Merge remote-tracking branch 'remotes/rth/tags/pull-tcg-20170110' into staging

TCG opcodes for extract, clz, ctz, ctpop

# gpg: Signature made Wed 11 Jan 2017 02:12:41 GMT
# gpg:                using RSA key 0xAD1270CC4DD0279B
# gpg: Good signature from "Richard Henderson <rth7680@gmail.com>"
# gpg:                 aka "Richard Henderson <rth@redhat.com>"
# gpg:                 aka "Richard Henderson <rth@twiddle.net>"
# Primary key fingerprint: 9CB1 8DDA F8E8 49AD 2AFC  16A4 AD12 70CC 4DD0 279B

* remotes/rth/tags/pull-tcg-20170110: (65 commits)
  tcg/i386: Handle ctpop opcode
  tcg/ppc: Handle ctpop opcode
  tcg: Use ctpop to generate ctz if needed
  tests: New test-bitcnt
  qemu/host-utils.h: Reduce the operation count in the fallback ctpop
  target-i386: Use ctpop helper
  target-tilegx: Use ctpop helper
  target-sparc: Use ctpop helper
  target-s390x: Avoid a loop for popcnt
  target-ppc: Use ctpop helper
  target-alpha: Use ctpop helper
  tcg: Add opcode for ctpop
  target-xtensa: Use clrsb helper
  target-tricore: Use clrsb helper
  target-arm: Use clrsb helper
  tcg: Add helpers for clrsb
  tcg/i386: Rely on undefined/undocumented behaviour of BSF/BSR
  tcg/i386: Handle ctz and clz opcodes
  tcg/i386: Allow bmi2 shiftx to have non-matching operands
  tcg/i386: Hoist common arguments in tcg_out_op
  ...

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>