def transform_unary_minus_expr(self,
unary_minus: ir.UnaryMinusExpr) -> ir.Expr:
expr = self.transform_expr(unary_minus.inner_expr)
# -(3) => -3
if isinstance(expr, ir.Literal):
assert isinstance(expr.value, int)
return ir.Literal(-expr.value)
# -(x - y) => y - x
if isinstance(expr, ir.Int64BinaryOpExpr) and expr.op == '-':
return ir.Int64BinaryOpExpr(lhs=expr.rhs, rhs=expr.lhs, op='-')
return ir.UnaryMinusExpr(expr)
def transform_int64_binary_op_expr(
self, binary_op: ir.Int64BinaryOpExpr) -> ir.Expr:
lhs = binary_op.lhs
rhs = binary_op.rhs
op = binary_op.op
# (x - y) => (x + -y)
# This pushes down the minus, so that e.g. (x - (-y)) => (x + y).
if op == '-':
rhs = ir.UnaryMinusExpr(rhs)
op = '+'
lhs = self.transform_expr(lhs)
rhs = self.transform_expr(rhs)
if op == '+' and isinstance(rhs, ir.UnaryMinusExpr):
# We could not push down the minus, so switch back to a subtraction.
op = '-'
rhs = rhs.inner_expr
if op == '+':
# 3 + 5 => 8
if isinstance(lhs, ir.Literal) and isinstance(rhs, ir.Literal):
return ir.Literal(lhs.value + rhs.value)
# 0 + x => x
if isinstance(lhs, ir.Literal) and lhs.value == 0:
return rhs
# x + 0 => x
if isinstance(rhs, ir.Literal) and rhs.value == 0:
return lhs
if op == '-':
# 8 - 5 => 3
if isinstance(lhs, ir.Literal) and isinstance(rhs, ir.Literal):
return ir.Literal(lhs.value - rhs.value)
# 0 - x => -x
if isinstance(lhs, ir.Literal) and lhs.value == 0:
return ir.UnaryMinusExpr(rhs)
# x - 0 => x
if isinstance(rhs, ir.Literal) and rhs.value == 0:
return lhs
if op == '*':
# 3 * 5 => 15
if isinstance(lhs, ir.Literal) and isinstance(rhs, ir.Literal):
return ir.Literal(lhs.value * rhs.value)
# 0 * x => 0
if isinstance(lhs, ir.Literal) and lhs.value == 0:
if self._can_remove_subexpression(rhs):
return ir.Literal(0)
# x * 0 => 0
if isinstance(rhs, ir.Literal) and rhs.value == 0:
if self._can_remove_subexpression(lhs):
return ir.Literal(0)
# 1 * x => x
if isinstance(lhs, ir.Literal) and lhs.value == 1:
return rhs
# x * 1 => x
if isinstance(rhs, ir.Literal) and rhs.value == 1:
return lhs
if op == '/':
# 16 / 3 => 5
if isinstance(lhs, ir.Literal) and isinstance(rhs, ir.Literal):
return ir.Literal(lhs.value // rhs.value)
# x / 1 => x
if isinstance(rhs, ir.Literal) and rhs.value == 1:
return lhs
if op == '%':
# 16 % 3 => 1
if isinstance(lhs, ir.Literal) and isinstance(rhs, ir.Literal):
return ir.Literal(lhs.value % rhs.value)
# x % 1 => 0
if isinstance(rhs, ir.Literal) and rhs.value == 1:
return ir.Literal(0)
return ir.Int64BinaryOpExpr(lhs, rhs, op)
def transform_int64_binary_op_expr(
self, binary_op: ir.Int64BinaryOpExpr) -> ir.Expr:
lhs, rhs = self.transform_exprs([binary_op.lhs, binary_op.rhs],
binary_op)
return ir.Int64BinaryOpExpr(lhs=lhs, rhs=rhs, op=binary_op.op)