loop.c (strength_reduce): Call check_ext_dependant_givs.

        * loop.c (strength_reduce): Call check_ext_dependant_givs.
        Properly extend the biv initial value for the giv.
        (record_biv): Zero ext_dependant.
        (record_giv): New argument ext_val.  Update all callers.
        (general_induction_var): Likewise.
        (consec_sets_giv): Likewise.
        (simplify_giv_expr): Likewise.  Fill in ext_val if we find
        a sign-extend, zero-extend, or truncate.
        (combine_givs_p): Make sure modes are compatible.
        (check_ext_dependant_givs): New.
        (extend_value_for_giv): New.
        * loop.h (struct induction): Add ext_dependant.
        * unroll.c (iteration_info): Extend the biv initial value for the giv.
        (find_splittable_givs): Likewise.
        (final_giv_value): Likewise.

From-SVN: r36250

gcc/ChangeLog

+2000-09-07  Richard Henderson  <rth@cygnus.com>
+
+	* loop.c (strength_reduce): Call check_ext_dependant_givs.
+	Properly extend the biv initial value for the giv.
+	(record_biv): Zero ext_dependant.
+	(record_giv): New argument ext_val.  Update all callers.
+	(general_induction_var): Likewise.
+	(consec_sets_giv): Likewise.
+	(simplify_giv_expr): Likewise.  Fill in ext_val if we find
+	a sign-extend, zero-extend, or truncate.
+	(combine_givs_p): Make sure modes are compatible.
+	(check_ext_dependant_givs): New.
+	(extend_value_for_giv): New.
+	* loop.h (struct induction): Add ext_dependant.
+	* unroll.c (iteration_info): Extend the biv initial value for the giv.
+	(find_splittable_givs): Likewise.
+	(final_giv_value): Likewise.
+
 2000-09-07  Zack Weinberg  <zack@wolery.cumb.org>
 
 	* c-pragma.h: Define HANDLE_GENERIC_PRAGMAS if
@@ -64,9 +82,9 @@ Thu 07-Sep-2000 21:29:00 BST  Neil Booth  <NeilB@earthling.net>
 
 2000-09-07  Catherine Moore  <clm@redhat.com>
 
-        * unroll.c (unroll_loop): Check for unconditional jumps
-        to loop continuation.  Delete if n_iterations is 1.
-        (ujump_to_loop_cont): New routine.
+	* unroll.c (unroll_loop): Check for unconditional jumps
+	to loop continuation.  Delete if n_iterations is 1.
+	(ujump_to_loop_cont): New routine.
 
 2000-09-07  Bernd Schmidt  <bernds@redhat.co.uk>
 
@@ -151,7 +169,7 @@ Thu 07-Sep-2000 21:29:00 BST  Neil Booth  <NeilB@earthling.net>
 
 2000-09-06 Herman A.J. ten Brugge <Haj.Ten.Brugge@net.HCC.nl>
 
-        * flow.c (insn_dead_p): Detect dead memory stores with auto increments.
+	* flow.c (insn_dead_p): Detect dead memory stores with auto increments.
 
 2000-09-06  Kazu Hirata  <kazu@hxi.com>
 
@@ -159,7 +177,7 @@ Thu 07-Sep-2000 21:29:00 BST  Neil Booth  <NeilB@earthling.net>
 
 2000-09-06  Graham Stott  <grahams@cygnus.co.uk>
 
-        * config/i386/i386.h (ADDRESS_COST): Fix typo.
+	* config/i386/i386.h (ADDRESS_COST): Fix typo.
 
 2000-09-06  Zack Weinberg  <zack@wolery.cumb.org>
 

gcc/loop.h

@@ -115,6 +115,8 @@ struct induction
 				   subtracted from add_val when this giv
 				   derives another.  This occurs when the
 				   giv spans a biv update by incrementation. */
+  rtx ext_dependant;		/* If nonzero, is a sign or zero extension
+				   if a biv on which this giv is dependant.  */
   struct induction *next_iv;	/* For givs, links together all givs that are
 				   based on the same biv.  For bivs, links
 				   together all biv entries that refer to the
@@ -238,6 +240,7 @@ int loop_invariant_p PARAMS ((const struct loop *, rtx));
 rtx get_condition_for_loop PARAMS ((const struct loop *, rtx));
 void emit_iv_add_mult PARAMS ((rtx, rtx, rtx, rtx, rtx));
 rtx express_from PARAMS ((struct induction *, struct induction *));
+rtx extend_value_for_giv PARAMS ((struct induction *, rtx));
 
 void unroll_loop PARAMS ((struct loop *, int, rtx, int));
 rtx biv_total_increment PARAMS ((struct iv_class *));
@@ -251,7 +254,7 @@ void emit_unrolled_add PARAMS ((rtx, rtx, rtx));
 int back_branch_in_range_p PARAMS ((const struct loop *, rtx));
 
 int loop_insn_first_p PARAMS ((rtx, rtx));
-typedef rtx (*loop_insn_callback ) PARAMS ((struct loop *, rtx, int, int));
+typedef rtx (*loop_insn_callback) PARAMS ((struct loop *, rtx, int, int));
 void for_each_insn_in_loop PARAMS ((struct loop *, loop_insn_callback));
 
 /* Forward declarations for non-static functions declared in doloop.c.  */

gcc/unroll.c

@@ -2495,6 +2495,7 @@ iteration_info (loop, iteration_var, initial_value, increment)
     {
       HOST_WIDE_INT offset = 0;
       struct induction *v = REG_IV_INFO (REGNO (iteration_var));
+      rtx biv_initial_value;
 
       if (REGNO (v->src_reg) >= max_reg_before_loop)
 	abort ();
@@ -2527,11 +2528,13 @@ iteration_info (loop, iteration_var, initial_value, increment)
 	fprintf (loop_dump_stream,
 		 "Loop unrolling: Giv iterator, initial value bias %ld.\n",
 		 (long) offset);
+
       /* Initial value is mult_val times the biv's initial value plus
 	 add_val.  Only useful if it is a constant.  */
+      biv_initial_value = extend_value_for_giv (v, bl->initial_value);
       *initial_value
 	= fold_rtx_mult_add (v->mult_val,
-			     plus_constant (bl->initial_value, offset),
+			     plus_constant (biv_initial_value, offset),
 			     v->add_val, v->mode);
     }
   else
@@ -2895,6 +2898,7 @@ find_splittable_givs (loop, bl, unroll_type, increment, unroll_number)
 				loop->start);
 	      biv_initial_value = tem;
 	    }
+	  biv_initial_value = extend_value_for_giv (v, biv_initial_value);
 	  value = fold_rtx_mult_add (v->mult_val, biv_initial_value,
 				     v->add_val, v->mode);
 	}
@@ -3456,10 +3460,11 @@ final_giv_value (loop, v)
 	  insert_before = NEXT_INSN (loop_end);
 
 	  /* Put the final biv value in tem.  */
-	  tem = gen_reg_rtx (bl->biv->mode);
+	  tem = gen_reg_rtx (v->mode);
 	  record_base_value (REGNO (tem), bl->biv->add_val, 0);
 	  emit_iv_add_mult (increment, GEN_INT (n_iterations),
-			    bl->initial_value, tem, insert_before);
+			    extend_value_for_giv (v, bl->initial_value),
+			    tem, insert_before);
 
 	  /* Subtract off extra increments as we find them.  */
 	  for (insn = NEXT_INSN (v->insn); insn != loop_end;