[llvm-dev] Uncovering non-determinism in LLVM - The Next Steps

[Jack Howarth via llvm-dev]

       FYI, I just successfully performed a 3-stage bootstrap with
stage2/stage3 object file comparison on x86_64-apple-darwin16 for
llvm/clang/clang-tools-extra/compiler-rt/libcxx/openmp/polly using our
custom fink packaging scripts with the
-DLLVM_REVERSE_ITERATION:BOOL=ON cmake option. There were no
stage2/stage3 object file comparison failures or test suite
regressions.
       I do have one question though. Is there any particular reason
not to leave this option on for deployed release builds of the
compiler? Other than possibly running into some extreme corner case of
non-deterministism that the stage2/stage3 comparisons and test suites
miss, is there any performance issues introduced in compile time by
leaving  -DLLVM_REVERSE_ITERATION:BOOL=ON defaulted on? Thanks in
advance for any clarifications.
            Jack
ps Is it still the case that none of the llvm.org build bots are doing
a full 3-stage bootstrap with stage2/stage3 file comparison (ala FSF
gcc)? If so, that seems like an unfortunate gap in the llvm compiler
testing.