1. Computers
  2. Display Drivers
  3. Graphics Cards
  4. Memory
  5. Motherboards
  6. Processors
  7. Software
  8. Storage
  9. Operating Systems


Facebook RSS Twitter Twitter Google Plus


Phoronix Test Suite

OpenBenchmarking.org

The Best Features Of LLVM / Clang 3.3

Compiler

Published on 26 May 2013 01:16 PM EDT
Written by Michael Larabel in Compiler
4 Comments

With next month's release of LLVM 3.3 quickly approaching, here's an overview of some of the best and most exciting features coming to this next major update of the LLVM compiler infrastructure and Clang C/C++ compiler front-end.

Some of our favorite features coming to LLVM 3.3 include:

- Exciting many Phoronix readers will be the final integration of the AMD R600 GPU LLVM back-end. This LLVM back-end that's needed for Radeon Gallium3D Compute/OpenCL along with RadeonSI acceleration is finally found in a mainline LLVM release! In recent months this AMD GPU back-end has received a lot of improvements from scheduler support and other new functionality.

- 64-bit ARM support. The 64-bit ARM / ARM64 / AArch64 support came after it was already brought to GCC, but now this next-generation ARM architecture has an LLVM back-end. ARM continues to grow in presence and 64-bit ARMv8 hardware should better compete against Intel/AMD x86 CPUs. With the new AArch64 target, there's C99 and C++03 support through Clang, Linux is currently the only platform target, and there's other basic functionality implemented at this time. Expect more AArch64 goodness to come in the next LLVM release.

- There's a new vectorizer! LLVM 3.3 brings forth the Superword-Level Parallelism (SLP) Vectorizer. There's already been some Phoronix benchmarks of the SLP vectorizer to mixed success. This new vectorizer is currently disabled by default. The SLP Vectorizer will be refined in future releases.

- LLVM's Loop Vectorizer has seen many improvements and is now enabled by default with the -O3 compiler switch. The 3.3 Loop Vectorizer improvements include being able to vectorize loops with unknown trip counts, runtime checks of pointers, if conversions, reverse iterators, vectorization of mixed types, vectorization of function calls, and much more. With this code vectorizer now being enabled by default, it's one of the reasons why for some workloads LLVM 3.3 is now much faster than LLVM 3.2.

- The Clang C/C++ compiler front-end is now C++11 feature-complete. GCC is also now effectively C++11 complete too, which is good news for developers wishing to take advantage of the latest C++ ISO standard. There's also already much work done on C++1y, the next revision to the standard.

- New CPU micro-architecture enhancements like better AVX2 support.

For benchmarks of LLVM/Clang 3.3, see this weekend's GCC 4.8.0 vs. LLVM Clang 3.3 Compiler Performance Three-Way from a Core i7 Sandy Bridge Extreme Edition, AMD FX-8350 Vishera, and Core i3 Ivy Bridge Ultrabook.

About The Author
Michael Larabel is the principal author of Phoronix.com and founded the web-site in 2004 with a focus on enriching the Linux hardware experience and being the largest web-site devoted to Linux hardware reviews, particularly for products relevant to Linux gamers and enthusiasts but also commonly reviewing servers/workstations and embedded Linux devices. Michael has written more than 10,000 articles covering the state of Linux hardware support, Linux performance, graphics hardware drivers, and other topics. Michael is also the lead developer of the Phoronix Test Suite, Phoromatic, and OpenBenchmarking.org automated testing software. He can be followed via and or contacted via .
Latest Linux Hardware Reviews
  1. MSI X99S SLI PLUS On Linux
  2. NVIDIA GeForce GTX 970 Offers Great Linux Performance
  3. CompuLab Intense-PC2: An Excellent, Fanless, Mini PC Powered By Intel's i7 Haswell
  4. From The Atom 330 To Haswell ULT: Intel Linux Performance Benchmarks
Latest Linux Articles
  1. Open-Source Radeon 2D Performance Is Better With Ubuntu 14.10
  2. RunAbove: A POWER8 Compute Cloud With Offerings Up To 176 Threads
  3. 6-Way Ubuntu 14.10 Linux Desktop Benchmarks
  4. Ubuntu 14.10 XMir System Compositor Benchmarks
Latest Linux News
  1. Dead Island GOTY Now Available On Linux/SteamOS
  2. Ubuntu 14.04 In The Power8 Cloud From RunAbove
  3. KDE With Theoretical Client-Side Decorations, Windows 10 Influence
  4. Sandusky Lee: Great Cabinets For Storing All Your Computer Gear
  5. Fedora 21 Beta & Final Release Slip Further
  6. Mesa 10.3.2 Has A Couple Bug-Fixes
  7. RadeonSI/R600g HyperZ Support Gets Turned Back On
  8. openSUSE Factory & Tumbleweed Are Merging
  9. More Fedora Delays: Fedora 21 Beta Slips
  10. Mono Brings C# To The Unreal Engine 4
Latest Forum Discussions
  1. HOPE: The Ease Of Python With The Speed Of C++
  2. Use Ubuntu MATE 14.10 Make it an official distro.
  3. Users/Developers Threatening Fork Of Debian GNU/Linux
  4. Debian Is Back To Discussing Init Systems, Freedom of Choice
  5. AMD Radeon VDPAU Video Performance With Gallium3D
  6. Updated and Optimized Ubuntu Free Graphics Drivers
  7. Ubuntu 16.04 Might Be The Distribution's Last 32-Bit Release
  8. Linux hacker compares Solaris kernel code: