- linaro-toolchain - lists.linaro.org

Linaro GDB 7.3 2011.10 released

by Ulrich Weigand

The Linaro Toolchain Working Group is pleased to announce the release of Linaro GDB 7.3. Linaro GDB 7.3 2011.10 is the third release in the 7.3 series. Based off the latest GDB 7.3, it includes a number of ARM-focused bug fixes and enhancements. This release contains: * Support for disabling address space randomization in gdbserver * Fix for GDB crashes on 3.x kernels * Fix spurious "CRC mismatch" warnings when using "remote:" sysroot The source tarball is available at: https://launchpad.net/gdb-linaro/+milestone/7.3-2011.10 More information on Linaro GDB is available at: https://launchpad.net/gdb-linaro

14 years, 7 months

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[ACTIVITY] October 9-12

by Ira Rosen

Hi, * Finished a presentation for NEON forum. Revital and Richard kindly agreed to take a look and gave me some valuable comments. Thanks! * widen-shifts: - While preparing the presentation I found some room for improvement in the pattern detection, so I implemented it. It gave additional 13% to rgb24tobgr16. - Ramana suggested a solution on how to check the constant operand of vshll. Testing these two things on ARM. * SLP improvements: - Implemented a patch that swaps operands if necessary to make the operations isomorphic, and supports loads with different offsets. Testing it now. - The three relevant libav loops now get vectorized giving 42%-57% speedup. Next week holidays: half days Sunday-Wednesday and Thursday. Ira

14 years, 7 months

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Binary toolchain questions summary

by Michael Hope

Here's my summary from Monday's meeting on the harder parts of binary toolchains. Using a 4.6 compiler against a 4.5 based sysroot such as Natty: * libgcc and libstdc++ are part of the compiler * The compiler expects features that are in the corresponding runtime * You can't reliably run or validate against an earlier runtime The solution is to upgrade the runtime on the sysroot to 4.6. 4.6 is backwards compatible. Ubuntu did this with Maverick and it caused no problems, although problems such as Debian #622783 have been seen. Multiarch: * The Ubuntu multiarch patch should work with a sysroot * Multiarch and multilib should work together Multilib: * The current ARM multilib rules are old and not very relevant * Multilib means you need multiple sysroots as well * Skip multilib for the first release Other: * Anything we support in cross we should support native first * Check that we don't have to directly supply the source that goes with the binary sysroot -- Michael

14 years, 7 months

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How to install an ARM cross compiler

by Andrew Stubbs

Saw this, thought it might be interesting if we want to point people at it something in future .... http://playterm.org/r/install-an-arm-cross-compiler-1316950150 Maybe we could record some more detailed stuff ourselves? Andrew

14 years, 7 months

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[Activity] Week ending 7th Oct. 2011

by Ramana Radhakrishnan

==Progress=== * Out of office for a day. * Wrote a quick patch to do vcvt.f32.s32 with fractional bits where we can. Tested no regressions, need to commit this after review upstream. * Desk move and packing for that. * Looked at a bug report LP 836588 appears to go away with fno-gcse. Needs more digging. === Plans === * Look at LP 836588. * Finish auto-inc-dec pipeline scheduling work. * Clear out some of the old patches (POST_MODIFY_DISP for vfp, BRANCH_COST ) * Settle into new desk. * Again a short week as I'm away for 2 days for an internal training event. Meetings: * 1-1s * TCWG calls Absences. * 5th October - out of office. * 13th - 14th October - Out of Office - Internal training event. * 31st Oct - 4th Nov - Linaro Summit Orlando - Travel booked - * 08 Nov - 11 Nov - Tentatively booked * Dec 19 - 31st Dec - Tentatively booked

14 years, 7 months

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[ACTIVITY] Weekly status

by Richard Sandiford

== Last week == * Patch review. * Backported second attempt to fix get_arm_condition_code ICE. * Worked on -fsched-pressure. Experimented with various combinations of ideas. This is giving some good results (e.g. a 2x improvement in libav's put_h264_qpel8_hv_lowpass_8) but needs a bit more work to fix some outliers. I'll be away from 18th Oct to 14th Nov. Richard

