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tree-ssa-loop-ivopts.c (ivopts_estimate_reg_pressure): New reg_pressure model function.

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* tree-ssa-loop-ivopts.c (ivopts_estimate_reg_pressure): New
	reg_pressure model function.
	(ivopts_global_cost_for_size): Delete.
	(determine_set_costs, iv_ca_recount_cost): Call new model function
	ivopts_estimate_reg_pressure.

From-SVN: r248954
This commit is contained in:
Bin Cheng 2017-06-07 10:45:03 +00:00 committed by Bin Cheng
parent cb9ac430cb
commit c18101f5d1
2 changed files with 47 additions and 10 deletions
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8
gcc/ChangeLog
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@ -1,3 +1,11 @@
2017-06-07 Bin Cheng <bin.cheng@arm.com>
* tree-ssa-loop-ivopts.c (ivopts_estimate_reg_pressure): New
reg_pressure model function.
(ivopts_global_cost_for_size): Delete.
(determine_set_costs, iv_ca_recount_cost): Call new model function
ivopts_estimate_reg_pressure.
2017-06-07 Tamar Christina <tamar.christina@arm.com>
* config/aarch64/aarch64.c (aarch64_rtx_costs): Make sdiv more expensive than udiv.

49
gcc/tree-ssa-loop-ivopts.c
View File

@ -5531,17 +5531,46 @@ determine_iv_costs (struct ivopts_data *data)
fprintf (dump_file, "\n");
}
/* Calculates cost for having N_REGS registers. This number includes
induction variables, invariant variables and invariant expressions. */
/* Estimate register pressure for loop having N_INVS invariants and N_CANDS
induction variables. Note N_INVS includes both invariant variables and
invariant expressions. */
static unsigned
ivopts_global_cost_for_size (struct ivopts_data *data, unsigned n_regs)
ivopts_estimate_reg_pressure (struct ivopts_data *data, unsigned n_invs,
unsigned n_cands)
{
unsigned cost = estimate_reg_pressure_cost (n_regs,
data->regs_used, data->speed,
data->body_includes_call);
/* Add n_regs to the cost, so that we prefer eliminating ivs if possible. */
return n_regs + cost;
unsigned cost;
unsigned n_old = data->regs_used, n_new = n_invs + n_cands;
unsigned regs_needed = n_new + n_old, available_regs = target_avail_regs;
bool speed = data->speed;
/* If there is a call in the loop body, the call-clobbered registers
are not available for loop invariants. */
if (data->body_includes_call)
available_regs = available_regs - target_clobbered_regs;
/* If we have enough registers. */
if (regs_needed + target_res_regs < available_regs)
cost = n_new;
/* If close to running out of registers, try to preserve them. */
else if (regs_needed <= available_regs)
cost = target_reg_cost [speed] * regs_needed;
/* If we run out of available registers but the number of candidates
does not, we penalize extra registers using target_spill_cost. */
else if (n_cands <= available_regs)
cost = target_reg_cost [speed] * available_regs
+ target_spill_cost [speed] * (regs_needed - available_regs);
/* If the number of candidates runs out available registers, we penalize
extra candidate registers using target_spill_cost * 2. Because it is
more expensive to spill induction variable than invariant. */
else
cost = target_reg_cost [speed] * available_regs
+ target_spill_cost [speed] * (n_cands - available_regs) * 2
+ target_spill_cost [speed] * (regs_needed - n_cands);
/* Finally, add the number of candidates, so that we prefer eliminating
induction variables if possible. */
return cost + n_cands;
}
/* For each size of the induction variable set determine the penalty. */
@ -5602,7 +5631,7 @@ determine_set_costs (struct ivopts_data *data)
fprintf (dump_file, " ivs\tcost\n");
for (j = 0; j <= 2 * target_avail_regs; j++)
fprintf (dump_file, " %d\t%d\n", j,
ivopts_global_cost_for_size (data, j));
ivopts_estimate_reg_pressure (data, 0, j));
fprintf (dump_file, "\n");
}
}
@ -5661,7 +5690,7 @@ iv_ca_recount_cost (struct ivopts_data *data, struct iv_ca *ivs)
comp_cost cost = ivs->cand_use_cost;
cost += ivs->cand_cost;
cost += ivopts_global_cost_for_size (data, ivs->n_invs + ivs->n_cands);
cost += ivopts_estimate_reg_pressure (data, ivs->n_invs, ivs->n_cands);
ivs->cost = cost;
}