PR c++/15463

	* loop-iv.c (iv_number_of_iterations):  Use trunc_int_for_mode on
	result of inverse.

	PR rtl-optimization/15274
	* loop-iv.c (determine_max_iter, shorten_into_mode,
	iv_number_of_iterations): Handle constants correctly.
	* rtl.h (get_mode_bounds): Declaration changed.
	* stor-layout.c (get_mode_bounds): Return a constant suitable for
	the target mode.

	PR rtl-optimization/14692
	* loop-unswitch.c (may_unswitch_on): Try folding the result.
	(unswitch_single_loop): Work correctly when may_unswitch_on
	returns a folded constant.

	* loop-iv.c (implies_p): Handle A < B ==> A + 1 <= B.
	* simplify-rtx.c (simplify_const_relational_operation): Optimize
	comparisons with mode bounds.

	* function.c (struct temp_slot): Add new field prev.
	(free_after_compilation, init_temp_slots): Free new fields.
	(cut_slot_from_list, insert_slot_to_list,
	temp_slots_at_level, max_slot_level, move_slot_to_level,
	make_slot_available): New functions.
	(assign_stack_temp_for_type, combine_temp_slots,
	find_temp_slot_from_address, preserve_temp_slots,
	preserve_rtl_expr_result, free_temp_slots,
	free_temps_for_rtl_expr, pop_temp_slots): Work with
	the new structure of lists.
	(mark_all_temps_used): Removed.
	* function.h (struct function): Field x_temp_slots
	replaced by x_used_temp_slots and x_avail_temp_slots.
	(temp_slots): Replaced by ...
	(used_temp_slots, avail_temp_slots): New.
	* tree.h (mark_all_temps_used): Declaration removed.

	* loop-iv.c (mark_single_set, get_biv_step_1, iv_analyze,
	simplify_using_assignment): Take the expression out of
	the expr_list wrapper.

	* loop-iv.c (iv_number_of_iterations): Improve clasification of
	infinite loops.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@82028 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 18 insertions, 8 deletions

diff --git a/gcc/loop-unswitch.c b/gcc/loop-unswitch.c
index bedf5f8ce7c..8f1f54f0d73 100644
--- a/gcc/loop-unswitch.c
+++ b/gcc/loop-unswitch.c
@@ -174,7 +174,7 @@ unswitch_loops (struct loops *loops)
 static rtx
 may_unswitch_on (basic_block bb, struct loop *loop, rtx *cinsn)
 {
-  rtx test, at, insn, op[2];
+  rtx test, at, insn, op[2], stest;
   struct rtx_iv iv;
   unsigned i;
   enum machine_mode mode;
@@ -233,6 +233,12 @@ may_unswitch_on (basic_block bb, struct loop *loop, rtx *cinsn)
       return test;
     }
 
+  stest = simplify_gen_relational (GET_CODE (test), SImode,
+				   mode, op[0], op[1]);
+  if (stest == const0_rtx
+      || stest == const_true_rtx)
+    return stest;
+
   return canon_condition (gen_rtx_fmt_ee (GET_CODE (test), SImode,
 					  op[0], op[1]));
 }
@@ -262,7 +268,7 @@ unswitch_single_loop (struct loops *loops, struct loop *loop,
   basic_block *bbs;
   struct loop *nloop;
   unsigned i;
-  rtx cond, rcond, conds, rconds, acond, cinsn = NULL_RTX;
+  rtx cond, rcond = NULL_RTX, conds, rconds, acond, cinsn = NULL_RTX;
   int repeat;
   edge e;
 
@@ -331,13 +337,17 @@ unswitch_single_loop (struct loops *loops, struct loop *loop,
 	  return;
 	}
 
-      rcond = reversed_condition (cond);
-      if (rcond)
-	rcond = canon_condition (rcond);
+      if (cond != const0_rtx
+	  && cond != const_true_rtx)
+	{
+	  rcond = reversed_condition (cond);
+	  if (rcond)
+	    rcond = canon_condition (rcond);
 
-      /* Check whether the result can be predicted.  */
-      for (acond = cond_checked; acond; acond = XEXP (acond, 1))
-	simplify_using_condition (XEXP (acond, 0), &cond, NULL);
+	  /* Check whether the result can be predicted.  */
+	  for (acond = cond_checked; acond; acond = XEXP (acond, 1))
+	    simplify_using_condition (XEXP (acond, 0), &cond, NULL);
+	}
 
       if (cond == const_true_rtx)
 	{