Linked by Thom Holwerda on Thu 7th Oct 2010 19:10 UTC, submitted by tyrione
General Development LLVM 2.8 has been released. The release notes describe this new, ehm, release in greater detail, so head on over and give it a read.
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RE: GCC > LLVM
by nt_jerkface on Fri 8th Oct 2010 17:41 UTC in reply to "GCC > LLVM"
nt_jerkface
Member since:
2009-08-26

Best at what? I thought it was common knowledge that icc is better for performance.
http://multimedia.cx/eggs/icc-vs-gcc-smackdown-round-3/

GCC is of course more portable but I wouldn't call it the best.

Reply Parent Score: 2

RE[2]: GCC > LLVM
by jacquouille on Fri 8th Oct 2010 17:51 in reply to "RE: GCC > LLVM"
jacquouille Member since:
2006-01-02

Best at what? I thought it was common knowledge that icc is better for performance.


Outdated common knowledge, then. GCC has improved very fast for the past 5 years now in the performance area, and simultaneously the nature of compiler optimization has shifted: 5 years ago it was mostly about the back-end carefully selecting asm instructions, which ICC is very good at, but nowadays programmers of performance-critical software use more and more intrinsics (especially for SIMD) so to a large extent they control that themselves. In other words, ICC's superiority in the area of auto-vectorization is becoming irrelevant as that doesn't get nearly as good as intrinsics-based vectorization anyway. Instead, compiler optimization has been moving to a larger scale, with e.g. the advanced loop transformations (polyhedral model) introduced in gcc 4.4, with partial loop unrolling, partial function inlining, better constants propagation, etc.

Reply Parent Score: 3

RE[3]: GCC > LLVM
by nt_jerkface on Fri 8th Oct 2010 18:18 in reply to "RE[2]: GCC > LLVM"
nt_jerkface Member since:
2009-08-26

Talk is cheap, real benchmarks are more telling.

The one I provided was from 2009.

Here's another from 2010:
http://macles.blogspot.com/2010/08/intel-atom-icc-gcc-clang.html

Here is another:
http://www.luxrender.net/forum/viewtopic.php?f=21&t=603

ffmpeg benchmark:
http://geminialpha.blogspot.com/2008/03/icc-vs-gcc-43.html

Here is someone showing how clamav can be recompiled with icc for a significant performance boost:
http://groups.google.com/group/linuxdna/browse_thread/thread/36a354...

I see no reason why I should believe that GCC will create a faster binary in most cases. But if you would like to convince me otherwise then pick some commonly used open source programs and create your own benchmarks.

Reply Parent Score: 3