[Bug c++/85461] A simple recursive TMP static const initializer defeats gcc

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85461

--- Comment #3 from Andrew Pinski  ---
Using constexpr is a decent workaround.
Note enum version of this is rejected by all compilers:
template
struct bitWidthHolding {
enum {width = (v == 0) ? 0 : bitWidthHolding<(v>>1)>::width + 1};
};
int a = bitWidthHolding<255>::width;

Which I find interesting.

[Bug c++/85461] A simple recursive TMP static const initializer defeats gcc

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85461

Jonathan Wakely  changed:

   What|Removed |Added

   Keywords||rejects-valid
 Status|UNCONFIRMED |NEW
   Last reconfirmed||2018-04-19
 Ever confirmed|0   |1

--- Comment #2 from Jonathan Wakely  ---
I think https://wg21.link/cwg712 makes this valid.

[Bug c++/85461] A simple recursive TMP static const initializer defeats gcc

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85461

Jakub Jelinek  changed:

   What|Removed |Added

 CC||jakub at gcc dot gnu.org

--- Comment #1 from Jakub Jelinek  ---
The testcase is incomplete, something like:
int a = bitWidthHolding<255>::width;
is missing, otherwise it doesn't fail.  The reason for giving up is that it
tries to instantiate bitWidthHolding<0> many times, doesn't seem to be a
regression, all gcc versions that have -std=c++0x support fail similarly.