[Bug c++/54021] [c++0x] __builtin_constant_p should be constexpr

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54021

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
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                 CC|                            |jakub at gcc dot gnu.org,
                   |                            |jason at gcc dot gnu.org

--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> 2012-07-19 06:53:11 UTC ---
This is rejected only at -O0 and quite matches how __builtin_constant_p
normally behaves at -O0 - you really need a constant right in the
__builtin_constant_p argument, everything else results in 0.  With -O1 and
above you get BUILTIN_CONSTANT_P not folded right away to 0 if not constant and
whether it in the end folds to 0 or 1 depends on optimization, whether a
constant is propagated to it or not.