[PATCH] D25277: [test-suite] Run FP tests twice with -ffp-contract=off/on

[Matthias Braun via llvm-commits]

> On Oct 6, 2016, at 7:30 AM, Sebastian Pop via llvm-commits <llvm-commits at lists.llvm.org> wrote:
> 
>> I don't plan big changes in the near future except for an additionol plugin to collect the llvm statistics generated by the new -save-stats clang flag...
> 
> I like this: I had also thought adding a test-suite mode to collect at
> compile time the output of -mllvm -stats.
> Please point me to your patches, keep me in the review loop, and let
> me know how I can help ;-)

I put a first version of this into the test-suite now (r283649). You can enable it with -DTEST_SUITE_COLLECT_STATS at cmake time (make sure your clang is new enough to understand -save-stats and has asserts enabled).

Future Work:
- We may want to add some filtering mechanism to not flood the output with too many values.
- LLVM should put the pass timings into the stats as well. At least when we output the .json file.
- Figure out how expensive the stats are and either always compile them into clang or provide a release build configuration with stats enabled.

- Matthias