14 years, 7 months

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Native build performance

by Michael Hope

Random data for the day: Dave Pigott has installed some new PandaBoard build machines in the validation lab. They're identical to mine except that root is on USB Flash instead of NFS, and they have a much faster flash drive for the build area. The time taken to bootstrap and test gcc-linaro-2011.09 with C, C++, Fortran, and LTO is: * ursa3, ursa4 (Toshiba USB stick): 301 minutes build / 369 test * ursa2 (no-name USB stick): 324 minutes build / 422 test * tcpanda (fast USB stick): 274 minutes build / 265 test So the new combo gives a 1.38 x faster build. I'm surprised as I though the build was CPU bound. I'd hate to see what building on an SD card is like. Note that /tmp is in RAM, /scratch is ext4, the new boards use noatime, and the kernel doesn't have the new USB performance fix. -- Michael

14 years, 7 months

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[ACTIVITY] weekly status

by Revital Eres

Continue working on estimating register pressure with SMS: - Discussed current approach with Richard which gave useful leads. - Started to implement this approach. - Doing experiments on libav microbench.

14 years, 7 months

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Re: Use of memcpy() in libpng

by jbowler＠acm.org

The unaligned accesses in libpng are, for the large copies, a bug. Our attempt to align the row buffer to a 16 byte boundary was off-by-one so we end up always mis-aligning it. I've posted a patch on the png-mng-implement list: http://sourceforge.net/mailarchive/message.php?msg_id=28194444 The time spent in memcpy() is probably an illusion. The data out of zlib gets copied to one row buffer where it is unfiltered (if necessary) then a copy is made in a separate buffer that is only used for the filter handling. If you test using images with large rows (I don't know what pngbench does) the copy buffer may well get flushed out of the second level cache between each row, then the memcpy will stall bringing it back in. If you have machine level profiling you may see this as a massive time spike on some probably unrelated instruction which just happens to be in the PC when the stall stops everything. Anyway, I have several ideas of how to avoid the copy when it isn't required. John Bowler <jbowler(a)acm.org> -----Original Message----- From: Glenn Randers-Pehrson [mailto:glennrp@gmail.com] Sent: Monday, October 03, 2011 1:15 PM To: PNG/MNG implementation discussion list Subject: [png-mng-implement] Use of memcpy() in libpng [Fwd from linaro-toolchain list] Re: Use of memcpy() in libpng David Gilbert Tue, 27 Sep 2011 06:20:14 -0700 On 27 September 2011 14:16, Christian Robottom Reis <k...(a)linaro.org> wrote: > On Tue, Sep 27, 2011 at 09:47:33AM +0100, Ramana Radhakrishnan wrote: >> On 26 September 2011 21:51, Michael Hope <michael.h...(a)linaro.org> wrote: >> > Saw this on the linaro-multimedia list: >> > >> > http://lists.linaro.org/pipermail/linaro-multimedia/2011-September/ >> > 000074.html >> > >> > libpng spends a significant amount of time in memcpy(). This might >> > tie in with Ramana's investigation or the unaligned access work by >> > allowing more memcpy()s to be inlined. >> >> It's the unaligned access and the change / improvements to the memcpy >> that *might* help in this case. But that ofcourse depends on the >> compiler knowing when it can do such a thing. Ofcourse what might be >> more interesting is the kind of workload analysis that Dave's done in >> the past with memcpy to know what the alignment and size of the >> buffer being copied is. > > If you guys could take a look at this there is a potential requirement > for the MMWG around libpng optimization; we could fit this in along > with other work (possible vectorizing, etc) on that component. It wouldn't take long to analyse the memcpy calls - life would be easier if we had the test program and some details on things like what size of images were used in these benchmarks. Dave

