== Last week (Linaro Connect) ==

* Reran libav comparisons after Ira's fix for excessive promotion.
  The vectorized versions are now at least as good as the non-vectorised
  ones.  Updated wiki page with new asm output and microbenchmark results.

* More work on SMS.  I have some patches that wire up the ddg code
  to IV analysis.  It gave some nice benchmark improvements, but also
  some regressions.  Traced the regressions down to cases where the
  schedule for small iis generated too many moves.  E.g. in a small
  microbenchmark, we were able to schedule 6 instructions with an
  ii of 3 (i.e. in a loop iteration of 3 cycles), but then needed
  to add ~9 moves in order to keep the dependencies correct.
  We got much better code with a larger ii and fewer moves.

  Wrote a patch to estimate how many moves would be added, and to try to
  a larger ii if the number of moves is too high.  This improved the
  results for one benchmark independently of the iv patch, and had no
  effect on the others.

  Discussed this with Revital, who said that Mustafa had tried a similar
  thing but seen no benefit.

* Got powerpc-ibm-aix5.3 bootstraps working.  Needs a few local fixes
  due to C++ bootstrapping.  Used it to test a couple of preparatory
  patches for the IV work.  Submitted those patches upstream.

* Ran benchmarks with -fno-schedule-insns after seeing that the first
  scheduling pass was responsible for the main NEON-vs.-non-NEON
  regression in EEMBC.  It fixed that case, but as expected,
  made others worse.  Mentioned this to Ramana, who pointed me at
  -fsched-pressure.

  Reran the benchmarks with -fsched-pressure instead of
  -fno-schedule-insns.  It too fixed the main regression,
  and improved a couple of other tests too.  It showed a regression
  in another test though.  Looked at that regression.  It was a case
  where many registers were live across a loop, but not used in it.
  This was causing the loop to have a very conservative schedule.
  It would be better to spill some of the other registers instead.

  Wrote a patch to take loops into account, and it seemed to do
  the right thing for EEMBC.  Sent it to Andreas, after Ulrich
  mentioned that he had been looking at -fsched-pressure problems
  on s390.  Andreas is away for a while, though, so I might put this
  on the back burner until he gets back.

== This week ==

* SMS

* auto inc/dec

* libav, perhaps

Richard

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