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

Unpleasant: LLVM/Clang 3.2 On The ARM Cortex-A15

Compiler

Published on 30 December 2012 05:08 AM EST
Written by Michael Larabel in Compiler
5 Comments

Since publishing LLVM/Clang 3.2 benchmarks a few days ago that showed the Clang C/C++ compiler competing with -- and in some cases outperforming -- the GCC compiler on Intel x86_64, several Phoronix readers have been asking how things compare on the ARM side.

While a few weeks back I published some early benchmarks of GCC vs. LLVM/Clang on the ARM Cortex-A15 using the Samsung Google Chromebook with the Exynos 5 Dual, it seems since the LLVM/Clang 3.0 release, there's some ARMv7 regressions that have come up.

After building the final release of LLVM/Clang 3.2 in the same way to previous LLVM/Clang releases on the same hardware and in a similar manner to other ARM Cotex-A9 development boards, I've been hitting some pain points. With the Samsung Exynos 5 Dual's ARM Cortex-A15, I'm now hitting new problems with LLVM/Clang 3.2 not encountered on the A9 hardware tested. Segmentation faults in Clang have become common in this latest A15 compiler testing on Linux:
4. Running pass 'ARM Instruction Selection' on function '@__cxx_global_var_init'
clang: error: unable to execute command: Segmentation fault (core dumped)
clang: error: clang frontend command failed due to signal (use -v to see invocation)
clang version 3.2 (tags/RELEASE_32/final)
Target: armv7l-unknown-linux-gnueabihf
Thread model: posix
clang: note: diagnostic msg: PLEASE submit a bug report to http://llvm.org/bugs/ and include the crash backtrace, preprocessed source, and associated run script.
clang: note: diagnostic msg:
********************
PLEASE ATTACH THE FOLLOWING FILES TO THE BUG REPORT:
Preprocessed source(s) and associated run script(s) are located at:
clang: note: diagnostic msg: /tmp/smallpt-z07Dod.cpp
clang: note: diagnostic msg: /tmp/smallpt-z07Dod.sh
clang: note: diagnostic msg:
********************
The Clang segmentation faults have been common within the ARM Instruction Selection pass on this release that came out last week and has occurred for multiple test profiles on different functions. This A15 upset is sad to see with the ARM Cortex-A15 performance being a huge upgrade over the A9-based ARM SoCs.

LLVM 3.2 brought many new features, including on the ARM side, but unfortunately not without some fallout. LLVM/Clang 3.2 benchmarks from ARM Cortex-A9 hardware is forthcoming while it's likely that the Cortex-A15 benchmarks will be delayed to the next release unless a workaround/fix is soon discovered.

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. Intel Xeon E5-1680 v3 & E5-2687W v3 Compared To The Core i7 5960X On Linux
  2. Intel 120GB 530 Series SSD Linux Performance
  3. Btrfs/EXT4/XFS/F2FS RAID 0/1/5/6/10 Linux Benchmarks On Four SSDs
  4. AMD's Windows Catalyst Driver Remains Largely Faster Than Linux Drivers
Latest Linux Articles
  1. Mesa Git Yields Performance Improvements For Newer AMD GPUs
  2. Apple OS X 10.10 vs. Ubuntu 14.10 Performance
  3. Mesa 10.5-devel Brings Some Intel Haswell HD Graphics Changes Over Mesa 10.3
  4. NVIDIA vs. Nouveau Drivers With Linux 3.18 + Mesa 10.4-devel
Latest Linux News
  1. Qt 5.4 Planned For Release On 9 December
  2. Meizu's Ubuntu Phone Not Expected Until Early Next Year
  3. DragonFlyBSD 4.0 Drops i386 Support, Improves Graphics
  4. Expensive "Free/Libre Software Laptop" Uses A NVIDIA GPU
  5. QEMU 2.2-rc3 Released, Final Release Pushed Back By Couple Days
  6. 64-bit ARM FreeBSD Support Is Taking Shape
  7. GCW Zero Starts Seeing New Game Releases
  8. Intel's Cherry Trail Delayed To Next Year
  9. Bq Introduces More Android Devices, But Still No Ubuntu Phones
  10. Qt 5.4 Release Candidate Expected Later This Week
Latest Forum Discussions
  1. Updated and Optimized Ubuntu Free Graphics Drivers
  2. Hurrican SDL Port
  3. Roadmap to Catalyst 14.10 ?
  4. how to configure module phoromatic ?
  5. PulseAudio 6.0 Is Coming & Other Linux Audio Plans For The Future
  6. Debian Developer Resigns From The Systemd Maintainership Team
  7. Cant get working Kaveri APU - A10-7850k
  8. Script for Fan Speed Control