def visit_BitVecShiftLeft(self, expression, *operands):
left = expression.operands[<NUM_LIT:0>]<EOL>right = expression.operands[<NUM_LIT:1>]<EOL>if isinstance(right, BitVecConstant):<EOL><INDENT>if right.value == <NUM_LIT:0>:<EOL><INDENT>return left<EOL><DEDENT>elif right.value >= right.size:<EOL><INDENT>return left<EOL><DEDENT><DEDENT>
a << 0 => a                       remove zero
            a << ct => 0 if ct > sizeof(a)    remove big constant shift