recog.c (verify_changes): Verify that changes[i].old is non-zero before applying REG_P.

        * recog.c (verify_changes): Verify that changes[i].old is non-zero
        before applying REG_P.

From-SVN: r202107

gcc/ChangeLog

+2013-08-30  Joern Rennecke  <joern.rennecke@embecosm.com>
+
+	* recog.c (verify_changes): Verify that changes[i].old is non-zero
+	before applying REG_P.
+
 2013-08-30  Jakub Jelinek  <jakub@redhat.com>
 
 	PR tree-optimization/58277

gcc/recog.c

@@ -397,7 +397,10 @@ verify_changes (int num)
 					     MEM_ADDR_SPACE (object)))
 	    break;
 	}
-      else if (REG_P (changes[i].old)
+      else if (/* changes[i].old might be zero, e.g. when putting a
+	       REG_FRAME_RELATED_EXPR into a previously empty list.  */
+	       changes[i].old
+	       && REG_P (changes[i].old)
 	       && asm_noperands (PATTERN (object)) > 0
 	       && REG_EXPR (changes[i].old) != NULL_TREE
 	       && DECL_ASSEMBLER_NAME_SET_P (REG_EXPR (changes[i].old))