GCC 8.0 vs. LLVM Clang 6.0 On AMD EPYC

Written by Michael Larabel in Software on 13 January 2018 at 08:20 AM EST. Page 3 of 3. 10 Comments.
GCC 8.0 vs. Clang 6.0 AMD EPYC Tuning Comparison
GCC 8.0 vs. Clang 6.0 AMD EPYC Tuning Comparison
GCC 8.0 vs. Clang 6.0 AMD EPYC Tuning Comparison

Znver1 was also of some benefit in the GraphicsMagick benchmarking, but Clang was trailing behind GCC 8.0 with its OpenMP implementation not being as strong.

GCC 8.0 vs. Clang 6.0 AMD EPYC Tuning Comparison

In the Himeno pressure solver benchmark, znver1 targeting regressed GCC 8's performance while Clang 6.0 saw a slight improvement in performance and was in first place for this test.

GCC 8.0 vs. Clang 6.0 AMD EPYC Tuning Comparison

Ebizzy was another test example where GCC 8 didn't see much out of znver1 while Clang 6.0 did. GCC 8 has seen znver1 improvements, but it looks like it (as well as LLVM/Clang) could still see more optimization work for these Zen CPU cores.

GCC 8.0 vs. Clang 6.0 AMD EPYC Tuning Comparison

With the C-Ray multi-threaded ray-tracer the scenario was opposite where znver1 really helped GCC 8 but was of minimal help to Clang 6.0.

GCC 8.0 vs. Clang 6.0 AMD EPYC Tuning Comparison

Znver1 really helped Clang with FLAC audio encoding to secure a first place finish.

GCC 8.0 vs. Clang 6.0 AMD EPYC Tuning Comparison

But with LAME MP3 encoding, znver1 tuning regressed Clang's performance.

Those wishing to dig through more of this compiler benchmark data can continue to OpenBenchmarking.org for additional benchmark results.

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Michael Larabel

Michael Larabel is the principal author of Phoronix.com and founded the site in 2004 with a focus on enriching the Linux hardware experience. Michael has written more than 20,000 articles covering the state of Linux hardware support, Linux performance, graphics drivers, and other topics. Michael is also the lead developer of the Phoronix Test Suite, Phoromatic, and OpenBenchmarking.org automated benchmarking software. He can be followed via Twitter, LinkedIn, or contacted via MichaelLarabel.com.