re PR middle-end/56729 (ICE in df_insn_delete)

	PR middle-end/56729
	* df-scan.c (df_insn_delete): Disable failing assert.

From-SVN: r197492

gcc/ChangeLog

+2013-04-04  Steven Bosscher  <steven@gcc.gnu.org>
+
+	PR middle-end/56729
+	* df-scan.c (df_insn_delete): Disable failing assert.
+
 2013-04-04  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
 
 	* config/arm/arm-protos.h (arm_builtin_vectorized_function):

gcc/df-scan.c

@@ -1158,8 +1158,17 @@ df_insn_delete (rtx insn)
      In any case, we expect BB to be non-NULL at least up to register
      allocation, so disallow a non-NULL BB up to there.  Not perfect
      but better than nothing...  */
-
+  /* ??? bb can also be NULL if lower-subreg.c:resolve_simple_mov emits
+     an insn into a sequence and then does delete_insn on it.  Not sure
+     if that makes sense, but for now it means this assert cannot work.
+     See PR56738.
+     Disable for now but revisit before the end of GCC 4.9 stage1.  */
+#if 0
   gcc_checking_assert (bb != NULL || reload_completed);
+#else
+  if (bb == NULL)
+    return;
+#endif
 
   df_grow_bb_info (df_scan);
   df_grow_reg_info ();