Compiler Benchmarks Of GCC, LLVM-GCC, DragonEgg, Clang

[phoronix]

Phoronix: Compiler Benchmarks Of GCC, LLVM-GCC, DragonEgg, Clang

LLVM 2.8 was released last month with the Clang compiler having feature-complete C++ support, enhancements to the DragonEgg GCC plug-in, a near feature-complete alternative to libstdc++, a drop-in system assembler, ARM code-generation improvements, and many other changes. With there being great interest in the Low-Level Virtual Machine, we have conducted a large LLVM-focused compiler comparison at Phoronix of GCC with versions 4.2.1 through 4.6-20101030, GCC 4.5.1 using the DragonEgg 2.8 plug-in, LLVM-GCC with LLVM 2.8 and GCC 4.2, and lastly with Clang on LLVM 2.8.

http://www.phoronix.com/vr.php?view=15422

[misiu_mp]

What happened there at graphics magic tests? Do the newer gccs utilize OpenMP that much better?

[yoshi314]

While LLVM/Clang is not yet decisively faster than GCC, it is continuing to make great progress and does boast a different feature-set and focus from the GNU Compiler Collection.

this template footer found in nearly every phoronix article, sounds like "please disregard this article, it's going to be obsolete soon"

[jakubo]

quite nice.
it seems llvm likes c-ray but no chess.
what id like to see now is a linux kernel (compiled with these different compilers) performance benchmark.

a thing that bothers me aswell is the fact that there are being "regressions found" on intel cpu whereas there is a huge performance improvement on AMD (or vice versa). maybe one should take this into account when looking for regressions. as far as i remember there have only been benchmarks with intel hardware...
and as the graphs show there really are some interesting splits in performance with different hardware

[nanonyme]

quite nice.
it seems llvm likes c-ray but no chess.
what id like to see now is a linux kernel (compiled with these different compilers) performance benchmark.

Last I heard, can't be done with llvm.

[nanonyme]

Sorry, that was ambiguous. As in, Linux kernel compiling can't be done with llvm.

[ChrisXY]

I may have missed it but what optimizations were used for these tests (especially for gcc)?

-march=native -mtune=native -fomit-frame-pointer -O3

More, less?

[nanonyme]

-mtune=native is redundant if you're using -march=native.
-fomit-frame-pointer breaks debuggability in x86.
-O3 has bugs and might slow down run-time in many cases.

[Tgui]

Good article, nice graphs and happy bday!

I'd bet with time that LLVM using compilers will catch up to GCC in the rest of the tests.

[Shining Arcanine]

What compiler flags were used to build each package? These benchmarks are out of context without that information.