Remove creation of invalid subreg. PR 7705, 7339, 7720.

From-SVN: r57315

gcc/ChangeLog

+2002-09-19  Dale Johannesen <dalej@apple.com>
+	* combine.c (make_extraction): Don't create
+	invalid subreg.
+
 2002-09-19  Ulrich Weigand  <uweigand@de.ibm.com>
 
 	* config/s390/s390.c (addr_generation_dependency_p): Handle SUBREG 

gcc/combine.c

@@ -6124,6 +6124,11 @@ make_extraction (mode, inner, pos, pos_rtx, len,
 		final_word += (GET_MODE_SIZE (inner_mode)
 			       - GET_MODE_SIZE (tmode)) % UNITS_PER_WORD;
 
+	      /* Avoid creating invalid subregs, for example when
+		 simplifying (x>>32)&255. */
+	      if (final_word >= GET_MODE_SIZE (inner_mode))
+		return NULL_RTX;
+
 	      new = gen_rtx_SUBREG (tmode, inner, final_word);
 	    }
 	  else