[cfe-dev] PCRE compiles fines and passes the test suite :)
snaroff at apple.com
Thu Jan 31 10:22:52 CST 2008
On Jan 31, 2008, at 7:37 AM, Nuno Lopes wrote:
>>> compiler | compile+link time | test suite run time | binary size
>>> gcc 4.1 | 17s | 1.9s | 43KB
>>> clang+llvm | 1m 13s | 1.4s | 188KB
>>> Although llvm is much slower at compiling (the linking part seems
>>> to be
>>> really slow due to the -O2 optimizations), the binary produced is
>>> faster :)
>> This doesn't makes sense to me. Are you using an optimized "release"
>> version of clang?
> no, it was a debug build. With a release build of llvm, it takes
> only 10
> seconds to build pcre! It's even faster than gcc 4.1 :)
> Of course this could still be better because of the overhead of the
Much better...:-) I'd be surprised if ccc is introducing much
overhead. The best way to know is to measure. If you are running on
Mac OS X, Shark is a wonderful performance analysis tool to tell us
exactly where the overhead is.
>>> P.S.2.: why isn't LLVM deployed to replace gcc? isn't it capable
>>> to act
>>> as a
>>> drop-in replacement for gcc with the gcc front-end (for now)?
> Noone tackle this question.. My question is for real: can llvm
> already be
> used as a drop-in replacement of gcc or not? e.g. can I already
> rebuild my
> gentoo system (including the kernel) with llvm? :)
Chris is in the best position to answer your question (which is why I
didn't respond to it).
> P.S.: the clang build is currently broken because of a commit to
Good catch! Hopefully this will be fixed soon...
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