Anyone here has benchmarked Intel C++ compiler and GCC?

Question

I am not sure whether I should post this question here, because this seems to be a programming-oriented website.

Anyway, I think there must be some gurus here who knows

Answer 1

I suppose it varies depending on the code, but with the codebase I am working on now, ICC 11.035 gives an almost 2x improvement over gcc 4.4.0 on a Xeon 5504.

icc options: -O2 -fno-alias
gcc options: -O3 -msse3 -mfpmath=sse -fargument-noalias-global

The options are specific to just the file containing the compute-intensive code, where I know there is no aliasing. Single-threaded code with a 5-level nested loop.

Although autovectorization is enabled, neither compilers generate vectorized code (not a fault of the compilers)

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Update (2015/02/27): While optimizing some geophysics code (Q2, 2013) to run on Sandy Bridge-E Xeons, I had an opportunity to compare the performance of ICC 11.1 against GCC 4.8.0, and GCC was now generating faster code than ICC. The code made used of AVX intrinsics and did use 8-way vectorized instructions (nieither compiler autovectorized the code properly due to certain data layout requirements). In addition, GCC's LTO implementation (with the IR core embedded in the .o files) was much easier to manage than that in ICC. GCC with LTO was running roughly 3 times faster than ICC without LTO. I'm not able to find the numbers right now for GCC without LTO, but I recall it was still faster than ICC. It's by no means a general statement on ICC's performance, but the results were sufficient for us to go ahead with GCC 4.8.*.

Looking forward to GCC 5.0 (http://www.phoronix.com/scan.php?page=article&item=gcc-50-broadwell)!

Answer 2

There is an interesting PDF here which compares a number of compilers.

Answer 3

PHP - Compilation from source, with ICC rather than GCC, should result in a 10 % to 20 % speed improvment - http://www.papelipe.no/tags/ez_publish/benchmark_of_intel_compiled_icc_apache_php_and_apc

MySQL - Compilation from source, with ICC rather than GCC, should result in a 25 % to 50 % speed improvment - http://www.mysqlperformanceblog.com/files/presentations/LinuxWorld2005-Intel.pdf