[Ubuntu 16.04.1] gcc 5: additional swap optimizations for POWER8

[bugproxy]

There have been a number of recent changes to enhance swap optimization for POWER8, which improves performance on some vector codes. These changes have been applied in a single patch to the upstream ibm/gcc-5-branch in r233957. I would like to request that this patch be applied to GCC 5 in the 16.04.1 Ubuntu release.

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[Steve Langasek (vorlon)]

Matthias, please evaluate this request from IBM for a toolchain change for Power. Is this a reasonable enhancement for us to take either before release or in the point release? What criteria would we use in assessing the change's impact on the distribution?

[Matthias Klose (doko)]

please could you merge the gcc-5-branch into ibm/gcc-5-branch, and check for test regressions before we build from the updated ibm/gcc-5-branch?

[bugproxy (bugproxy)]

------- Comment From <email address hidden> 2016-03-10 08:50 EDT-------
Sure, we'll be happy to do that. When would be the best time for us to do the merge to mesh well with your schedules?

[Matthias Klose (doko)]

if the tests don't show regressions, I'm fine to include these changes next week, targeting the 16.04 LTS release.

[bugproxy (bugproxy)]

------- Comment From <email address hidden> 2016-03-10 10:06 EDT-------
OK, great. I did test for regressions without a merge, although we had a pretty recent merge before that, so I'm pretty comfortable with it. We'll do another merge and check things are still ok. Thanks!

[bugproxy (bugproxy)]

------- Comment From <email address hidden> 2016-03-10 12:42 EDT-------
Hi doko,

Peter Bergner has committed the merge and reports no new regressions. So this should be ready to go. Thanks for your flexibility!

Bill

[Matthias Klose (doko)]

fixed in 5.3.1-11ubuntu1