unroll.c (loop_iterations): If we cannot prove iteration variable is set once in…

unroll.c (loop_iterations): If we cannot prove iteration variable is set once in each iteration, punt.

	* unroll.c (loop_iterations): If we cannot prove iteration variable
	is set once in each iteration, punt.

From-SVN: r38996

gcc/ChangeLog

+2001-01-13  Jakub Jelinek  <jakub@redhat.com>
+
+	* unroll.c (loop_iterations): If we cannot prove iteration variable
+	is set once in each iteration, punt.
+
 Sun Jan 14 00:23:15 2001  Denis Chertykov  <denisc@overta.ru>
 
 	* config/avr/avr.md ("strlenhi"): Remove clobber of input address.

gcc/unroll.c

@@ -3577,6 +3577,13 @@ loop_iterations (loop)
       /* Grab initial value, only useful if it is a constant.  */
       bl = REG_IV_CLASS (ivs, REGNO (iteration_var));
       initial_value = bl->initial_value;
+      if (!bl->biv->always_executed || bl->biv->maybe_multiple)
+	{
+	  if (loop_dump_stream)
+	    fprintf (loop_dump_stream,
+		     "Loop iterations: Basic induction var not set once in each iteration.\n");
+	  return 0;
+	}
 
       increment = biv_total_increment (bl);
     }
@@ -3589,6 +3596,14 @@ loop_iterations (loop)
       if (REGNO (v->src_reg) >= ivs->n_regs)
 	abort ();
 
+      if (!v->always_executed || v->maybe_multiple)
+	{
+	  if (loop_dump_stream)
+	    fprintf (loop_dump_stream,
+		     "Loop iterations: General induction var not set once in each iteration.\n");
+	  return 0;
+	}
+
       bl = REG_IV_CLASS (ivs, REGNO (v->src_reg));
 
       /* Increment value is mult_val times the increment value of the biv.  */