14 years, 7 months

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[ACTIVITY] 3rd - 7th October

by Andrew Stubbs

Continued work on my constant reuse optimizations. Not too much this week though. I've now fixed some issues with the ARM size-costs code that was causing it to wildly over-estimate the cost of a MOVT instruction. I'll have to post this upstream sometime soon. Took another look at the shift-amount bug. Discussed the issue with Paul Brook. I've now fixed the original bug, and fixed the new bug introduced by Paul's original fix, and committed that upstream. I still need to backport it to Linaro GCC though, and the latent bug that Richard S spotted is still being analysed. Did a merge from FSF 4.5 & 4.6 to Linaro, and pushed them the Launchpad branches for testing. Begun work benchmarking different setups for the generic tuning patches. I had a lot of trouble trying to set up SPEC2000 though. Hopefully these issues are now resolved, with some help from Michael, and I have established some baseline figures on both A8 and A9 to work from. No progress on native tuning. I'm still waiting for upstream review. In other news: Mentor's contract with Linaro has now been extended for another 6 months. :)

14 years, 7 months

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[ACTIVITY] 2011-10-07

by David Gilbert

== String Routines == * Built and tested a newlib with my memchr in - ready to go with a bit of tidy up. * Followed up on my eglibc patch submission by a comment suggesting the use of --with-cpu pointing back at the previous discussion. == 64 Bit atomics == * Updated gcc patch based on Ramana's comments, retested and posted new version - Lost half a day to a failing SD card in our panda. == QEMU == * Posted a patch that made one variable thread local using __thread that fixes multi threaded user mode ARM programs (e.g. firefox); this seems to have mutated on the list into a patch for more general thread local support. Dave

14 years, 7 months

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[ACTIVITY] Oct 04 - Oct 07

by Ulrich Weigand

== GDB == * Reimplemented patch to disable address space randomization in gdbserver to respect the "set disable-randomization" command, and checked it in to mainline and Linaro GDB 7.3 * Worked on support for cross-platform core file generation. == GCC == * Checked in mainline fix for PR 50305. Mit freundlichen Gruessen / Best Regards Ulrich Weigand -- Dr. Ulrich Weigand | Phone: +49-7031/16-3727 STSM, GNU compiler and toolchain for Linux on System z and Cell/B.E. IBM Deutschland Research & Development GmbH Vorsitzender des Aufsichtsrats: Martin Jetter | Geschäftsführung: Dirk Wittkopp Sitz der Gesellschaft: Böblingen | Registergericht: Amtsgericht Stuttgart, HRB 243294

14 years, 7 months

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[ACTIVITY] October 2-6

by Ira Rosen

Hi, - worked on the RTL part of the widen-shift patch - backported to linaro 2/3 of the SLP patches, and proposed the third one - worked on additional SLP improvements: - swap operands to make statements isomorphic - support load with offset 1 (after load from 0) - started working on presentation for NEON forum Upcoming holidays: Oct 12, Wed - half day Oct 13, Thu Oct 16-19, Sun-Wed - half day Oct 20, Thu Ira

14 years, 7 months

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[RFC ARM] Use vcvt.f32.s32 with immediate bits to do fixed to floating point conversions.

