On Fri, 9 Mar 2018 16:28:51 -0800 Linus Torvalds <torva...@linux-foundation.org> wrote:
> On Fri, Mar 9, 2018 at 4:07 PM, Andrew Morton <a...@linux-foundation.org> > wrote: > > > > A brief poke failed to reveal a workaround - gcc-4.4.4 doesn't appear > > to know that __builtin_constant_p(x) is a constant. Or something. > > LOL. > > I suspect it might be that it wants to evaluate > __builtin_choose_expr() at an earlier stage than it evaluates > __builtin_constant_p(), so it's not that it doesn't know that > __builtin_constant_p() is a constant, it just might not know it *yet*. > > Maybe. > > Side note, if it's not that, but just the "complex" expression that > has the logical 'and' etc, maybe the code could just use > > __builtin_constant_p((x)+(y)) > > or something. I'll do a bit more poking at it. > But yeah: > > > Sigh. Wasn't there some talk about modernizing our toolchain > > requirements? > > Maybe it's just time to give up on 4.4. We wanted 4.5 for "asm goto", > and once we upgrade to 4.5 I think Arnd said that no distro actually > ships it, so we might as well go to 4.6. > > So maybe this is just the excuse to finally make that official, if > there is no clever workaround any more. I wonder which gcc versions actually accept Kees's addition.
