Fix hpux loop unrolling bug reported by Tim Prince.

	* loop.h (struct induction): Clarify comment for unrolled field.
	* unroll.c (find_splittable_givs): Move set of unrolled field
	after address validity check.

From-SVN: r20598

gcc/ChangeLog

+1998-06-19  Jim Wilson  <wilson@cygnus.com>
+
+	* loop.h (struct induction): Clarify comment for unrolled field.
+	* unroll.c (find_splittable_givs): Move set of unrolled field
+	after address validity check.
+
 Fri Jun 19 18:38:04 1998  Michael Meissner  <meissner@cygnus.com>
 
 	* config/fp-bit.c (INLINE): Only define if not already defined.

gcc/loop.h

@@ -92,8 +92,8 @@ struct induction
 				   would probably lose. */
   unsigned auto_inc_opt : 1;	/* 1 if this giv had its increment output next
 				   to it to try to form an auto-inc address. */
-  unsigned unrolled : 1;	/* 1 if new register has been allocated in
-				   unrolled loop.  */
+  unsigned unrolled : 1;	/* 1 if new register has been allocated and
+				   initialized in unrolled loop.  */
   unsigned shared : 1;
   int lifetime;			/* Length of life of this giv */
   int times_used;		/* # times this giv is used. */

gcc/unroll.c

@@ -2907,7 +2907,6 @@ find_splittable_givs (bl, unroll_type, loop_start, loop_end, increment,
 
 		  rtx tem = gen_reg_rtx (v->mode);
 		  record_base_value (REGNO (tem), v->add_val, 0);
-		  v->unrolled = 1;
 
 		  /* If the address giv has a constant in its new_reg value,
 		     then this constant can be pulled out and put in value,
@@ -2960,6 +2959,10 @@ find_splittable_givs (bl, unroll_type, loop_start, loop_end, increment,
 		      continue;
 		    }
 		  
+		  /* We set this after the address check, to guarantee that
+		     the register will be initialized.  */
+		  v->unrolled = 1;
+
 		  /* To initialize the new register, just move the value of
 		     new_reg into it.  This is not guaranteed to give a valid
 		     instruction on machines with complex addressing modes.