by Ramana Radhakrishnan

Hi, So one of the things Michael pointed out in today's call was that the ARM backend doesn't generate vcvt.f32.s<type> where you have an idiom conversion from fixed to floating point as in the example below. I've chosen to implement this in the following manner in the backend using these interfaces from real.c . The reason I've chosen to not allow this transformation in case flag_rounding_math is true is because this instruction always ends up rounding using round-to-nearest rather than obeying whats in the FPSCR and thus is not safe for programs that want to dynamically set their rounding modes. The benefits are quite obvious in that we eliminate a load from the constant pool and a floating point multiply and thus essentially shaving off a floating point multiply + Load latency off these sequences. This instruction can only write the output into the same register as the input register which is why I've modelled it as below by tying op1 into op0. If there's a simpler way of using the interfaces into real.c then I'm all ears ? Thoughts ? I believe such idioms are used in libav from where the original report appears to have come and thus it's a worthwhile gain where we can have it. Any other places where folks might have noticed this. I will post upstream as well once I finish testing this patch. I'm posting this here to get some feedback as well to let anyone who is really really keen about trying this out have a go given I'm out tomorrow. ( I took a quick look at the short -> f32 case as well but the fact remains that loads either zero or sign extend anyway so there's probably not much gain in modelling that right away and the win really is in getting rid of that fp mul and the constant pool load. There's probably some gain in going from i64-> f64 as well so those patterns need to be written up at some point for completeness ) cheers Ramana 2011-10-04 Ramana Radhakrishnan <ramana.radhakrishnan(a)linaro.org> * config/arm/arm.c (vfp3_const_double_for_fract_bits): Define. * config/arm/arm-protos.h (vfp3_const_double_for_fract_bits): Declare. * config/arm/constraints.md ("Dt"): New constraint. * config/arm/predicates.md (const_double_vcvt_power_of_two_reciprocal): New. * config/arm/vfp.md (*arm_combine_vcvt_f32_s32): New. (*arm_combine_vcvt_f32_u32): New. For the following testcases I see the code as follows with -mfloat-abi=hard -mfpu=vfpv3 and -mcpu=cortex-a9 float foo (int i) { float v = (float)i / (1 << 11); return v; } float foa_unsigned (unsigned int i) { float v = (float)i / (1 << 5); return v; } After patch . foo: @ args = 0, pretend = 0, frame = 0 @ frame_needed = 0, uses_anonymous_args = 0 @ link register save eliminated. fmsr s0, r0 @ int vcvt.f32.s32 s0, s0, #11 bx lr .size foo, .-foo .align 2 .global foa_unsigned .type foa_unsigned, %function foa_unsigned: @ args = 0, pretend = 0, frame = 0 @ frame_needed = 0, uses_anonymous_args = 0 @ link register save eliminated. fmsr s0, r0 @ int vcvt.f32.u32 s0, s0, #5 bx lr .size foa_unsigned, .-foa_unsigned .align 2 .global foo1 .type foo1, %function rather than .type foo, %function foo: @ args = 0, pretend = 0, frame = 0 @ frame_needed = 0, uses_anonymous_args = 0 @ link register save eliminated. fmsr s15, r0 @ int fsitos s0, s15 flds s15, .L2 fmuls s0, s0, s15 bx lr .L3: .align 2 .L2: .word 973078528 .size foo, .-foo .align 2 .global foa_unsigned .type foa_unsigned, %function foa_unsigned: @ args = 0, pretend = 0, frame = 0 @ frame_needed = 0, uses_anonymous_args = 0 @ link register save eliminated. fmsr s15, r0 @ int fuitos s0, s15 flds s15, .L5 fmuls s0, s0, s15 bx lr .L6: .align 2 .L5: .word 1023410176

14 years, 7 months

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[ACTIVITY] 26th - 30th September

by Andrew Stubbs

* Vacation Monday, Tuesday, and Wednesday. * GCC Continued work on my constant reuse optimizations. Disappointingly, I've found that there are very few optimization opportunities in EEMBC (ARM/Thumb V7-A), although it's not difficult to write testcases that the optimization could improve. I also discovered that the data-flow chains don't work exactly how I thought (with respect to if-then-else cases) so I need to do a little more work. Pinged the native tuning patches; they're still waiting for upstream review. Still can't get the generic tuning work done as the CodeSourcery panda boards appear to be still offline.

14 years, 7 months

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[ACTIVITY] Weekly status

by Revital Eres

Committed to mainline the patch to support instructions with auto-inc operations in SMS after addressing Ayal's comments. The patch contains two parts; one of them fixes a bug revealed during bootstrapping with the patch and SMS flags. http://gcc.gnu.org/ml/gcc-patches/2011-09/msg01988.html http://gcc.gnu.org/ml/gcc-patches/2011-09/msg01987.html Looking at estimating register pressure with SMS: based on previous discussion with Richard the current approach is to try and use the register pressure estimation in loop invariant pass.

