Merge remote-tracking branch 'remotes/rth/tcg-next' into staging

* remotes/rth/tcg-next:
  tcg/i386: Use SHLX/SHRX/SARX instructions
  tcg/i386: Use ANDN instruction
  tcg/i386: Add tcg_out_vex_modrm
  tcg/i386: Move TCG_CT_CONST_* to tcg-target.c
  disas/i386: Disassemble ANDN/SHLX/SHRX/SHAX
  tcg/optimize: Add more identity simplifications
  tcg/optimize: Optmize ANDC X,Y,Y to MOV X,0
  tcg/optimize: Simply some logical ops to NOT
  tcg/optimize: Handle known-zeros masks for ANDC
  tcg/optimize: add known-zero bits compute for load ops
  tcg/optimize: improve known-zero bits for 32-bit ops
  tcg/optimize: fix known-zero bits optimization
  tcg/optimize: fix known-zero bits for right shift ops
  tcg-arm: The shift count of op_rotl_i32 is in args[2] not args[1].
  TCG: Fix 32-bit host allocation typo

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