[PATCH GCC8][17/33]Treat complex cand step as invriant expression

[Bin Cheng]

Hi,
We generally need to compute cand step in loop preheader and use it in loop 
body.
Unless it's an SSA_NAME of constant integer, an invariant expression is needed.

Thanks,
bin

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

        * tree-ssa-loop-ivopts.c (struct iv_cand): New field inv_exprs.
        (dump_cand): Support iv_cand.inv_exprs.
        (add_candidate_1): Record invariant exprs in iv_cand.inv_exprs
        for candidates.
        (iv_ca_set_no_cp, iv_ca_set_cp, free_loop_data): Support
        iv_cand.inv_exprs.
From 06806d09f557854a5987b83a044a5eb5433cda60 Mon Sep 17 00:00:00 2001
From: Bin Cheng <binch...@e108451-lin.cambridge.arm.com>
Date: Wed, 1 Mar 2017 14:50:11 +0000
Subject: [PATCH 17/33] treat-cand_step-as-inv_expr-20170225.txt

---
 gcc/tree-ssa-loop-ivopts.c | 28 +++++++++++++++++++++++++++-
 1 file changed, 27 insertions(+), 1 deletion(-)

diff --git a/gcc/tree-ssa-loop-ivopts.c b/gcc/tree-ssa-loop-ivopts.c
index c3e9bce..2c6fa76 100644
--- a/gcc/tree-ssa-loop-ivopts.c
+++ b/gcc/tree-ssa-loop-ivopts.c
@@ -421,6 +421,7 @@ struct iv_cand
                              where it is incremented.  */
   bitmap inv_vars;     /* The list of invariants that are used in step of the
                           biv.  */
+  bitmap inv_exprs;    /* Hanlde step as inv expr if it's not simple.  */
   struct iv *orig_iv;  /* The original iv if this cand is added from biv with
                           smaller type.  */
 };
@@ -790,6 +791,11 @@ dump_cand (FILE *file, struct iv_cand *cand)
       fprintf (file, "  Depend on inv.vars: ");
       dump_bitmap (file, cand->inv_vars);
     }
+  if (cand->inv_exprs)
+    {
+      fprintf (file, "  Depend on inv.exprs: ");
+      dump_bitmap (file, cand->inv_exprs);
+    }
 
   if (cand->var_before)
     {
@@ -3032,7 +3038,23 @@ add_candidate_1 (struct ivopts_data *data,
       data->vcands.safe_push (cand);
 
       if (TREE_CODE (step) != INTEGER_CST)
-       find_inv_vars (data, &step, &cand->inv_vars);
+       {
+         find_inv_vars (data, &step, &cand->inv_vars);
+
+         iv_inv_expr_ent *inv_expr = get_loop_invariant_expr (data, step);
+         /* Share bitmap between inv_vars and inv_exprs for cand.  */
+         if (inv_expr != NULL)
+           {
+             cand->inv_exprs = cand->inv_vars;
+             cand->inv_vars = NULL;
+             if (cand->inv_exprs)
+               bitmap_clear (cand->inv_exprs);
+             else
+               cand->inv_exprs = BITMAP_ALLOC (NULL);
+
+             bitmap_set_bit (cand->inv_exprs, inv_expr->id);
+           }
+       }
 
       if (pos == IP_AFTER_USE || pos == IP_BEFORE_USE)
        cand->ainc_use = use;
@@ -5606,6 +5628,7 @@ iv_ca_set_no_cp (struct ivopts_data *data, struct iv_ca 
*ivs,
       ivs->n_cands--;
       ivs->cand_cost -= cp->cand->cost;
       iv_ca_set_remove_invs (ivs, cp->cand->inv_vars, ivs->n_inv_var_uses);
+      iv_ca_set_remove_invs (ivs, cp->cand->inv_exprs, ivs->n_inv_expr_uses);
     }
 
   ivs->cand_use_cost -= cp->cost;
@@ -5662,6 +5685,7 @@ iv_ca_set_cp (struct ivopts_data *data, struct iv_ca *ivs,
          ivs->n_cands++;
          ivs->cand_cost += cp->cand->cost;
          iv_ca_set_add_invs (ivs, cp->cand->inv_vars, ivs->n_inv_var_uses);
+         iv_ca_set_add_invs (ivs, cp->cand->inv_exprs, ivs->n_inv_expr_uses);
        }
 
       ivs->cand_use_cost += cp->cost;
@@ -7143,6 +7167,8 @@ free_loop_data (struct ivopts_data *data)
 
       if (cand->inv_vars)
        BITMAP_FREE (cand->inv_vars);
+      if (cand->inv_exprs)
+       BITMAP_FREE (cand->inv_exprs);
       free (cand);
     }
   data->vcands.truncate (0);
-- 
1.9.1