Vector operators in which one operand is a scalar may not apply implicit conversions to the scalar operand in host emulation. For example, the following will result in a compilation error due to failing template argument deduction in host emulation:

uint8_t op2;
int16 foo(int * op1, int ch)

Workaround:
If the scalar operand is explicitly cast to the element type of the vector, no compilation error will occur in host emulation:

uint8_t op2;
int16 foo(int * op1, int ch)