The goal of these runs is to compare the performance of the latest versions of LLVM and GCC on x86 in 64-bit mode. I used the following similar options:

LLVM-3.3 does not support -Ofast. Therefore we use -O3 -ffast-math for it.

LLVM can not produce a correct code for on any optimization level. Therefore -O0 was used instead of -O3 or -Ofast for all LLVM and GCC compilers for

LLVM-3.3 produces a wrong code for 256.bzip2 with -march=core-axv2. Therefore we use -march=corei7 instead for LLVM-3.3 and GCC-4.8.

The used machine is 3.4Ghz Intel Core i5-4670 (Haswell) with 16GB memory under Fedora Core20.

GCC-4.8/4.9 was configured with --enable-checking=release. LLVM-3.3/3.4 with CLANG for x86 were built in release mode. The sources are taken from LLVM download site. All changes are given relative to LLVM-3.3 run.

Last modified: 06/23/2014 - vmakarov at redhat dot com

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