CODEWITHSUNDEEP
clang
GoZoner
GoZoner

Reputation: 70145

Dramatically Slower Compilation Time vs GCC

I'm seeing a factor of four slowdown in Clang compilation versus GCC. Any idea what causes this?

ebg@tsuki(250)$ time /usr/bin/cc -DHC4 -DSAFETY -DNOREDUCE -DNFAIR=3 -O2  -o files2 pan.c    
real    2m3.073s
user    1m59.484s
sys 0m3.585s

ebg@tsuki(251)$ time /usr/local/gcc/bin/gcc -DHC4 -DSAFETY -DNOREDUCE -DNFAIR=3 -O2  -o files1 pan.c
real    0m28.310s
user    0m27.590s
sys 0m0.706s

ebg@tsuki(252)$ /usr/bin/cc -v
Apple clang version 4.0 (tags/Apple/clang-421.0.60) (based on LLVM 3.1svn)
Target: x86_64-apple-darwin12.2.0
Thread model: posix

ebg@tsuki(253)$ /usr/local/gcc/bin/gcc -v
Using built-in specs.
COLLECT_GCC=/usr/local/gcc/bin/gcc
COLLECT_LTO_WRAPPER=/usr/local/gcc/libexec/gcc/x86_64-apple-darwin10.7.0/4.6.0/lto-wrapper
Target: x86_64-apple-darwin10.7.0
Configured with: ./configure --prefix=/usr/local/gcc --enable-languages='c c++' --enable-lto --with-gmp=/usr/local/gcc --with-mpfr=/usr/local/gcc --with-mpc=/usr/local/gcc
Thread model: posix
gcc version 4.6.0 (GCC)

Upvotes: 3

Views: 1043

Answers (1)

Kocka
Kocka

Reputation: 1894

When I had the same problem it was due to clang was build for debug mode and not for release mode.

Upvotes: 3

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