[PATCH GCC8][04/33]Single interface finding invariant variables

[Bin Cheng]

Hi,
This patch refactors interface finding invariant variables.  Now customers
only need to call find_inv_vars, rather than set global variable fd_ivopts_data
then call walk_tree.
Is it OK?

Thanks,
bin

2017-04-11  Bin Cheng  <bin.ch...@arm.com>

        * tree-ssa-loop-ivopts.c (struct walk_tree_data): New.
        (find_inv_vars_cb): New.
        (find_depends): Renamed to ...
        (find_inv_vars): ... this.
        (add_candidate_1, force_var_cost): Call find_inv_vars.
        (split_address_cost, determine_group_iv_cost_cond): Ditto.
From d3d0df5f794f83ab03edced03e268ff635b95ec9 Mon Sep 17 00:00:00 2001
From: Bin Cheng <binch...@e108451-lin.cambridge.arm.com>
Date: Tue, 28 Feb 2017 14:12:37 +0000
Subject: [PATCH 04/33] refactor-find-inv-variables-20170220.txt

---
 gcc/tree-ssa-loop-ivopts.c | 66 ++++++++++++++++++++++++++++------------------
 1 file changed, 40 insertions(+), 26 deletions(-)

diff --git a/gcc/tree-ssa-loop-ivopts.c b/gcc/tree-ssa-loop-ivopts.c
index f9914e0..3a5b1b9 100644
--- a/gcc/tree-ssa-loop-ivopts.c
+++ b/gcc/tree-ssa-loop-ivopts.c
@@ -2896,30 +2896,53 @@ generic_type_for (tree type)
   return unsigned_type_for (type);
 }
 
-/* Records invariants in *EXPR_P.  Callback for walk_tree.  DATA contains
-   the bitmap to that we should store it.  */
+/* Private data for walk_tree.  */
+
+struct walk_tree_data
+{
+  bitmap *inv_vars;
+  struct ivopts_data *idata;
+};
+
+/* Callback function for walk_tree, it records invariants and symbol
+   reference in *EXPR_P.  DATA is the structure storing result info.  */
 
-static struct ivopts_data *fd_ivopts_data;
 static tree
-find_depends (tree *expr_p, int *ws ATTRIBUTE_UNUSED, void *data)
+find_inv_vars_cb (tree *expr_p, int *ws ATTRIBUTE_UNUSED, void *data)
 {
-  bitmap *inv_vars = (bitmap *) data;
+  struct walk_tree_data *wdata = (struct walk_tree_data*) data;
   struct version_info *info;
 
   if (TREE_CODE (*expr_p) != SSA_NAME)
     return NULL_TREE;
-  info = name_info (fd_ivopts_data, *expr_p);
 
+  info = name_info (wdata->idata, *expr_p);
   if (!info->inv_id || info->has_nonlin_use)
     return NULL_TREE;
 
-  if (!*inv_vars)
-    *inv_vars = BITMAP_ALLOC (NULL);
-  bitmap_set_bit (*inv_vars, info->inv_id);
+  if (!*wdata->inv_vars)
+    *wdata->inv_vars = BITMAP_ALLOC (NULL);
+  bitmap_set_bit (*wdata->inv_vars, info->inv_id);
 
   return NULL_TREE;
 }
 
+/* Records invariants in *EXPR_P.  INV_VARS is the bitmap to that we should
+   store it.  */
+
+static inline void
+find_inv_vars (struct ivopts_data *data, tree *expr_p, bitmap *inv_vars)
+{
+  struct walk_tree_data wdata;
+
+  if (!inv_vars)
+    return;
+
+  wdata.idata = data;
+  wdata.inv_vars = inv_vars;
+  walk_tree (expr_p, find_inv_vars_cb, &wdata, NULL);
+}
+
 /* Adds a candidate BASE + STEP * i.  Important field is set to IMPORTANT and
    position to POS.  If USE is not NULL, the candidate is set as related to
    it.  If both BASE and STEP are NULL, we add a pseudocandidate for the
@@ -2996,10 +3019,7 @@ add_candidate_1 (struct ivopts_data *data,
       data->vcands.safe_push (cand);
 
       if (TREE_CODE (step) != INTEGER_CST)
-       {
-         fd_ivopts_data = data;
-         walk_tree (&step, find_depends, &cand->inv_vars, NULL);
-       }
+       find_inv_vars (data, &step, &cand->inv_vars);
 
       if (pos == IP_AFTER_USE || pos == IP_BEFORE_USE)
        cand->ainc_use = use;
@@ -4486,15 +4506,12 @@ force_expr_to_var_cost (tree expr, bool speed)
    invariants the computation depends on.  */
 
 static comp_cost
-force_var_cost (struct ivopts_data *data,
-               tree expr, bitmap *inv_vars)
+force_var_cost (struct ivopts_data *data, tree expr, bitmap *inv_vars)
 {
-  if (inv_vars)
-    {
-      fd_ivopts_data = data;
-      walk_tree (&expr, find_depends, inv_vars, NULL);
-    }
+  if (!expr)
+    return no_cost;
 
+  find_inv_vars (data, &expr, inv_vars);
   return force_expr_to_var_cost (expr, data->speed);
 }
 
@@ -4525,10 +4542,7 @@ split_address_cost (struct ivopts_data *data,
     {
       *symbol_present = false;
       *var_present = true;
-      fd_ivopts_data = data;
-      if (inv_vars)
-       walk_tree (&addr, find_depends, inv_vars, NULL);
-
+      find_inv_vars (data, &addr, inv_vars);
       return comp_cost (target_spill_cost[data->speed], 0);
     }
 
@@ -5624,8 +5638,8 @@ determine_group_iv_cost_cond (struct ivopts_data *data,
   express_cost = get_computation_cost (data, use, cand, false,
                                       &inv_vars_express, NULL,
                                       &inv_expr_express);
-  fd_ivopts_data = data;
-  walk_tree (&cmp_iv->base, find_depends, &inv_vars_express, NULL);
+  if (cmp_iv != NULL)
+    find_inv_vars (data, &cmp_iv->base, &inv_vars_express);
 
   /* Count the cost of the original bound as well.  */
   bound_cost = force_var_cost (data, *bound_cst, NULL);
-- 
1.9.1