[LLVMdev] Any reason why fastcc on x86 shouldn't use ECX as a return register?

[Duncan Sands]

Hi Kenneth,

> Now that we can safely return arbitrarily large structs on x86, it
> seems to me that fastcc, which doesn't have to conform to any
> preexisting ABI, should use ECX as well as EAX and EDX for returning
> {i32,i32,i32} rather than use sret-demotion.

the x86 trampoline lowering code would need tweaking to check that the ECX
register was available for it.

Ciao,

Duncan.