Tuesday 2nd April 2013

This month's meetings

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  • Matthew Gretton-Dann
  • James Elliott

GCC Team

  • Christophe Lyon
  • Yvan Roux
  • Venkat Kumar (Absent - left status by email)
  • Kugan Vivekarandarajah
  • (Zhenqiang Chen on vacation - left status by Email)

LLVM + Libs & Dev Tools:-

  • (Renato Golin - left status by Email)
  • Will Newton
  • Mans Rullgard (absent - on Vacation)
  • Omair Javaid (absent - left status by email)
  • Peter Maydel (absent - left status by email)l

From ARM:-

  • Richard Earnshaw
  • Ramana Radhakrishnan


  • Review activity last week
  • Discuss plans for coming week
  • Raise any issues holding up progress

Action Items from this Meeting

  • [Matt / Christophe] Discuss Cbuild disk full cleanup

Action Items from Previous Meeting

  • TBA


GCC Team



  • Disable-peeling:
    • - benchmarked locally on snowball. Observed a few regressions in spec2k.
      • To be analyzed and confirmed with the results from cbuild.
      - patched cbuild to work-around a bzr bug which prevented these jobs from being spawned.
  • Libsanitizer: sent patch upstream.
    • Discussion about interactions with qemu.
  • Revert-coalesce: spawned thought-to-be reference jobs for benchmarking.
  • Neon intrinsics codegen:
    • - First analysis of sample codecs seems to indicate that gcc generates sequences of interdependent instructions where rvct manages to insert some code in between. - To be confirmed by dedicated benchmarking, probably in bare-machine mode.
  • Neon intrinsics testsuite:
    • - Added support for polynomial variants (*_p8, *_p16) - Identified wrong code generated by gcc-linaro-4.7; did not check with trunk.

      - Transforming into a dejagnu forms will probably be a lot of work :-(

  • Internal activities


  • Disable-peeling:
    • - analyze bench results from cbuild when available - compare with the results from my snowball
  • Libsanitizer:
    • - resume investigation about isatty problem when ran under qemu.
  • Turnoff 64bits ops In Neon:
    • - backport in linaro-4.8 once the process has been clarified.
  • Revert-coalesce:
    • - check bench results
  • Neon intrinsics codegen:
    • - perform dedicated benchmarking



  • Libunwind AArch64 support:
    • - Most of the testsuite is now fine - but some fixes still needed before upstream submission.


  • Libunwind AArch64 support:
    • - Fix and submit upstream.


  • None



- Very short work week. I was on leave last Wednesday and Thursday (27th and 28th). - Posted patch for gc-section tests for TLS and got related relocs. - Discussing with Marcus on patch I wrote for gc section tests on PLT related relocs.


- Post patch for gc section tests for PLT relocs. - Complete gc section tests for other generic cases. - Understand and evaluate gprof support work for Aarch64



working on http://cards.linaro.org/browse/TCWG-14 - All but 2 test cases are passing and extension elimination for the simple cases are eliminated - one of the test failure was due to bug with value range propagation pass. Have to investigate this further. - In one instance even though extensions are removed, 1 more instruction is generated (for crc) - Need to investigate it - Got the chromebook and Set up Ubuntu; boot strapping gcc now


- Start with the benchmarking - investigate the performance and VRP issue - Also start with http://cards.linaro.org/browse/TCWG-13 in parallel

Zhenqiang Chen


  • Investigate how to expand conditional compare.


1. Try to expand conditional compare to RTL

  • It seams hard to expand conditional compare to just one cond_exec insn during expand, since it has to know the cc (GT, LT, etc) set from previous instruction and tell the later instruction which cc (GT, LT, etc) it set.
  • Try to add new RTL key-word and insn pattern.

2. Follow up Linaro toolchain binaries bug in Yocto build: 1159392, 1161348 and 1161351.


  • Generate asm for conditional compare.


Planned leaves:

  • April 4-8: Chinese Ching Ming Festival and annual leaves.
  • April 12: Internal team event.
  • April 16-17: Internal training.




  • Re-installed the panda buildbot, using USB drive as bot dir
  • Reviewing lots of ARM patches (more than usual)
  • Trying Arndale again, some errors, some passes, cooler might be responsible - Got one internal error, one build error and one pass with Ubuntu kernel

+ patch

  • - Trying Suse image:
    • - It has a broken serial driver (makes things much harder) - sshd does not start by default (in conjunction with serial bug, it's a killer) - Now running on a precarious mode, hopefully enough for our needs
  • sqlite3 error due to VMUL.f64 while on x86_64 "long double" is f128
    • - sqlite3 is the best example on what NEVER to do with floating point values >:| - Sent patch, working around TILE-Gx issues


  • Still a bit ill, productivity reduced
  • Not having a wired network on my desk wastes a LOT of my time


  • Push the sqlite3 patch though
  • Continue fixing the 4 remaining broken tests
  • Continue with Arndale investigation with Christophe and Zhenqiang


Will Newton


  • Booked flight for LCE.
  • Benchmarked and ran tests on new memcpy implementation.
  • Attempted but failed to get new memcpy tested on big endian (still todo).
  • Committed new memcpy implementation to cortex strings.
  • Passed new memcpy to Android team for bionic.
  • Submitted newlib patch for new memcpy.
  • Committed binutils ld-elfvsb testsuite fixes, native testsuite now green!
  • Further investigation of IFUNC in glibc.


  • Pandaboard ES still a bit flakey, Chromebook hopefully on its way to replace it.


  • Iron out issues with native binutils make check in cbuild/LAVA.
  • Get newlib memcpy patch committed.
  • Investigate testing memcpy on big endian (qemu user, models?).
  • IFUNC...



  • qemu maintenance
  • * https://ci.linaro.org/jenkins/job/qemu-ltp/ now shows graphs

    • of LTP test results for linux-user mode
  • * rebased qemu-linaro and got it working again (omap3 display
    • code needed rework after upstream changes)
  • * investigated why Christoffer Dall's kernels weren't booting:
    • turns out to be that vexpress now requires CONFIG_REGULATOR but doesn't force it to be set or set it in the vexpress_defconfig
  • * rebased/resent/pinged various in-flight patches
  • VIRT-4 [Guest migration support for KVM]
  • * VIRT-49: implement cp15 sync with kernel
  • ** located my work on this from last year, refreshed my
    • memory on how far I'd got and what I was planning to do

-- PMM

WorkingGroups/ToolChain/Meetings/Archive/2013-04-02 (last modified 2013-08-30 11:49:35)