[Qemu-devel] [PATCH v2 for-2.5 00/12] tcg: improve optimizer

[Aurelien Jarno]

This patchset improves the optimizer in 3 different ways:
 - by optimizing temp tracking using a bit array
 - by allowing constants to have copy
 - by differentiating 32 <-> 64 bits conversions from moves in the
   frontend by using specific instructions

The latter change introduces 2 new mandatory ext/extu_i32_i64 ops.
For the future we might want to allow each guest to only implement 2 of
the 3 size changing ops as I started to do in the following patchset:
http://lists.nongnu.org/archive/html/qemu-devel/2015-07/msg03369.html
That said we probably want to experiment with that first and see the
impact on the performances. If wrongly implemented, things might seem
to work but some bugs might appear in very rare cases, like the
truncation problem we recently got on aarch64 and x86-64 hosts.
Alternatively we might want to always implement the 3 ops on all
backends to avoid multiplying variants of the code and with that bugs.

This patchset has been fully tested on x86-64 host, but only lightly
tested on aarch64, ppc64 and s390x hosts.

Note that the two first patches have already been sent separately on the
mailing list and should make their way to the 2.4 release. I have
included them as they are fixing bugs triggered by patches from these
series.

Changes v1->v2
 - Added patches 1 & 2
 - patch 3: use bitmap_zero instead of memset
            for the call op, only reset temps that are in use
 - patch 4: do not use a bool to detect copies

Aurelien Jarno (12):
  tcg: correctly mark dead inputs for mov with a constant
  tcg: mark temps as mem_coherent = 0 for mov with a constant
  tcg/optimize: optimize temps tracking
  tcg/optimize: add temp_is_const and temp_is_copy functions
  tcg/optimize: track const/copy status separately
  tcg/optimize: allow constant to have copies
  tcg: rename trunc_shr_i32 into trunc_shr_i64_i32
  tcg: don't abuse TCG type in tcg_gen_trunc_shr_i64_i32
  tcg: implement real ext_i32_i64 and extu_i32_i64 ops
  tcg/optimize: add optimizations for ext_i32_i64 and extu_i32_i64 ops
  tcg/optimize: do not remember garbage high bits for 32-bit ops
  tcg: update README about size changing ops

 tcg/README               |  20 +++-
 tcg/aarch64/tcg-target.c |   4 +
 tcg/aarch64/tcg-target.h |   2 +-
 tcg/i386/tcg-target.c    |   5 +
 tcg/i386/tcg-target.h    |   2 +-
 tcg/ia64/tcg-target.c    |   4 +
 tcg/ia64/tcg-target.h    |   2 +-
 tcg/optimize.c           | 259 +++++++++++++++++++++--------------------------
 tcg/ppc/tcg-target.c     |   6 ++
 tcg/ppc/tcg-target.h     |   2 +-
 tcg/s390/tcg-target.c    |   5 +
 tcg/s390/tcg-target.h    |   2 +-
 tcg/sparc/tcg-target.c   |  12 ++-
 tcg/sparc/tcg-target.h   |   2 +-
 tcg/tcg-op.c             |  16 ++-
 tcg/tcg-opc.h            |   7 +-
 tcg/tcg.c                |   4 +
 tcg/tcg.h                |   2 +-
 tcg/tci/tcg-target.c     |   4 +
 tcg/tci/tcg-target.h     |   2 +-
 tci.c                    |   6 +-
 21 files changed, 198 insertions(+), 170 deletions(-)

-- 
2.1.4