From 2991622862dd934e464f542e9e58270bf0088544 Mon Sep 17 00:00:00 2001
From: marxin <mliska@suse.cz>
Date: Tue, 17 May 2016 15:22:43 +0200
Subject: [PATCH 1/5] Add profiling support for IVOPTS
gcc/ChangeLog:
2016-05-17 Martin Liska <mliska@suse.cz>
* tree-ssa-loop-ivopts.c (get_computation_cost_at): Scale
computed costs by frequency of BB they belong to.
(get_scaled_computation_cost_at): New function.
---
gcc/tree-ssa-loop-ivopts.c | 62 ++++++++++++++++++++++++++++++++++------------
1 file changed, 46 insertions(+), 16 deletions(-)
@@ -4794,7 +4794,33 @@ get_loop_invariant_expr (struct ivopts_data *data, tree ubase,
return record_inv_expr (data, expr);
}
+/* Scale (multiply) the computed COST (except scratch part that should be
+ hoisted out a loop) by header->frequency / AT->frequency,
+ which makes expected cost more accurate. */
+static comp_cost
+get_scaled_computation_cost_at (ivopts_data *data, gimple *at, iv_cand *cand,
+ comp_cost cost)
+{
+ int loop_freq = data->current_loop->header->frequency;
+ int bb_freq = at->bb->frequency;
+ if (loop_freq != 0)
+ {
+ gcc_assert (cost.scratch <= cost.cost);
+ int scaled_cost
+ = cost.scratch + (cost.cost - cost.scratch) * bb_freq / loop_freq;
+
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ fprintf (dump_file, "Scaling iv_use based on cand %d "
+ "by %2.2f: %d (scratch: %d) -> %d (%d/%d)\n",
+ cand->id, 1.0f * bb_freq / loop_freq, cost.cost,
+ cost.scratch, scaled_cost, bb_freq, loop_freq);
+
+ cost.cost = scaled_cost;
+ }
+
+ return cost;
+}
/* Determines the cost of the computation by that USE is expressed
from induction variable CAND. If ADDRESS_P is true, we just need
@@ -4982,18 +5008,21 @@ get_computation_cost_at (struct ivopts_data *data,
(symbol/var1/const parts may be omitted). If we are looking for an
address, find the cost of addressing this. */
if (address_p)
- return cost + get_address_cost (symbol_present, var_present,
- offset, ratio, cstepi,
- mem_mode,
- TYPE_ADDR_SPACE (TREE_TYPE (utype)),
- speed, stmt_is_after_inc, can_autoinc);
+ {
+ cost += get_address_cost (symbol_present, var_present,
+ offset, ratio, cstepi,
+ mem_mode,
+ TYPE_ADDR_SPACE (TREE_TYPE (utype)),
+ speed, stmt_is_after_inc, can_autoinc);
+ return get_scaled_computation_cost_at (data, at, cand, cost);
+ }
/* Otherwise estimate the costs for computing the expression. */
if (!symbol_present && !var_present && !offset)
{
if (ratio != 1)
cost += mult_by_coeff_cost (ratio, TYPE_MODE (ctype), speed);
- return cost;
+ return get_scaled_computation_cost_at (data, at, cand, cost);
}
/* Symbol + offset should be compile-time computable so consider that they
@@ -5012,24 +5041,25 @@ get_computation_cost_at (struct ivopts_data *data,
aratio = ratio > 0 ? ratio : -ratio;
if (aratio != 1)
cost += mult_by_coeff_cost (aratio, TYPE_MODE (ctype), speed);
- return cost;
+
+ return get_scaled_computation_cost_at (data, at, cand, cost);
fallback:
if (can_autoinc)
*can_autoinc = false;
- {
- /* Just get the expression, expand it and measure the cost. */
- tree comp = get_computation_at (data->current_loop, use, cand, at);
+ /* Just get the expression, expand it and measure the cost. */
+ tree comp = get_computation_at (data->current_loop, use, cand, at);
- if (!comp)
- return infinite_cost;
+ if (!comp)
+ return infinite_cost;
+
+ if (address_p)
+ comp = build_simple_mem_ref (comp);
- if (address_p)
- comp = build_simple_mem_ref (comp);
+ cost = comp_cost (computation_cost (comp, speed), 0);
- return comp_cost (computation_cost (comp, speed), 0);
- }
+ return get_scaled_computation_cost_at (data, at, cand, cost);
}
/* Determines the cost of the computation by that USE is expressed
--
2.8.3