bfin.md (doloop_end): Fail for loops that can iterate 2^32-1 or more times unless...

	* config/bfin/bfin.md (doloop_end): Fail for loops that can iterate
	2^32-1 or more times unless flag_unsafe_loop_optimizations.

From-SVN: r122262

gcc/ChangeLog

+2007-02-23  Bernd Schmidt  <bernd.schmidt@analog.com>
+
+	* config/bfin/bfin.md (doloop_end): Fail for loops that can iterate
+	2^32-1 or more times unless flag_unsafe_loop_optimizations.
+
 2007-02-23  Kaveh R. Ghazi  <ghazi@caip.rutgers.edu>
 
 	* builtins.c (fold_builtin_logb, fold_builtin_significand): New.

gcc/config/bfin/bfin.md

@@ -1639,7 +1639,16 @@
 	      (unspec [(const_int 0)] UNSPEC_LSETUP_END)
 	      (clobber (match_scratch:SI 5 ""))])]
   ""
-  {bfin_hardware_loop ();})
+{
+  /* Due to limitations in the hardware (an initial loop count of 0
+     does not loop 2^32 times) we must avoid to generate a hardware
+     loops when we cannot rule out this case.  */
+
+  if (!flag_unsafe_loop_optimizations
+      && (unsigned HOST_WIDE_INT) INTVAL (operands[2]) >= 0xFFFFFFFF)
+    FAIL;
+  bfin_hardware_loop ();
+})
 
 (define_insn "loop_end"
   [(set (pc)