On Wed, 16 Sep 2015 04:32:19 +0200 Andi Kleen <andi@xxxxxxxxxxxxxx> wrote: > > __iowrite32_copy() is marked __visible. I don't actually know what > > that does and Andi's d47d5c8194579bc changelog (which sucks the big > > one) didn't explain it. Apparently it has something to do with being > > implemented in assembly, but zillions of functions are implemented in > > assembly, so why are only two functions marked this way? Anyway, > > __ioread32_copy() is implemented in C so I guess __visible isn't needed > > there. > > __visible is needed for C functions that are called from assembler. > Otherwise the compiler may optimize them away. Under what circumstances will the compiler (or linker?) do this? LTO enabled?
