[Bug c++/85747] suboptimal code without constexpr

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85747

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
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                 CC|                            |rguenth at gcc dot gnu.org

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
Well.  Besides of the C++ frontend the compiler has no facility to fully
evaluate a part of a program but for cases like this it would rely on
inlining then unrolling and then constant propagation.  All this work has
limits and heuristics and there are just cases where the heuristics need
to give up...

What's the reason for writing the code as you pasted it?

Note that sort isn't a const function since it modifies global memory.