tree-ssa-loop-niter.c (record_estimate): Add "upper" argument.

	* tree-ssa-loop-niter.c (record_estimate): Add "upper" argument.
	Update constant estimates of number of iterations.
	(record_nonwrapping_iv): Add "upper" argument.  "data_size_bounds_p"
	argument renamed to "realistic".
	(compute_estimated_nb_iterations): Removed.
	(record_niter_bound): New function.
	(idx_infer_loop_bounds): For possible but unlikely tail arrays,
	call record_nonwrapping_iv with upper = false.
	(infer_loop_bounds_from_signedness): Pass upper argument to
	record_nonwrapping_iv.
	(estimate_numbers_of_iterations_loop): Do not call
	compute_estimated_nb_iterations.  Record estimate based on profile
	information.  Initialize the constant estimates of number of
	iterations.
	* tree-data-ref.c (estimated_loop_iterations): Return the recorded
	estimates.
	* tree-ssa-loop-prefetch.c (loop_prefetch_arrays): Add dump when
	number of iterations is too small.
	* cfgloop.h (struct nb_iter_bound): Remove "realistic" field.
	(EST_NOT_AVAILABLE): Removed.
	(struct loop): Replace estimated_nb_iterations by any_upper_bound,
	nb_iterations_upper_bound, any_estimate and nb_iterations_estimate
	fields.

	* gcc.dg/tree-ssa/prefetch-5.c: New test.

From-SVN: r122969

1 files changed, 11 insertions, 21 deletions

diff --git a/gcc/tree-data-ref.c b/gcc/tree-data-ref.c
index d59278c..01bb71b 100644
--- a/gcc/tree-data-ref.c
+++ b/gcc/tree-data-ref.c
@@ -2556,33 +2556,23 @@ static bool
 estimated_loop_iterations (struct loop *loop, bool conservative,
 			   double_int *nit)
 {
-  tree numiter = number_of_exit_cond_executions (loop);
-
-  /* If we have an exact value, use it.  */
-  if (TREE_CODE (numiter) == INTEGER_CST)
+  estimate_numbers_of_iterations_loop (loop);
+  if (conservative)
     {
-      *nit = tree_to_double_int (numiter);
-      return true;
-    }
+      if (!loop->any_upper_bound)
+	return false;
 
-  /* If we have a measured profile and we do not ask for a conservative bound,
-     use it.  */
-  if (!conservative && loop->header->count != 0)
-    {
-      *nit = uhwi_to_double_int (expected_loop_iterations (loop) + 1);
-      return true;
+      *nit = loop->nb_iterations_upper_bound;
     }
-
-  /* Finally, try using a reliable estimate on number of iterations according
-     to the size of the accessed data, if available.  */
-  estimate_numbers_of_iterations_loop (loop);
-  if (loop->estimate_state == EST_AVAILABLE)
+  else
     {
-      *nit = loop->estimated_nb_iterations;
-      return true;
+      if (!loop->any_estimate)
+	return false;
+
+      *nit = loop->nb_iterations_estimate;
     }
 
-  return false;
+  return true;
 }
 
 /* Similar to estimated_loop_iterations, but returns the estimate only