Merge remote-tracking branch 'remotes/rth/tags/pull-tcg-20181216' into staging

Merge remote-tracking branch 'remotes/rth/tags/pull-tcg-20181216' into staging

- Remove retranslation remenents
- Return success from patch_reloc
- Preserve 32-bit values as zero-extended on x86_64
- Make bswap during memory ops as optional
- Cleanup xxhash
- Revert constant pooling for tcg/sparc/

# gpg: Signature made Mon 17 Dec 2018 03:25:21 GMT
# gpg:                using RSA key 64DF38E8AF7E215F
# gpg: Good signature from "Richard Henderson <richard.henderson@linaro.org>"
# Primary key fingerprint: 7A48 1E78 868B 4DB6 A85A  05C0 64DF 38E8 AF7E 215F

* remotes/rth/tags/pull-tcg-20181216: (33 commits)
  xxhash: match output against the original xxhash32
  include: move exec/tb-hash-xx.h to qemu/xxhash.h
  exec: introduce qemu_xxhash{2,4,5,6,7}
  qht-bench: document -p flag
  tcg: Drop nargs from tcg_op_insert_{before,after}
  tcg/mips: Improve the add2/sub2 command to use TCG_TARGET_REG_BITS
  tcg: Add TCG_TARGET_HAS_MEMORY_BSWAP
  tcg/optimize: Optimize bswap
  tcg: Clean up generic bswap64
  tcg: Clean up generic bswap32
  tcg/i386: Add setup_guest_base_seg for FreeBSD
  tcg/i386: Precompute all guest_base parameters
  tcg/i386: Assume 32-bit values are zero-extended
  tcg/i386: Implement INDEX_op_extr{lh}_i64_i32 for 32-bit guests
  tcg/i386: Propagate is64 to tcg_out_qemu_ld_slow_path
  tcg/i386: Propagate is64 to tcg_out_qemu_ld_direct
  tcg/s390x: Return false on failure from patch_reloc
  tcg/ppc: Return false on failure from patch_reloc
  tcg/arm: Return false on failure from patch_reloc
  tcg/aarch64: Return false on failure from patch_reloc
  ...

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