[Bug c++/96197] New: Excess memory consumption, positive correlation with the size of a constexpr array

[hyena at hyena dot net.ee]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96197

            Bug ID: 96197
           Summary: Excess memory consumption, positive correlation with
                    the size of a constexpr array
           Product: gcc
           Version: 9.3.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: hyena at hyena dot net.ee
  Target Milestone: ---

Created attachment 48876
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=48876&action=edit
Contains the problematic constant expression array.

The memory consumption of the compiler seems to have an exponential dependency
on one of the constant expression arrays that I have set up in the header. I
have attached the header file. With an array of just 500 elements the memory
consumption of GCC goes above 5 GiB.

I have tested even with the latest 10.x version and the problem is still there.
Tested also with -O1, -O2 and -O3 and none of these made any difference.

If anyone is aware of any workarounds then I would much appreciate learning
more about them because I need to keep developing the project I have at hand
but because of this bug it has become impossible to continue without changing
the architecture a lot.

This only becomes noticeable at larger array sizes (several hundred elements in
my case).