[MrBurmark]

Add a constant type that takes a compile-time value as a template parameter. Support arithmetic between constants that produces a constant.

constant<0> zero;
constant<1> one;
auto two = one + one;
static_assert(two == 2);
static_assert(std::same_as<decltype(two), constant<2>>);

The ultimate goal with this is use it as part of a RAJA::transparent_range class that I'm thinking about adding that stores the input begin, end, and stride exactly as they were given. My hope is to improve some cases in RAJAPerf and beyond where the BASE and RAJA differ by knowledge of such exact values. For example we often assume that ranges start at 0 but RAJA ranges always have a runtime begin value, knowledge of which does not cross the host device barrier. This is responsible for some differences between kernel which takes its ranges on the host and launch which takes ranges on the device.

[rhornung67]

@MrBurmark I'm OK with this going in for the patch release, but I will leave the final call up to you. If this will require changes to user code, is it too much for a patch release? Also, where should we document those changes?

[MrBurmark]

I'll remove the places that this was used in favor or integral_constant for compatibility.

[MrBurmark]

I reverted the places where constant was used inplace of constant so user code doesn't have to change.

[adayton1]

Can you update the pull request description now that integral_constant is no longer being deprecated?

[MrBurmark]

Can you update the pull request description now that integral_constant is no longer being deprecated?

done.