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from rpython.flowspace.model import Variable, Constant
from rpython.translator.backendopt.support import log
from rpython.translator import simplify
def remove_unaryops(graph, opnames):
"""Removes unary low-level ops with a name appearing in the opnames list.
"""
positions = []
touched_blocks = set()
for block in graph.iterblocks():
for i, op in enumerate(block.operations):
if op.opname in opnames:
positions.append((block, i))
while positions:
block, index = positions.pop()
op_result = block.operations[index].result
op_arg = block.operations[index].args[0]
# replace the new variable (op_result) with the old variable
# (from all subsequent positions)
for op in block.operations[index:]:
if op is not None:
for i in range(len(op.args)):
if op.args[i] == op_result:
op.args[i] = op_arg
if (op.opname == "indirect_call"
and isinstance(op.args[0], Constant)):
op.opname = "direct_call"
op.args = op.args[:-1]
for link in block.exits:
for i in range(len(link.args)):
if link.args[i] == op_result:
link.args[i] = op_arg
if block.exitswitch == op_result:
if isinstance(op_arg, Variable):
block.exitswitch = op_arg
else:
simplify.replace_exitswitch_by_constant(block, op_arg)
block.operations[index] = None
touched_blocks.add(block)
# remove all operations
for block in touched_blocks:
if block.operations:
block.operations[:] = filter(None, block.operations)
def remove_same_as(graph):
remove_unaryops(graph, ["same_as"])
def remove_duplicate_casts(graph, translator):
simplify.join_blocks(graph)
num_removed = 0
# remove chains of casts
for block in graph.iterblocks():
comes_from = {}
for op in block.operations:
if op.opname == "cast_pointer":
if op.args[0] in comes_from:
from_var = comes_from[op.args[0]]
comes_from[op.result] = from_var
if from_var.concretetype == op.result.concretetype:
op.opname = "same_as"
op.args = [from_var]
num_removed += 1
else:
op.args = [from_var]
else:
comes_from[op.result] = op.args[0]
if num_removed:
remove_same_as(graph)
# remove duplicate casts
for block in graph.iterblocks():
available = {}
for op in block.operations:
if op.opname == "cast_pointer":
key = (op.args[0], op.result.concretetype)
if key in available:
op.opname = "same_as"
op.args = [available[key]]
num_removed += 1
else:
available[key] = op.result
if num_removed:
remove_same_as(graph)
# remove casts with unused results
for block in graph.iterblocks():
used = {}
for link in block.exits:
for arg in link.args:
used[arg] = True
for i, op in list(enumerate(block.operations))[::-1]:
if op.opname == "cast_pointer" and op.result not in used:
del block.operations[i]
num_removed += 1
else:
for arg in op.args:
used[arg] = True
if translator.config.translation.verbose:
log.removecasts(
"removed %s cast_pointers in %s" % (num_removed, graph.name))
return num_removed
def remove_debug_assert(graph):
for block in graph.iterblocks():
for i, op in list(enumerate(block.operations))[::-1]:
if op.opname == "debug_assert":
del block.operations[i]
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