[llvm] [Premerge] Add flang-rt (PR #128678)

[Aiden Grossman via llvm-commits]

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@@ -47,6 +48,7 @@ function compute-projects-to-test() {
       # Flang is not stable in Windows CI at the moment
       if [[ $isForWindows == 0 ]]; then
         echo flang
+        echo flang-rt
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boomanaiden154 wrote:

Have you tested this locally? I don't think this will work as is. On Linux the runtimes explicitly built through the runtimes build are in https://github.com/llvm/llvm-project/blob/6eefadd8efc0584211cb5283e0acc00a45588242/.ci/monolithic-linux.sh#L95

I would think the path to Flang would need to be passed in there? No idea how the plumbing works for `flang-rt` though. The runtimes are also built three separate times in different C++ configurations, which doesn't make sense for a library written in Fortran, although looking at the source, it seems like most of it is in C++?

If this isn't a necessary change for keeping the flang build working, it might be worth just waiting until I've had a chance to rework how we test runtimes in premerge.

https://github.com/llvm/llvm-project/pull/128678