[PATCH 00/28] tcg: bswap improvements

[Richard Henderson]

This has been on my to-do list for several years, and I've
finally spent a rainy weekend doing something about it.

The current tcg bswap opcode is fairly strict: for swaps smaller
than the TCGv size, it requires zero-extended input and provides
zero-extended output.

This has meant that various tcg/ backends have their own handling
of bswap when it comes to memory, to minimize overhead for stores
(which do not care about zero-extended output) or for signed loads
(which would rather not sign-extend after zero-extending).

Solve this by adding some operation flags to the tcg bswap opcode:

  TCG_BSWAP_IZ  -- Input is Zero extended
  TCG_BSWAP_OZ  -- Output is Zero extended
  TCG_BSWAP_OS  -- Output is Sign extended

For instance, bswap before store would not set any of these flags,
allowing unextended input and producing unextended output.

The patch set can be broken into sections:

  * patches 1 - 16 implement the functionality in the backend,
    but do not provide the interface to use it,

  * patch 17 enables the interface,

  * patches 18 - 25 use the new interface in the front ends

  * patches 26 - 28 remove some tcg backend complexity,
    leaving the bswap handling to the middle-end.


r~


Richard Henderson (28):
  tcg: Add flags argument to bswap opcodes
  tcg/i386: Support bswap flags
  tcg/aarch64: Support bswap flags
  tcg/arm: Support bswap flags
  tcg/ppc: Split out tcg_out_ext{8,16,32}s
  tcg/ppc: Split out tcg_out_sari{32,64}
  tcg/ppc: Split out tcg_out_bswap16
  tcg/ppc: Split out tcg_out_bswap32
  tcg/ppc: Split out tcg_out_bswap64
  tcg/ppc: Support bswap flags
  tcg/ppc: Use power10 byte-reverse instructions
  tcg/s390: Support bswap flags
  tcg/mips: Support bswap flags in tcg_out_bswap16
  tcg/mips: Support bswap flags in tcg_out_bswap32
  tcg/tci: Support bswap flags
  tcg: Handle new bswap flags during optimize
  tcg: Add flags argument to tcg_gen_bswap16_*, tcg_gen_bswap32_i64
  tcg: Make use of bswap flags in tcg_gen_qemu_ld_*
  tcg: Make use of bswap flags in tcg_gen_qemu_st_*
  target/arm: Improve REV32
  target/arm: Improve vector REV
  target/arm: Improve REVSH
  target/i386: Improve bswap translation
  target/sh4: Improve swap.b translation
  target/mips: Fix gen_mxu_s32ldd_s32lddr
  tcg/arm: Unset TCG_TARGET_HAS_MEMORY_BSWAP
  tcg/aarch64: Unset TCG_TARGET_HAS_MEMORY_BSWAP
  tcg/riscv: Remove MO_BSWAP handling

 include/tcg/tcg-op.h            |   8 +-
 include/tcg/tcg-opc.h           |  10 +-
 include/tcg/tcg.h               |  12 ++
 tcg/aarch64/tcg-target.h        |   2 +-
 tcg/arm/tcg-target.h            |   2 +-
 target/arm/translate-a64.c      |  21 +--
 target/arm/translate.c          |   4 +-
 target/i386/tcg/translate.c     |  14 +-
 target/mips/tcg/mxu_translate.c |   6 +-
 target/s390x/translate.c        |   4 +-
 target/sh4/translate.c          |   3 +-
 tcg/optimize.c                  |  56 ++++++-
 tcg/tcg-op.c                    | 143 +++++++++++------
 tcg/tci.c                       |   3 +-
 tcg/aarch64/tcg-target.c.inc    |  99 +++++-------
 tcg/arm/tcg-target.c.inc        | 272 ++++++++++++--------------------
 tcg/i386/tcg-target.c.inc       |  20 ++-
 tcg/mips/tcg-target.c.inc       |  99 ++++++------
 tcg/ppc/tcg-target.c.inc        | 199 ++++++++++++++---------
 tcg/riscv/tcg-target.c.inc      |  64 ++++----
 tcg/s390/tcg-target.c.inc       |  34 +++-
 tcg/tci/tcg-target.c.inc        |  23 ++-
 tcg/README                      |  18 ++-
 23 files changed, 607 insertions(+), 509 deletions(-)

-- 
2.25.1