https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63218
Bug ID: 63218
Summary: More compact std::bitset<n> for small n
Product: gcc
Version: 5.0
Status: UNCONFIRMED
Keywords: ABI
Severity: enhancement
Priority: P3
Component: libstdc++
Assignee: unassigned at gcc dot gnu.org
Reporter: glisse at gcc dot gnu.org
sizeof(std::bitset<1>) is 8 on x86_64. It would be nice if it was reduced a
bit. For efficiency reasons, it makes sense to keep std::bitset<65> of size 16,
but for anything using at most 32 bits, using a smaller underlying type would
be better.
I had already though about that a long time ago, and was reminded by reading:
https://groups.google.com/a/isocpp.org/d/msg/std-proposals/UjNcLLrGwv8/Pe1Icl6h6xQJ
(another ABI-breaking change in bitset would be to set _WordT to unsigned long
long on win64)
