[cfe-dev] Clang on Windows targteing gcc compiles very slowly

[Dennis Luehring]

im using the cl-clang vstudio plugin binary from the homepage and it 
compiles slower (nearly 2 times i think) then cl

Am 31.05.2015 um 07:40 schrieb Nico Weber:
> Can you post the cmake invocation you use?
>
> In general, we see clang being faster than gcc on linux/mac, and about as
> fast as cl.exe on windows on our bots. It sounds like you don't configure
> your build correctly. (clang-built-by-clang is a bit faster than
> clang-built-by-cl on windows; I don't know how clang-built-by-clang and
> clang-built-by-gcc on windows compare. But if you're seeing a 2-3x
> slowdown, you're probably accidentally doing a debug build of clang
> somehow.)
>
> On Sat, May 30, 2015 at 9:57 PM, Francois Pichet <pichet2000 at gmail.com>
> wrote:
>
> > I just noticed that assert is turned on even in Release on Windows
> > Is that on purpose? (seems like a bug to me)
> >
> > Anyway if I build clang with "LLVM_ENABLE_ASSERTIONS:BOOL=OFF" the build
> > get stuck at verifier.cpp from LLVMCore. CL.exe is stuck in an infinite
> > loop.
> >
> > I am using MSVC 2013 Update 5.
> >
> > On Sat, May 30, 2015 at 10:30 AM, Reid Kleckner <rnk at google.com> wrote:
> >
> >> You said you configured in release mode, but assertions might still be
> >> on. That accounts for a 2x slowdown. Otherwise I'd say that we haven't
> >> profiled and optimized clang on windows very much.
> >>
> >> Sent from phone
> >> On May 29, 2015 4:51 PM, "Edward Diener" <eldlistmailingz at tropicsoft.com>
> >> wrote:
> >>
> >>> I test Boost libraries mostly on Windows using various version of gcc
> >>> 4.3 and up, VC++ 8.0 and up, and the latest version of clang which I build
> >>> from source using mingw/gcc-4.8.1 in release mode.
> >>>
> >>> While clang is a great compiler when it comes to testing code, getting
> >>> intelligent error message, and implementing the latest C++ standard, it is
> >>> noticably slower ( 2x or 3x at minimum ) than the other compilers I use.
> >>>
> >>> The clang command line parameters usually being used are usually along
> >>> the lines of:
> >>>
> >>> -c -x c++ -O0 -g -fno-inline -Wall -g -march=i686 -m32
> >>>
> >>> with the addition of 'std=c++11' occasionally depending on the test.
> >>>
> >>> Does anybody have any idea why clang is so much slower than any of the
> >>> other compilers I use ? It does not seem to matter whether it is in C++03
> >>> mode or C++11 mode, it is noticeably slower than the other compilers.
> >>>
> >>> _______________________________________________
> >>> cfe-dev mailing list
> >>> cfe-dev at cs.uiuc.edu
> >>> http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev
> >>>
> >>
> >> _______________________________________________
> >> cfe-dev mailing list
> >> cfe-dev at cs.uiuc.edu
> >> http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev
> >>
> >>
> >
> > _______________________________________________
> > cfe-dev mailing list
> > cfe-dev at cs.uiuc.edu
> > http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev
> >
> >
>
>
>
> _______________________________________________
> cfe-dev mailing list
> cfe-dev at cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev