Add hint if the fallthrough target of current BB isn't the one

placed closely next.

2019-07-12  Kewen Lin  <linkw@gcc.gnu.org>

    * gcc/cfgrtl.c (print_rtl_with_bb): Emit a hint if the
    fallthrough target of current basic block isn't the placed
    right next.

From-SVN: r273430

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 3d92250b520eaf09cbb6ea12eb3e0125829253f2..d4eaa491a10e324ae2cb21f6645da4681cd2829b 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2019-07-12  Kewen Lin  <linkw@gcc.gnu.org>
+
+       * gcc/cfgrtl.c (print_rtl_with_bb): Emit a hint if the
+       fallthrough target of current basic block isn't the placed
+       right next.
+
 2019-07-11  Sunil K Pandey  <sunil.k.pandey@intel.com>
 
        PR target/90980

diff --git a/gcc/cfgrtl.c b/gcc/cfgrtl.c
index 4853ce4713dec04562f276aae50d80c8af088f8f..bdef400537d6b54d13a37f35898c33780a9eead9 100644 (file)
--- a/gcc/cfgrtl.c
+++ b/gcc/cfgrtl.c
@@ -2198,7 +2198,7 @@ print_rtl_with_bb (FILE *outf, const rtx_insn *rtx_first, dump_flags_t flags)
       if (df)
        df_dump_start (outf);
 
-      if (flags & TDF_BLOCKS)
+      if (cfun->curr_properties & PROP_cfg)
        {
          FOR_EACH_BB_REVERSE_FN (bb, cfun)
            {
@@ -2206,16 +2206,19 @@ print_rtl_with_bb (FILE *outf, const rtx_insn *rtx_first, dump_flags_t flags)
 
              start[INSN_UID (BB_HEAD (bb))] = bb;
              end[INSN_UID (BB_END (bb))] = bb;
-             for (x = BB_HEAD (bb); x != NULL_RTX; x = NEXT_INSN (x))
+             if (flags & TDF_BLOCKS)
                {
-                 enum bb_state state = IN_MULTIPLE_BB;
+                 for (x = BB_HEAD (bb); x != NULL_RTX; x = NEXT_INSN (x))
+                   {
+                     enum bb_state state = IN_MULTIPLE_BB;
 
-                 if (in_bb_p[INSN_UID (x)] == NOT_IN_BB)
-                   state = IN_ONE_BB;
-                 in_bb_p[INSN_UID (x)] = state;
+                     if (in_bb_p[INSN_UID (x)] == NOT_IN_BB)
+                       state = IN_ONE_BB;
+                     in_bb_p[INSN_UID (x)] = state;
 
-                 if (x == BB_END (bb))
-                   break;
+                     if (x == BB_END (bb))
+                       break;
+                   }
                }
            }
        }
@@ -2249,16 +2252,36 @@ print_rtl_with_bb (FILE *outf, const rtx_insn *rtx_first, dump_flags_t flags)
          if (flags & TDF_DETAILS)
            df_dump_insn_bottom (tmp_rtx, outf);
 
-         if (flags & TDF_BLOCKS)
+         bb = end[INSN_UID (tmp_rtx)];
+         if (bb != NULL)
            {
-             bb = end[INSN_UID (tmp_rtx)];
-             if (bb != NULL)
+             if (flags & TDF_BLOCKS)
                {
                  dump_bb_info (outf, bb, 0, dump_flags, false, true);
                  if (df && (flags & TDF_DETAILS))
                    df_dump_bottom (bb, outf);
                  putc ('\n', outf);
                }
+             /* Emit a hint if the fallthrough target of current basic block
+                isn't the one placed right next.  */
+             else if (EDGE_COUNT (bb->succs) > 0)
+               {
+                 gcc_assert (BB_END (bb) == tmp_rtx);
+                 const rtx_insn *ninsn = NEXT_INSN (tmp_rtx);
+                 /* Bypass intervening deleted-insn notes and debug insns.  */
+                 while (ninsn
+                        && !NONDEBUG_INSN_P (ninsn)
+                        && !start[INSN_UID (ninsn)])
+                   ninsn = NEXT_INSN (ninsn);
+                 edge e = find_fallthru_edge (bb->succs);
+                 if (e && ninsn)
+                   {
+                     basic_block dest = e->dest;
+                     if (start[INSN_UID (ninsn)] != dest)
+                       fprintf (outf, "%s      ; pc falls through to BB %d\n",
+                                print_rtx_head, dest->index);
+                   }
+               }
            }
        }