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# Author: R. W. Ford, STFC Daresbury Laboratory
# Modified: A. R. Porter, N. Nobre and S. Siso, STFC Daresbury Lab
'''Module providing a transformation from a PSyIR SIGN intrinsic to
PSyIR code. This could be useful if the SIGN intrinsic is not supported
by the back-end or if the performance of the inline code is better
than the intrinsic.
'''
from psyclone.psyir.transformations.intrinsics.intrinsic2code_trans import (
Intrinsic2CodeTrans)
from psyclone.psyir.transformations import Abs2CodeTrans
from psyclone.psyir.nodes import (
BinaryOperation, Assignment, Reference, Literal, IfBlock, IntrinsicCall)
from psyclone.psyir.symbols import DataSymbol, REAL_TYPE
[docs]class Sign2CodeTrans(Intrinsic2CodeTrans):
'''Provides a transformation from a PSyIR SIGN intrinsic node to
equivalent code in a PSyIR tree. Validity checks are also
performed.
The transformation replaces
.. code-block:: python
R = SIGN(A, B)
with the following logic:
.. code-block:: python
R = ABS(A)
if B < 0.0:
R = R*-1.0
i.e. the value of ``A`` with the sign of ``B``
'''
def __init__(self):
super().__init__()
self._intrinsic = IntrinsicCall.Intrinsic.SIGN
[docs] def apply(self, node, options=None):
'''Apply the SIGN intrinsic conversion transformation to the specified
node. This node must be a SIGN IntrinsicCall. The SIGN
IntrinsicCall is converted to equivalent inline code. This
is implemented as a PSyIR transform from:
.. code-block:: python
R = ... SIGN(A, B) ...
to:
.. code-block:: python
tmp_abs = A
if tmp_abs < 0.0:
res_abs = tmp_abs*-1.0
else:
res_abs = tmp_abs
res_sign = res_abs
tmp_sign = B
if tmp_sign < 0.0:
res_sign = res_sign*-1.0
R = ... res_sign ...
where ``A`` and ``B`` could be arbitrarily complex PSyIR
expressions, ``...`` could be arbitrary PSyIR code and where
``ABS`` has been replaced with inline code by the NemoAbsTrans
transformation.
This transformation requires the IntrinsicCall node to be a child of
an assignment and will raise an exception if this is not the case.
:param node: a SIGN IntrinsicCall node.
:type node: :py:class:`psyclone.psyir.nodes.IntrinsicCall`
:param symbol_table: the symbol table.
:type symbol_table: :py:class:`psyclone.psyir.symbols.SymbolTable`
:param options: a dictionary with options for transformations.
:type options: Optional[Dict[str, Any]]
'''
# pylint: disable=too-many-locals
self.validate(node, options)
symbol_table = node.scope.symbol_table
assignment = node.ancestor(Assignment)
# Create two temporary variables. There is an assumption here
# that the SIGN IntrinsicCall returns a PSyIR real type. This might
# not be what is wanted (e.g. the args might PSyIR integers),
# or there may be errors (arguments are of different types)
# but this can't be checked as we don't have the appropriate
# methods to query nodes (see #658).
res_var_symbol = symbol_table.new_symbol(
"res_sign", symbol_type=DataSymbol, datatype=REAL_TYPE)
tmp_var_symbol = symbol_table.new_symbol(
"tmp_sign", symbol_type=DataSymbol, datatype=REAL_TYPE)
# Replace operator with a temporary (res_var).
node.replace_with(Reference(res_var_symbol))
# Extract the operand nodes
_, op1, op2 = node.pop_all_children()
# res_var=ABS(A)
lhs = Reference(res_var_symbol)
rhs = IntrinsicCall.create(IntrinsicCall.Intrinsic.ABS, [op1])
new_assignment = Assignment.create(lhs, rhs)
assignment.parent.children.insert(assignment.position, new_assignment)
# Replace the ABS intrinsic with inline code.
abs_trans = Abs2CodeTrans()
abs_trans.apply(rhs, symbol_table)
# tmp_var=B
lhs = Reference(tmp_var_symbol)
new_assignment = Assignment.create(lhs, op2)
assignment.parent.children.insert(assignment.position, new_assignment)
# if_condition: tmp_var<0.0
lhs = Reference(tmp_var_symbol)
rhs = Literal("0.0", REAL_TYPE)
if_condition = BinaryOperation.create(BinaryOperation.Operator.LT,
lhs, rhs)
# then_body: res_var=res_var*-1.0
lhs = Reference(res_var_symbol)
lhs_child = Reference(res_var_symbol)
rhs_child = Literal("-1.0", REAL_TYPE)
rhs = BinaryOperation.create(BinaryOperation.Operator.MUL,
lhs_child, rhs_child)
then_body = [Assignment.create(lhs, rhs)]
# if [if_condition] then [then_body]
if_stmt = IfBlock.create(if_condition, then_body)
assignment.parent.children.insert(assignment.position, if_stmt)