re PR debug/54551 (DF resets some DEBUG_INSNs unnecessarily)

PR debug/54551
PR debug/54693
* valtrack.c (dead_debug_promote_uses): Assert-check that
global used bit was clear and initialize entry
unconditionally.

From-SVN: r193003

gcc/ChangeLog

+2012-10-30  Alexandre Oliva <aoliva@redhat.com>
+
+	PR debug/54551
+	PR debug/54693
+	* valtrack.c (dead_debug_promote_uses): Assert-check that
+	global used bit was clear and initialize entry
+	unconditionally.
+
 2012-10-30  Eric Botcazou  <ebotcazou@adacore.com>
 
 	* cse.c (hash_rtx_cb): Replace RTX_UNCHANGING_P with MEM_READONLY_P in

gcc/valtrack.c

@@ -380,9 +380,11 @@ dead_debug_promote_uses (struct dead_debug_local *debug)
       if (!debug->global->used)
 	debug->global->used = BITMAP_ALLOC (NULL);
 
-      if (bitmap_set_bit (debug->global->used, REGNO (reg)))
-	entry = dead_debug_global_insert (debug->global, reg,
-					  make_debug_expr_from_rtl (reg));
+      bool added = bitmap_set_bit (debug->global->used, REGNO (reg));
+      gcc_checking_assert (added);
+
+      entry = dead_debug_global_insert (debug->global, reg,
+					make_debug_expr_from_rtl (reg));
 
       gcc_checking_assert (entry->dtemp);