[lld] r319518 - Add an additional test for r319503.

[Rafael Avila de Espindola via llvm-commits]

Rui Ueyama <ruiu at google.com> writes:

> 960 and 1031 aren't that different, and not using the prime number
> shouldn't make change as long as the lengths of hash chains are not too
> biased (which I believe true).
>
> I took a quick look at `do_lookup_x` function in elf/dl-lookup.c in glibc,
> and looks like the penalty of hash collision is pretty low there (we just
> need to skip a uint32_t value for each collision.)
>
> So the difference is interesting.

I honestly don't have the time to test it further, but it is pretty
simple to experiment if you are interested:

* Build a regular release of llvm+clang+lld in directory build.
* Mount a tmpfs in build2
* Use build to configure (cmake) a llvm in build2 with BUILD_SHARED_LIBS
* Run ninja check-llvm
* Run perf stat/record llvm-lit ... (copy and past the command from
  ninja -v check-llvm)

Cheers,
Rafael