[Bug rtl-optimization/122992] speed up loops with TEST_HARD_REG_BIT using EXECUTE_IF_SET_IN_HARD_REG_SET

[xry111 at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=122992

--- Comment #30 from Xi Ruoyao <xry111 at gcc dot gnu.org> ---
For LoongArch building a cross-compiler is not enough to catch the error as it
normally manifests in stage 3: stage 1 is built with -O0 which covers up the
issue so stage 2 can be successfully built, but then stage 2 fails to build
stage 3.

Like AArch64 you can also use a LoongArch machine via cfarm, but there are only
two of them.

I'm constructing a GCC build bot for LoongArch but currently the only thing it
can do is sending test reports like
https://gcc.gnu.org/pipermail/gcc-testresults/2026-June/877884.html.  I've not
added the functionality to automatically bisect and notify the patch author in
the event of a bootstrap failure yet.