[Bug 1513985] Re: ffmpeg test idct8x8 (SIMPLE-ARM) fails on ARM32 when built with binutils from the trunk

[Launchpad Bug Tracker]

This bug was fixed in the package binutils - 2.25.51.20151113-1ubuntu1

---
binutils (2.25.51.20151113-1ubuntu1) xenial; urgency=medium

  * Merge with Debian; remaining changes:
- Build from upstream sources.
- Build binutils-static and binutils-static-udeb packages.
- Don't build cross binutils packages for Debian ports architectures.

binutils (2.25.51.20151113-1) unstable; urgency=medium

  * Snapshot, taken from the just created 2.26 branch (20151113).
- Fixed PR ld/19123. Closes: #801879.
- Ignore relocations in .data.rel.ro.local (hppa). Closes: #801531.
- Fix PR gas/19217, wrong use of MOVT to replace LDR (ARM32). LP: #1513985.
  * Stop building gold on sparc and sparc64. Closes: #803474.

 -- Matthias Klose   Fri, 13 Nov 2015 12:03:46 +0100

** Changed in: binutils (Ubuntu)
   Status: Confirmed => Fix Released

-- 
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
https://bugs.launchpad.net/bugs/1513985

Title:
  ffmpeg test idct8x8 (SIMPLE-ARM) fails on ARM32 when built with
  binutils from the trunk

To manage notifications about this bug go to:
https://bugs.launchpad.net/binutils/+bug/1513985/+subscriptions

-- 
ubuntu-bugs mailing list
ubuntu-bugs@lists.ubuntu.com
https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs

[Bug 1513985] Re: ffmpeg test idct8x8 (SIMPLE-ARM) fails on ARM32 when built with binutils from the trunk

[Andreas Cadhalpun]

A small clarification: the SIMPLE-ARM implementation can also be
selected at runtime, e.g. with the '-idct simplearm' option. That's
mainly useful for debugging purposes, though.

Regarding the binutils bug:
Attached testcase test.S doesn't require compiling ffmpeg, but simply:
$ gcc -g -c -o test.o test.S

Analyzing the difference of 'objdump -d test.o' between variants built
with working and broken binutils show that the working binutils always
always uses 'ldr.w' for ldr, while the broken version sometimes
optimizes this to 'movw', which is a correct alternative, but one time
to 'movt', which only sets half of the register.

** Attachment added: "testcase"
   
https://bugs.launchpad.net/ubuntu/+source/ffmpeg/+bug/1513985/+attachment/4516473/+files/test.S

-- 
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
https://bugs.launchpad.net/bugs/1513985

Title:
  ffmpeg test idct8x8 (SIMPLE-ARM) fails on ARM32 when built with
  binutils from the trunk

To manage notifications about this bug go to:
https://bugs.launchpad.net/binutils/+bug/1513985/+subscriptions

-- 
ubuntu-bugs mailing list
ubuntu-bugs@lists.ubuntu.com
https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs

[Bug 1513985] Re: ffmpeg test idct8x8 (SIMPLE-ARM) fails on ARM32 when built with binutils from the trunk

[Steve Langasek]

Correction to the title of this bug report: while the test output makes
it appear that the failing test is the last one (NEON), attempts to work
around this build failure by temporarily disabling NEON support in the
build revealed that it wasn't this test failing at all, but the test of
the SIMPLE-ARM implementation.

This is the implementation that Andreas pointed to in his comment, so it
appears debugging this is on the right track, but since I was confused
for a bit I thought I should set the record straight.

Also, since the SIMPLE-ARM implementation will never be used on any
Ubuntu architecture (it's superseded by either the NEON or the ARMV6
implementation on all armhf systems, which are by definition ARMv7 or
later), I have uploaded ffmpeg to simply disable the test of this dead
codepath at build time.

** Summary changed:

- ffmpeg test idct8x8 (NEON) fails on ARM32 when built with binutils from the 
trunk
+ ffmpeg test idct8x8 (SIMPLE-ARM) fails on ARM32 when built with binutils from 
the trunk

** Changed in: ffmpeg (Ubuntu)
   Status: New => Fix Released

-- 
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
https://bugs.launchpad.net/bugs/1513985

Title:
  ffmpeg test idct8x8 (SIMPLE-ARM) fails on ARM32 when built with
  binutils from the trunk

To manage notifications about this bug go to:
https://bugs.launchpad.net/binutils/+bug/1513985/+subscriptions

-- 
ubuntu-bugs mailing list
ubuntu-bugs@lists.ubuntu.com
https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs