On Wed, Apr 16, 2014 at 11:46:14AM +0200, Tom de Vries wrote:
> >...why do we need two different mechanisms to deal with these two?
> >IMO the set recorded for the callee should contain what the callee
> >instructions clobber and nothing else. CALL_INSN_FUNCTION_USAGE
> >should contain everything clobbered by a call outside the callee,
> >whether that's in the calling function itself, in a PLT, in a MIPS16
> >stub, or whatever.
Always putting all call clobbered registers to C_I_F_U explicitly
can be a serious memory hog on some architectures, e.g. doesn't
ia64 have ~ 160 call clobbered hard registers, times number of calls in a
function (sometimes tens of thousands)?
Jakub
