (b->flags & BB_FORWARDER_BLOCK) != 0
+      && LOCATION_LOCUS (EDGE_SUCC (b, 0)->goto_locus) == UNKNOWN_LOCATION;
   rtx_insn *b_head = BB_HEAD (b), *b_end = BB_END (b), *a_end = BB_END (a);
   rtx_insn *del_first = NULL, *del_last = NULL;
   rtx_insn *b_debug_start = b_end, *b_debug_end = b_end;
-  bool forwarder_p = (b->flags & BB_FORWARDER_BLOCK) != 0;
   int b_empty = 0;
 
   if (dump_file)
@@ -887,9 +891,11 @@ rtl_merge_blocks (basic_block a, basic_block b)
   BB_HEAD (b) = b_empty ? NULL : b_head;
   delete_insn_chain (del_first, del_last, true);
 
-  /* When not optimizing and the edge is the only place in RTL which holds
-     some unique locus, emit a nop with that locus in between.  */
-  if (!optimize)
+  /* If not optimizing, preserve the locus of the single edge between
+     blocks A and B if necessary by emitting a nop.  */
+  if (!optimize
+      && !forward_edge_locus
+      && !DECL_IGNORED_P (current_function_decl))
     {
       emit_nop_for_unique_locus_between (a, b);
       a_end = BB_END (a);
@@ -918,9 +924,7 @@ rtl_merge_blocks (basic_block a, basic_block b)
 
   df_bb_delete (b->index);
 
-  /* If B was a forwarder block, propagate the locus on the edge.  */
-  if (forwarder_p
-      && LOCATION_LOCUS (EDGE_SUCC (b, 0)->goto_locus) == UNKNOWN_LOCATION)
+  if (forward_edge_locus)
     EDGE_SUCC (b, 0)->goto_locus = EDGE_SUCC (a, 0)->goto_locus;
 
   if (dump_file)
@@ -3916,9 +3920,9 @@ fixup_reorder_chain (void)
 	force_nonfallthru (e);
     }
 
-  /* Ensure goto_locus from edges has some instructions with that locus
-     in RTL.  */
-  if (!optimize)
+  /* Ensure goto_locus from edges has some instructions with that locus in RTL
+     when not optimizing.  */
+  if (!optimize && !DECL_IGNORED_P (current_function_decl))
     FOR_EACH_BB_FN (bb, cfun)
       {
         edge e;
@@ -4605,7 +4609,11 @@ cfg_layout_can_merge_blocks_p (basic_block a, basic_block b)
 static void
 cfg_layout_merge_blocks (basic_block a, basic_block b)
 {
-  bool forwarder_p = (b->flags & BB_FORWARDER_BLOCK) != 0;
+  /* If B is a forwarder block whose outgoing edge has no location, we'll
+     propagate the locus of the edge between A and B onto it.  */
+  const bool forward_edge_locus
+    = (b->flags & BB_FORWARDER_BLOCK) != 0
+      && LOCATION_LOCUS (EDGE_SUCC (b, 0)->goto_locus) == UNKNOWN_LOCATION;
   rtx_insn *insn;
 
   gcc_checking_assert (cfg_layout_can_merge_blocks_p (a, b));
@@ -4626,9 +4634,11 @@ cfg_layout_merge_blocks (basic_block a, basic_block b)
     try_redirect_by_replacing_jump (EDGE_SUCC (a, 0), b, true);
   gcc_assert (!JUMP_P (BB_END (a)));
 
-  /* When not optimizing and the edge is the only place in RTL which holds
-     some unique locus, emit a nop with that locus in between.  */
-  if (!optimize)
+  /* If not optimizing, preserve the locus of the single edge between
+     blocks A and B if necessary by emitting a nop.  */
+  if (!optimize
+      && !forward_edge_locus
+      && !DECL_IGNORED_P (current_function_decl))
     emit_nop_for_unique_locus_between (a, b);
 
   /* Move things from b->footer after a->footer.  */
@@ -4695,9 +4705,7 @@ cfg_layout_merge_blocks (basic_block a, basic_block b)
 
   df_bb_delete (b->index);
 
-  /* If B was a forwarder block, propagate the locus on the edge.  */
-  if (forwarder_p
-      && LOCATION_LOCUS (EDGE_SUCC (b, 0)->goto_locus) == UNKNOWN_LOCATION)
+  if (forward_edge_locus)
     EDGE_SUCC (b, 0)->goto_locus = EDGE_SUCC (a, 0)->goto_locus;
 
   if (dump_file)