Variable Not fully defined on some execution path error

I have some code that is inside a simulink block that gets an error when it's compiled. It says a variable is not fully defined on some execution paths, but it's not true.

Here's a simplified version of the code:

function myfunc(logicA, logicB)
A = logicA;
B = logicB;  % also input from the function
if A
    X = 1;
elseif B
    X = 2;
end
if (A || B)
    Y = X;
end

It complies fine if I change it to

function myfunc(logicA, logicB)
A = logicA;
B = logicB;  % also input from the function
X=2
if A
    X = 1;
end
if (A || B)
    Y = X;
end

It looks like the compiler doesn't realize that it doesn't need X if (A || B) is false?

Answer 1

[Walter Roberson]

disp(myfunc(1,1))

     1

disp(myfunc(1,0))

     1

disp(myfunc(0,1))

     2

disp(myfunc(0,0))

Output argument "Y" (and maybe others) not assigned during call to "solution>myfunc".

function Y = myfunc(logicA, logicB)
A = logicA;
B = logicB;  % also input from the function
if A
    X = 1;
elseif B
    X = 2;
end
if (A || B)
    Y = X;
end
end

[Walter Roberson]

The code would only be acceptable if you do not unconditionally use Y afterwards.

[John Petersen]

thanks.