[LLVMdev] does clang and llvm take more time to compile c code

[Eric Lu]

The options is
cmake -DCMAKE_BUILD_TYPE="Debug"  -DCMAKE_INSTALL_PREFIX=~software/llvmsvn
-DCMAKE_EXPORT_COMPILE_COMMANDS=ON /home/xxx/lsoftware/llvm-3.2-svn

$make
$make install


On Fri, Jun 28, 2013 at 12:37 PM, Eric Christopher <echristo at gmail.com>wrote:

> On Thu, Jun 27, 2013 at 6:04 PM, Eric Lu <eirc.lew at gmail.com> wrote:
> > Hi, Ben
> > gcc version is: 4.7.0
> > clang version is: 3.2
> >
> > The command options are:
> > 1) clang
> > generated object files: clang -O3 -c *.c -o x.o
> > link:  clang  *.o -lm -o  mpeg2enc
> >
> > 2) gcc
> > generated object files: gcc -O3 -c *.c -o x.o
> > link:  gcc  *.o -lm -o  mpeg2enc
> >
> >
> > Yes, maybe it is the config introduced problems, I build it with enable
> > debug options.
> >
>
> More the point did you build it optimized or unoptimized. Can you show
> your configure/make commands?
>
> -eric
>
> > Thanks!
> >
> > Eric
> >
> >
> >
> >
> > On Thu, Jun 27, 2013 at 7:49 PM, Benjamin Kramer <benny.kra at gmail.com>
> > wrote:
> >>
> >>
> >> On 27.06.2013, at 13:40, Eric Lu <eirc.lew at gmail.com> wrote:
> >>
> >> > Hello, all
> >> >
> >> > When I compile mpeg2enc of Mediabench, it seems clang and llvm take
> >> > longer time than gcc. I meausre the time as follow:
> >> >
> >> > gcc -O3   8.190s
> >> > clang  -O3  20.253s
> >> >
> >> > will this means clang and llvm are slower than gcc in compiling c
> code.
> >>
> >> Possibly. The timings are useless without information about the versions
> >> of GCC and clang used and the build configuration (clang is extremely
> slow
> >> when built without optimization).
> >>
> >> - Ben
> >
> >
> >
> > _______________________________________________
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> >
>
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