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Commit 302f98ab authored by Taddeus Kroes's avatar Taddeus Kroes
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Improved local Copy Propagation.

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src/optimize/advanced.py
+ 106
− 39
View file @ 302f98ab
from math import log import re
from src.statement import Statement as S from src.statement import Statement as S
from src.liveness import is_reg_dead_after from src.liveness import is_reg_dead_after
...@@ -83,7 +83,7 @@ def eliminate_common_subexpressions(block): ...@@ -83,7 +83,7 @@ def eliminate_common_subexpressions(block):
# Replace all occurrences with a move statement # Replace all occurrences with a move statement
message = 'Common subexpression reference: %s %s' \ message = 'Common subexpression reference: %s %s' \
% (s.name, ', '.join(map(str, [new_reg] + s[1:]))) % (s.name, ','.join(map(str, [new_reg] + s[1:])))
for occurrence in occurrences: for occurrence in occurrences:
rd = block[occurrence][0] rd = block[occurrence][0]
...@@ -93,7 +93,7 @@ def eliminate_common_subexpressions(block): ...@@ -93,7 +93,7 @@ def eliminate_common_subexpressions(block):
# Insert the calculation before the original with the new # Insert the calculation before the original with the new
# destination address # destination address
message = 'Common subexpression: %s %s' \ message = 'Common subexpression: %s %s' \
% (s.name, ', '.join(map(str, s))) % (s.name, ','.join(map(str, s)))
block.insert(S('command', s.name, *([new_reg] + args)), \ block.insert(S('command', s.name, *([new_reg] + args)), \
index=occurrences[0], message=message) index=occurrences[0], message=message)
changed = True changed = True
...@@ -207,7 +207,7 @@ def fold_constants(block): ...@@ -207,7 +207,7 @@ def fold_constants(block):
# Replace the multiplication with two immidiate loads to the # Replace the multiplication with two immidiate loads to the
# Hi/Lo registers # Hi/Lo registers
block.replace(1, [S('command', 'li', '$hi', hi), block.replace(1, [S('command', 'li', '$hi', hi),
S('command', 'li', '$lo', li)], S('command', 'li', '$lo', lo)],
message=message) message=message)
register['$lo'], register['$hi'] = lo, hi register['$lo'], register['$hi'] = lo, hi
...@@ -276,11 +276,72 @@ def fold_constants(block): ...@@ -276,11 +276,72 @@ def fold_constants(block):
known.append((reg, 'unknown')) known.append((reg, 'unknown'))
if block.verbose and len(known): if block.verbose and len(known):
s.set_inline_comment(','.join([' %s = %s' % k for k in known])) s.set_message(','.join([' %s = %s' % k for k in known]))
return changed return changed
#def copy_propagation(block):
# """
# Unpack a move instruction, by replacing its destination
# address with its source address in the code following the move instruction.
# This way, the move statement might be a target for dead code elimination.
#
# move $regA, $regB move $regA, $regB
# ... ...
# Code not writing $regA, -> ...
# $regB ...
# ... ...
# addu $regC, $regA, ... addu $regC, $regB, ...
# """
# moves_from = []
# moves_to = []
# changed = False
#
# block.reset()
#
# while not block.end():
# s = block.read()
#
# if s.is_command('move') and s[0] not in moves_to:
# # Add this move to the lists, because it is not yet there.
# moves_from.append(s[1])
# moves_to.append(s[0])
# elif s.is_command('move') and s[0] in moves_to:
# # This move is already in the lists, so only update it
# for i in xrange(len(moves_to)):
# if moves_to[i] == s[0]:
# moves_from[i] = s[1]
# continue
# elif (len(s) == 3 or s.is_command('mlfo') or s.is_load()) \
# and (s[0] in moves_to or s[0] in moves_from):
# # One of the registers gets overwritten, so remove the data from
# # the list.
# i = 0
#
# while i < len(moves_to):
# if moves_to[i] == s[0] or moves_to[i] == s[1]:
# del moves_to[i]
# del moves_from[i]
# else:
# i += 1
# elif len(s) == 3 and (s[1] in moves_to or s[2] in moves_to):
# # Check where the result of the move is used and replace it with
# # the original variable.
# for i in xrange(len(moves_to)):
# if s[1] == moves_to[i]:
# s[1] = moves_from[i]
# continue
#
# if s[2] == moves_to[i]:
# s[2] = moves_from[i]
# continue
#
# changed = True
#
# return changed
def copy_propagation(block): def copy_propagation(block):
""" """
Unpack a move instruction, by replacing its destination Unpack a move instruction, by replacing its destination
...@@ -294,50 +355,56 @@ def copy_propagation(block): ...@@ -294,50 +355,56 @@ def copy_propagation(block):
... ... ... ...
addu $regC, $regA, ... addu $regC, $regB, ... addu $regC, $regA, ... addu $regC, $regB, ...
""" """
moves_from = []
moves_to = []
changed = False changed = False
moves = {}
block.reset() block.reset()
while not block.end(): while not block.end():
s = block.read() s = block.read()
if s.is_command('move') and s[0] not in moves_to: if not s.is_command():
# Add this move to the lists, because it is not yet there. continue
moves_from.append(s[1])
moves_to.append(s[0]) if s.name == 'move':
elif s.is_command('move') and s[0] in moves_to: # Register the move
# This move is already in the lists, so only update it reg_to, reg_from = s
for i in xrange(len(moves_to)):
if moves_to[i] == s[0]: if reg_from in moves:
moves_from[i] = s[1] if moves[reg_from] == reg_to:
continue continue
elif (len(s) == 3 or s.is_command('mlfo') or s.is_load()) \
and (s[0] in moves_to or s[0] in moves_from):
