unroll.c (find_splittable_givs): Only share if two givs have the same add and multiply values.

        * unroll.c (find_splittable_givs): Only share if two givs have the
        same add and multiply values.
Fixes some testsuite failures on the x86.

From-SVN: r14908

gcc/ChangeLog

+Sat Aug 23 18:19:40 1997  John F. Carr  <jfc@mit.edu>
+
+	* unroll.c (find_splittable_givs): Only share if two givs have the
+	same add and multiply values.
+
 Sat Aug 23 14:36:27 1997  Jim Wilson  <wilson@cygnus.com>
 
 	* m68k/next.h (GO_IF_INDEXABLE_BASE): Fix typo in undef.

gcc/unroll.c

@@ -2849,7 +2849,14 @@ find_splittable_givs (bl, unroll_type, loop_start, loop_end, increment,
 	      else if (unroll_type != UNROLL_COMPLETELY
 		       && v->giv_type == DEST_ADDR
 		       && v->same && v->same->giv_type == DEST_ADDR
-		       && v->same->unrolled)
+		       && v->same->unrolled
+		       /* combine_givs_p may return true for some cases
+			  where the add and mult values are not equal.
+			  To share a register here, the values must be
+			  equal.  */
+		       && rtx_equal_p (v->same->mult_val, v->mult_val)
+		       && rtx_equal_p (v->same->add_val, v->add_val))
+
 		{
 		  v->dest_reg = v->same->dest_reg;
 		  v->shared = 1;