Is LLVM really pulling ahead of gcc?

[Jakub Jelinek]

On Mon, Mar 03, 2014 at 10:20:10AM +0800, lin zuojian wrote:
>     I saw
>     http://www.phoronix.com/scan.php?page=article&item=llvm34_gcc49_compilers&num=1
>     And LLVM/clang beaten gcc in serval tests.But I ran that
>     tests,e.g.SciMark,it didn't appear to be like this on my i7 machine.Was that
>     article written by Apple?

See my comment there and various others, the phoronix "benchmarks" are usually
microbenchmarks where the results vary a lot from one run to another one,
I've very rarely have been actually able to reproduce anything close to the
numbers Michael posts, and even when e.g. in this January I've improved
predcom on one of the microbenchmarks a lot in GCC, no changes have been
visible in Michael's numbers afterwards.  I find his articles very
LLVM/clang biased and numbers untrustworthy.  Of course it makes sense
to us to look even at those microbenchmarks from time to time and try to
improve things if possible, often it is primarily about badly chosen
compiler options on the Phoronix side (say benchmarks needing -ffast-math
for vectorization and it not being supplied, so it is never vectorized by
any compiler).  SPEC is of course far more trustworthy benchmark.

	Jakub