[patch] Bail out if the same label is emitted twice

[Steven Bosscher <stevenb dot gcc at gmail dot com>]

Hello,

Just another small cleanup. This probably made sense before
function-at-a-time became the norm, 10 years ago.

Bootstrapped&tested on powerpc64-unknown-linux-gnu and x86_64-unknown-linux-gnu.
OK for trunk?

Ciao!
Steven


        * emit-rtl.c (emit_label_before): Do not allow the same label
        to be emitted twice.
        (emit_label_after): Likewise.
        (emit_label): Likewise.

Index: emit-rtl.c
===================================================================
--- emit-rtl.c  (revision 189482)
+++ emit-rtl.c  (working copy)
@@ -4221,14 +4221,9 @@ emit_barrier_before (rtx before)
 rtx
 emit_label_before (rtx label, rtx before)
 {
-  /* This can be called twice for the same label as a result of the
-     confusion that follows a syntax error!  So make it harmless.  */
-  if (INSN_UID (label) == 0)
-    {
-      INSN_UID (label) = cur_insn_uid++;
-      add_insn_before (label, before, NULL);
-    }
-
+  gcc_checking_assert (INSN_UID (label) == 0);
+  INSN_UID (label) = cur_insn_uid++;
+  add_insn_before (label, before, NULL);
   return label;
 }

@@ -4387,15 +4382,9 @@ emit_barrier_after (rtx after)
 rtx
 emit_label_after (rtx label, rtx after)
 {
-  /* This can be called twice for the same label
-     as a result of the confusion that follows a syntax error!
-     So make it harmless.  */
-  if (INSN_UID (label) == 0)
-    {
-      INSN_UID (label) = cur_insn_uid++;
-      add_insn_after (label, after, NULL);
-    }
-
+  gcc_checking_assert (INSN_UID (label) == 0);
+  INSN_UID (label) = cur_insn_uid++;
+  add_insn_after (label, after, NULL);
   return label;
 }

@@ -4811,14 +4800,9 @@ emit_call_insn (rtx x)
 rtx
 emit_label (rtx label)
 {
-  /* This can be called twice for the same label
-     as a result of the confusion that follows a syntax error!
-     So make it harmless.  */
-  if (INSN_UID (label) == 0)
-    {
-      INSN_UID (label) = cur_insn_uid++;
-      add_insn (label);
-    }
+  gcc_checking_assert (INSN_UID (label) == 0);
+  INSN_UID (label) = cur_insn_uid++;
+  add_insn (label);
   return label;
 }