14 years, 7 months

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undefined reference to __aeabi_unwind_cpp_pr0

by AJ ONeal

I'm compiling an application built with TI's DVSDK 3 *[0]. /home/user/ti/dvsdk/dvsdk_3_01_00_10/linuxutils_2_25_02_08/packages/ti/sdo/linuxutils/cmem/lib/cmem.a470MV(cmem.o470MV):(.ARM.exidx+0x0): undefined reference to `__aeabi_unwind_cpp_pr0' arm-linux-gnueabi-gcc --version arm-linux-gnueabi-gcc (Ubuntu/Linaro 4.5.2-5ubuntu2~ppa1) 4.5.2 arm-linux-gnueabi-ld --version GNU ld (GNU Binutils for Ubuntu) 2.21.0.20110302 More full output is here (but it isn't particularly helpful due to TI's RTSC make system's black-magic) https://gist.github.com/925674 FYI: the MV in cmem.a470MV stands for MontaVista. This name is hard-coded somewhere even though it's not being linked against a MontaVista system. I believe the 470 means that it should work with ARMv4 through ARMv7, but I'm not positive. My googling suggest that this is a toolchain bug and that the best way around the issue is to create a file which defines the function as a void dummy and include it. http://www.codesourcery.com/archives/arm-gnu/msg03604.html http://comments.gmane.org/gmane.comp.boot-loaders.u-boot/78649 http://www.cs.fsu.edu/~baker/devices/lxr/http/ident?i=__aeabi_unwind_cpp_pr0 I have a script that I'll post shortly with instructions as to how to setup TI's DVSDK with Linaro AJ ONeal [0] I'm not using the latest DVSDK version 4 because the paths and such are so hard-coded for the 2009q3 version of codesourcery on ubuntu 10.04 LTS that I don't know where to start fixing it.

14 years, 7 months

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[ACTIVITY] Week ending 30th September 2011.

by Ramana Radhakrishnan

===Progress=== * Patch review week. * Looked at bootstrap issue for a while but Richard Sandiford picked it up and sorted it out (Thanks Richard). * Fun and games with some paperwork. * Some backporting and testing patches. (50099 and 50186) underway. === Plans === * Clear out some of the old patches (POST_MODIFY_DISP for vfp, BRANCH_COST ) and finish on auto-inc-dec patch from last week. * Away for 1 day next week. Meetings: * 1-1s * TCWG calls Absences. * 5th October -Out of Office. * 13th - 14th October - Internal training. * 31st Oct - 4th Nov - Linaro Summit Orlando. * 08 Nov - 11 Nov - Tentatively booked * Dec 19 - 31st Dec - Tentatively booked

14 years, 7 months

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[ACTIVITY] report week 39

by Peter Maydell

(short week: 3 days) RAG: Red: Amber: Green: Current Milestones: || || Planned || Estimate || Actual || ||add-omap3-networking || 2011-10-13 || 2011-10-13 || || ||a15-systemmode-planning || 2011-10-13 || 2011-10-13 || 2011-09-22 || ||a15-usermode-support || 2011-11-10 || 2011-11-10 || || ||upstream-omap3-cleanup || 2011-11-10 || 2011-11-10 || || Historical Milestones: ||qemu-linaro 2011-04 || 2011-04-21 || 2011-04-21 || 2011-04-21 || ||qemu-linaro 2011-05 || 2011-05-19 || 2011-05-19 || n/a || ||close out 1105 blueprints || 2011-05-28 || 2011-05-28 || 2011-05-19 || ||complete 1111 planning || 2011-05-28 || 2011-05-28 || 2011-05-27 || ||qemu-linaro-2011-06 || 2011-06-16 || 2011-06-16 || 2011-06-16 || ||qemu-linaro-2011-07 || 2011-07-21 || 2011-07-21 || 2011-07-21 || ||qemu-linaro 2011-08 || 2011-08-18 || 2011-08-18 || 2011-08-18 || ||qemu-linaro 2011-09 || 2011-09-15 || 2011-09-15 || 2011-09-15 || == a15-usermode-support == * completed the implementation and testing of fused-mac instructions; posted patch series with these and udiv/sdiv == other == * lightning talk for pdsw doughnut session Current qemu patch status is tracked here: https://wiki.linaro.org/PeterMaydell/QemuPatchStatus

