cmov: Set asm options

[KamilaBorowska]

Those options tell the compiler that ASM statements do not read or write memory, can be removed if the dst ends up unused during compilation, and that they don't push data to the stack.

This can help compiler generate more optimal code. See https://doc.rust-lang.org/nightly/reference/inline-assembly.html#options for documentation of those options.

[tarcieri]

Thanks!

[newpavlov]

Is it correct to use nomem here? The goal of the blocks is to literally write data to dst if condition is met. Same for pure, IIUC writing to a pointer makes blocks not pure.

[KamilaBorowska]

Is it correct to use nomem here? The goal of the blocks is to literally write data to dst if condition is met. Same for pure, IIUC writing to a pointer makes blocks not pure.

asm block is not writing to memory, rather, it's writing to a register. Handling dereferences from and to register is on Rust side.