Commit e4084e94 authored by Martin Bauer's avatar Martin Bauer
Browse files

Moved liveness opts to separate branch until integration is finished

parent 0cba271c
from sympy import Symbol, Dummy
from pystencils import Field, Assignment
import random
import copy
def get_usage(atoms):
reg_usage = {}
for atom in atoms:
reg_usage[atom.lhs] = 0
for atom in atoms:
for arg in atom.rhs.atoms():
if isinstance(arg, Symbol) and not isinstance(arg, Field.Access):
if arg in reg_usage:
reg_usage[arg] += 1
else:
print(str(arg) + " is unsatisfied")
return reg_usage
def get_definitions(eqs):
definitions = {}
for eq in eqs:
definitions[eq.lhs] = eq
return definitions
def get_roots(eqs):
roots = []
for eq in eqs:
if isinstance(eq.lhs, Field.Access):
roots.append(eq.lhs)
if not roots:
roots.append(eqs[-1].lhs)
return roots
def merge_field_accesses(eqs):
field_accesses = {}
for eq in eqs:
for arg in eq.rhs.atoms():
if isinstance(arg, Field.Access) and arg not in field_accesses:
field_accesses[arg] = Dummy()
for i in range(0, len(eqs)):
for f, s in field_accesses.items():
if f in eqs[i].atoms():
eqs[i] = eqs[i].subs(f, s)
for f, s in field_accesses.items():
eqs.insert(0, Assignment(s, f))
return eqs
def refuse_eqs(input_eqs, max_depth=0, max_usage=1):
eqs = copy.copy(input_eqs)
usages = get_usage(eqs)
definitions = get_definitions(eqs)
def inline_trivially_schedulable(sym, depth):
if sym not in usages or usages[sym] > max_usage or depth > max_depth:
return sym
rhs = definitions[sym].rhs
if len(rhs.args) == 0:
return rhs
return rhs.func(*[inline_trivially_schedulable(arg, depth + 1) for arg in rhs.args])
for idx, eq in enumerate(eqs):
if usages[eq.lhs] > 1 or isinstance(eq.lhs, Field.Access):
if not isinstance(eq.rhs, Symbol):
eqs[idx] = Assignment(eq.lhs,
eq.rhs.func(*[inline_trivially_schedulable(arg, 0) for arg in eq.rhs.args]))
count = 0
while (len(eqs) != count):
count = len(eqs)
usages = get_usage(eqs)
eqs = [eq for eq in eqs if usages[eq.lhs] > 0 or isinstance(eq.lhs, Field.Access)]
return eqs
def schedule_eqs(eqs, candidate_count=20):
if candidate_count == 0:
return eqs
definitions = get_definitions(eqs)
definition_atoms = {}
for sym, definition in definitions.items():
definition_atoms[sym] = list(definition.rhs.atoms(Symbol))
roots = get_roots(eqs)
initial_usages = get_usage(eqs)
level = 0
current_level_set = set([frozenset(roots)])
current_usages = {frozenset(roots): {u: 0 for u in roots}}
current_schedules = {frozenset(roots): (0, [])}
max_regs = 0
while len(current_level_set) > 0:
new_usages = dict()
new_schedules = dict()
new_level_set = set()
min_regs = min([len(current_usages[dec_set]) for dec_set in current_level_set])
max_regs = max(max_regs, min_regs)
candidates = [(dec_set, len(current_usages[dec_set])) for dec_set in current_level_set]
random.shuffle(candidates)
candidates.sort(key=lambda d: d[1])
for dec_set, regs in candidates[:candidate_count]:
for dec in dec_set:
new_dec_set = set(dec_set)
new_dec_set.remove(dec)
usage = dict(current_usages[dec_set])
usage.pop(dec)
atoms = definition_atoms[dec]
for arg in atoms:
if not isinstance(arg, Field.Access):
argu = usage.get(arg, initial_usages[arg]) - 1
if argu == 0:
new_dec_set.add(arg)
usage[arg] = argu
frozen_new_dec_set = frozenset(new_dec_set)
schedule = current_schedules[dec_set]
max_reg_count = max(len(usage), schedule[0])
if frozen_new_dec_set not in new_schedules or max_reg_count < new_schedules[frozen_new_dec_set][0]:
new_schedule = list(schedule[1])
new_schedule.append(definitions[dec])
new_schedules[frozen_new_dec_set] = (max_reg_count, new_schedule)
if len(frozen_new_dec_set) > 0:
new_level_set.add(frozen_new_dec_set)
new_usages[frozen_new_dec_set] = usage
current_schedules = new_schedules
current_usages = new_usages
current_level_set = new_level_set
level += 1
schedule = current_schedules[frozenset()]
schedule[1].reverse()
return (schedule[1])
def liveness_opt_transformation(eqs):
return refuse_eqs(merge_field_accesses(schedule_eqs(eqs, 3)), 1, 3)
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