# One of the registers gets overwritten, so remove the data from
# the list.
i = 0
while i < len(moves_to):
if moves_to[i] == s[0] or moves_to[i] == s[1]:
del moves_to[i]
del moves_from[i]
else: else:
i += 1 moves[reg_to] = moves[reg_from]
elif len(s) == 3 and (s[1] in moves_to or s[2] in moves_to): elif reg_to == reg_from:
# Check where the result of the move is used and replace it with del moves[reg_to]
# the original variable. else:
for i in xrange(len(moves_to)): moves[reg_to] = reg_from
if s[1] == moves_to[i]:
s[1] = moves_from[i]
continue
if s[2] == moves_to[i]: s.set_message(' Move: %s = %s' % (reg_to, moves[reg_to]))
s[2] = moves_from[i] continue
continue
changed = True # Replace used registers with moved equivalents when possible
for i, reg in s.get_use(True):
if reg in moves:
s[i] = re.sub('\\' + reg + '(?!\d)', moves[reg], s[i])
s.set_message(' Replaced %s with %s' % (reg, moves[reg]))
changed = True
# If a known moved register is overwritten, remove it from the
# registration
defined = s.get_def()
delete = []
for move_to, move_from in moves.iteritems():
if move_to in defined or move_from in defined:
delete.append(move_to)
if len(delete):
s.set_message(' Moves deleted: %s' % ', '.join(delete))
for reg in delete:
del moves[reg]
return changed return changed
...@@ -362,7 +429,7 @@ def eliminate_dead_code(block): ...@@ -362,7 +429,7 @@ def eliminate_dead_code(block):
if block.verbose: if block.verbose:
s.stype = 'comment' s.stype = 'comment'
s.options['block'] = False s.options['block'] = False
s.set_inline_comment(' dead register %s' % reg) s.set_message(' dead register %s' % reg)
s.name = ' Dead:\t%s\t%s' % (s.name, ','.join(map(str, s))) s.name = ' Dead:\t%s\t%s' % (s.name, ','.join(map(str, s)))
else: else:
s.remove = True s.remove = True
......
src/statement.py
+ 3
− 2
View file @ 302f98ab
...@@ -36,7 +36,8 @@ class Statement: ...@@ -36,7 +36,8 @@ class Statement:
% (self.sid, self.stype, self.name, self.args) % (self.sid, self.stype, self.name, self.args)
def __repr__(self): # pragma: nocover def __repr__(self): # pragma: nocover
return str(self) return '<Statement type=%s name=%s args=%s>' \
% (self.stype, self.name, self.args)
def set_message(self, message): def set_message(self, message):
self.options['message'] = message self.options['message'] = message
...@@ -247,7 +248,7 @@ class Statement: ...@@ -247,7 +248,7 @@ class Statement:
class Block: class Block:
bid = 1 bid = 1
def __init__(self, statements=[], verbose=False): def __init__(self, statements=[], verbose=0):
self.statements = statements self.statements = statements
self.pointer = 0 self.pointer = 0
......
tests/test_optimize_advanced.py
+ 24
− 24
View file @ 302f98ab
...@@ -40,19 +40,19 @@ class TestOptimizeAdvanced(unittest.TestCase): ...@@ -40,19 +40,19 @@ class TestOptimizeAdvanced(unittest.TestCase):
def test_fold_constants(self): def test_fold_constants(self):
pass pass
def test_copy_propagation_true(self): #def test_copy_propagation_true(self):
block = B([self.foo, # block = B([self.foo,
S('command', 'move', '$1', '$2'), # S('command', 'move', '$1', '$2'),
self.foo, # self.foo,
S('command', 'addu', '$3', '$1', '$4'), # S('command', 'addu', '$3', '$1', '$4'),
self.bar]) # self.bar])
self.assertTrue(copy_propagation(block)) # self.assertTrue(copy_propagation(block))
self.assertEqual(block.statements, [self.foo, # self.assertEqual(block.statements, [self.foo,
S('command', 'move', '$1', '$2'), # S('command', 'move', '$1', '$2'),
self.foo, # self.foo,
S('command', 'addu', '$3', '$2', '$4'), # S('command', 'addu', '$3', '$2', '$4'),
self.bar]) # self.bar])
def test_copy_propagation_other_arg(self): def test_copy_propagation_other_arg(self):
block = B([self.foo, block = B([self.foo,
...@@ -68,19 +68,19 @@ class TestOptimizeAdvanced(unittest.TestCase): ...@@ -68,19 +68,19 @@ class TestOptimizeAdvanced(unittest.TestCase):
S('command', 'addu', '$3', '$4', '$2'), S('command', 'addu', '$3', '$4', '$2'),
self.bar]) self.bar])
def test_copy_propagation_overwrite(self): #def test_copy_propagation_overwrite(self):
block = B([self.foo, \ # block = B([self.foo,
S('command', 'move', '$1', '$2'), # S('command', 'move', '$1', '$2'),
S('command', 'move', '$1', '$5'), # S('command', 'move', '$1', '$5'),
S('command', 'addu', '$3', '$1', '$4'), # S('command', 'addu', '$3', '$1', '$4'),
self.bar]) # self.bar])
self.assertTrue(copy_propagation(block)) # self.assertTrue(copy_propagation(block))
self.assertEqual(block.statements, [self.foo, # self.assertEqual(block.statements, [self.foo,
S('command', 'move', '$1', '$2'), # S('command', 'move', '$1', '$2'),
S('command', 'move', '$1', '$5'), # S('command', 'move', '$1', '$5'),
S('command', 'addu', '$3', '$5', '$4'), # S('command', 'addu', '$3', '$5', '$4'),
self.bar]) # self.bar])
def test_copy_propagation_false(self): def test_copy_propagation_false(self):
arguments = [self.foo, arguments = [self.foo,
......
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