14 years, 7 months

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[ACTIVITY] Weekly status

by Richard Sandiford

== This week == * Applied patch for doing NEON high/low extraction using subregs. Ramana pointed out that we do the same thing for insertion, so I wrote a patch to handle that too. Both now merged into Linaro sources. * Looked at ARM bootstrap problem on trunk. Turned out to be an aliasing problem. Submitted and applied patch. * Reworked part of my SMS register-scheduling patch after feedback from Ayal. Submitted new version upstream. * Got SPEC2006 running on the powerpc boxes and tested one part of my -fsched-pressure patch. Bit of a mixed bag. h264ref was one of the worst sufferers, which was a bit worrying. I think I'll need to make a third change too. To recap, there are two pieces now: 1) Make -fsched-pressure honour the DFA 2) Make -fsched-pressure allow values that are live across a loop to be spilled. I naively hoped that (1) would be OK on its own, but h264 shows that the current -fsched-pressure code is very conservative when it comes to large blocks. It only considers register deaths once there is a single remaining use; if there are two unscheduled uses, it assumes that the register remains live for the rest of the block. So the problem that (1) was fixing was that -fsched-pressure was too optimistic in terms of what it could schedule in a cycle. But with that fixed, we seem to have too many sources of pessimism... Richard

14 years, 7 months

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[ACTIVITY] Sep 26 - Sep 30

by Ulrich Weigand

== GDB == * Worked on support for cross-platform core file generation. * Followed up on patch to support disabling address space randomization in gdbserver. == GCC == * Followed up on patch for PR 50305. Mit freundlichen Gruessen / Best Regards Ulrich Weigand -- Dr. Ulrich Weigand | Phone: +49-7031/16-3727 STSM, GNU compiler and toolchain for Linux on System z and Cell/B.E. IBM Deutschland Research & Development GmbH Vorsitzender des Aufsichtsrats: Martin Jetter | Geschäftsführung: Dirk Wittkopp Sitz der Gesellschaft: Böblingen | Registergericht: Amtsgericht Stuttgart, HRB 243294

14 years, 7 months

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[ACTIVITY] w39

by Asa Sandahl

* Working on croos-compiling Firefox. Getting dependencies in place and setting up the configuration file (.mozconfig). I have had the strategy to fix one dependency at a time, picking prebuilt packages or building my self. Michael told me at yesterday's meeting about multistrap, that could possibly be used for fixing all dependencies at once. I will look into that next week. * During this process I have also spent some time reading up on cross compilation in general and also on autoconf and the GNU build system. Best Regards Åsa

14 years, 7 months

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[ACTIVITY] 2011-09-28

by David Gilbert

== String routines == * Got eglibc testing setup happy at last - Note that -O3 builds generally seem to give a few more errors that are probably worth looking at - -march=armv6 -mthumb hit some non-thumb1 instructions (normally non-lo registers), again worth looking at - Cross testing to Qemu user mode often stalls, mostly on nptl tests that abort/fail when run in system/natively * Sent new version of eglibc/memchr patch upstream * Now have working newlib test setup and reference set - next step is to try adding my memchr there == Other == * Testing a QEmu patch with Peter * Looking at bug 861296 (difference in mmap layouts) * Adding a few suggestions to the set of cpu hotplug tests. * Dealing with the Manchester lab cold. Short week; back on Monday Dave

14 years, 7 months

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[ACTIVITY] September 25-28

by Ira Rosen

Hi, * change default vector size patch - merged to linaro-gcc * SLP improvements committed upstream: - allow not affine accesses - auto-detect vector size - support multiple types and promotion/demotion operations Ira

14 years, 7 months

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[ACTIVITY] Sep 19 - Sep 23

by Ulrich Weigand

== GDB == * Committed hardware watchpoint support for gdbserver to mainline, including two minor changes resulting from review comments; backported those fixes to Linaro GDB as well. * Implemented and tested support for disabling address space randomization in gdbserver; patch posted for review. * Investigated support for cross-platform core file generation. == GCC == * Patch review week. * Posted updated patch for PR 50305. Mit freundlichen Gruessen / Best Regards Ulrich Weigand -- Dr. Ulrich Weigand | Phone: +49-7031/16-3727 STSM, GNU compiler and toolchain for Linux on System z and Cell/B.E. IBM Deutschland Research & Development GmbH Vorsitzender des Aufsichtsrats: Martin Jetter | Geschäftsführung: Dirk Wittkopp Sitz der Gesellschaft: Böblingen | Registergericht: Amtsgericht Stuttgart, HRB 243294

14 years, 7 months

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