Enzyme: Cannot cast __enzyme_autodiff primal argument 16

[efeklisov]

I'm getting a weird typecasting issue in Enzyme. What could be the source of it?

https://fwd.gymni.ch/vATLS0

[wsmoses]

Oh this might be clang splatting the args into two pieces. What happens if you change the function and enzyme call to pass everything by reference

…

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[efeklisov]

I hope I understood you correctly, but I see a similar issue

https://fwd.gymni.ch/TFoPoL

[wsmoses]

C var-args passes things by value, so you need to & the args to make them pointers in that case: https://fwd.gymni.ch/zWsQwn

[wsmoses]

Hopefully that solve your issue, however keeping this open for now so we can make the nice c++ syntax happy with it [and obviate the need for the extra work]: https://fwd.gymni.ch/UDe5lg

@samuelpmishLLNL @samuelpmish

[ipcamit]

Sorry, I am having same issue, in a small example I was creating to ask unrelated question. Why is the minimal function below gives same error?

https://fwd.gymni.ch/NzHCYv

int __enzyme_const, __enzyme_dup;

void __enzyme_autodiffs(void (*) (double, double, double*), ...);

void math(double a, double b , double *result) {}

void grad(double a, double b, double *result, double *d_result) {

    double d_a = 0.0;
    double d_b = 0.0;
    __enzyme_autodiffs(math,
        __enzyme_dup, a, d_a,
        __enzyme_dup, b, d_b,
        __enzyme_dup, result, d_result);

}

[samuelpmish]

@ipcamit I think you're just using the wrong names for some of the enzyme stuff.

try:

• __enzyme_autodiff rather than __enzyme_autodiffs
• enzyme_const instead of __enzyme_const
• enzyme_dup instead of __enzyme_dup

see: https://fwd.gymni.ch/k3qaoa

[ipcamit]

This is embarrassing! I was using __enzyme_autodiff properly, and was trying to see if its name change will affect the compilation. But completely forgot about enzyme_dup, I was really sure that all things enzyme start like __enzyme...! Thank you for taking time to look into this.