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

[Eric Christopher]

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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