On Wed, Jun 08, 2016 at 02:31:31AM -0700, H. Peter Anvin wrote: > On 06/08/16 02:20, Ingo Molnar wrote: > > > > Yeah, absolutely. I hate 'bool' with a vengence but if 'int' generates > > worse code > > with modern compilers then I'm not going to argue for worse code. Would a > > 'char' > > return type be very weird? > > > > Yes. I have to admit I don't share your hatred for "bool" -- it gives > the compiler a fairly crucial bit of information about what the possible > values are for a certain piece of data. > > Upcasting to char loses that, and may case gcc to manifest the value as > an integer instead of retaining it in the flags. It is, however, less > likely to cause gcc to then try to widen the value to word size (which > is an extra instruction on x86), but moving the value out of and back > into the flags register is the big cost.
So I think using bool as return type or argument is fine, using it in structures is 'insane'.
