(strength_reduce): If HAVE_cc0 defined, disable auto_inc_opt

if it would put an insn between a cc0 setter/user pair.

From-SVN: r12176

gcc/loop.c

@@ -3937,6 +3937,15 @@ strength_reduce (scan_start, end, loop_top, insn_count,
 		  else
 		    auto_inc_opt = 1;
 
+#ifdef HAVE_cc0
+		  /* We can't put an insn immediately after one setting
+		     cc0, or immediately before one using cc0.  */
+		  if ((auto_inc_opt == 1 && sets_cc0_p (PATTERN (v->insn)))
+		      || (auto_inc_opt == -1
+			  && sets_cc0_p (PATTERN (prev_nonnote_insn (v->insn)))))
+		    auto_inc_opt = 0;
+#endif
+
 		  if (auto_inc_opt)
 		    v->auto_inc_opt = 1;
 		}