This started as an off hand comment in  but this appears to be a
real issue so I'm moving the discussion to the mailing list.
In r270942 the time taken to run LibFuzzer's test became noticeably
longer. I am building on
* Arch Linux (4.5.4-1-ARCH #1 SMP PREEMPT Wed May 11 22:21:28 CEST
2016 x86_64 GNU/Linux)
* I am building libFuzzer and running its tests like so
CC=<new_clang> CXX=<new_clang++> cmake -DLLVM_USE_SANITIZE_COVERAGE=1 -DLLVM_USE_SANITIZER=Address -DCMAKE_BUILD_TYPE=RELEASE ../src/ && make check-fuzzer -j8
where ``<new_clang>`` and ``<new_clang++>`` point to a recently built
clang (llvm: r270960 , clang: r270962 , compiler-rt: r270949) which
itself was compiled using gcc 6.1.1.
In r270937 (prior commit) the time to run the tests was ~25 seconds on
my machine but for the subsequent commit ( r270942 ) the tests took
If I run the tests
cd lib/Fuzzer/test python2 ../../../bin/llvm-lit -v --time-tests -j1 .
then I can observe the time it is taking to run the tests.
# For r270942
crash-log.txt.xz (40.2 KB)