Eric Lu
2013-Jun-29 15:41 UTC
[LLVMdev] does clang and llvm take more time to compile c code
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 > > > > > > > > _______________________________________________ > > LLVM Developers mailing list > > LLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.edu > > http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev > > >-------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20130629/fd3464d1/attachment.html>
Eli Friedman
2013-Jun-29 16:04 UTC
[LLVMdev] does clang and llvm take more time to compile c code
On Sat, Jun 29, 2013 at 8:41 AM, Eric Lu <eirc.lew at gmail.com> wrote:> 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 > > That would do it; Debug builds are roughly 2x slower than Release builds.-Eli -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20130629/4fd46ee9/attachment.html>
Caldarale, Charles R
2013-Jun-29 16:17 UTC
[LLVMdev] does clang and llvm take more time to compile c code
> From: llvmdev-bounces at cs.uiuc.edu [mailto:llvmdev-bounces at cs.uiuc.edu] > On Behalf Of Eli Friedman > Subject: Re: [LLVMdev] does clang and llvm take more time to compile c code> That would do it; Debug builds are roughly 2x slower than Release builds.We've found the ratio to be much higher than that - approaching 10x when compiling something with high optimization levels. - Chuck THIS COMMUNICATION MAY CONTAIN CONFIDENTIAL AND/OR OTHERWISE PROPRIETARY MATERIAL and is thus for use only by the intended recipient. If you received this in error, please contact the sender and delete the e-mail and its attachments from all computers.
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