On Thu, Mar 12, 2009 at 12:08 PM, Joseph S. Myers <jos...@codesourcery.com> wrote: > On Thu, 12 Mar 2009, Diego Novillo wrote: > >> Since C treats enums as ints, the maximum value is always INT_MAX >> regardless of how many values are declared. So the question is, how >> should we lower enums into gimple? >> >> The temptation is to use C++'s limits, but I'm concerned that may >> produce confusion somewhere down the line with the optimizers or other >> diagnostics. Or should we use C's notion and treat them as ints? > > In C an enum type is always compatible with and represented the same as > some integer type, so using C++ limits could result in miscompilation of C > code using enums; if int is the type chosen, a variable of the enum type > may legitimately hold any value of type int, unlike in C++.
In addition to that, C++0x has the notion of 'class enum', which among other things, let user specify the underlying integral type (and this is per enum-definition basis). In anticipation to that, as I suspect that LTO would have to encode the underlying integral limits for each enum. -- Gaby
