Merge remote-tracking branch 'remotes/rth/tags/pull-tcg-20190513' into staging

Improve code generation for vector duplication.
Add vector expansions for shifts by non-constant scalar.
Add vector expansions for shifts by vector.
Add integer and vector expansions for absolute value.
Several patches in preparation for Altivec.
Bug fix for tcg/aarch64 vs min/max.

# gpg: Signature made Tue 14 May 2019 00:58:02 BST
# gpg:                using RSA key 7A481E78868B4DB6A85A05C064DF38E8AF7E215F
# gpg:                issuer "richard.henderson@linaro.org"
# gpg: Good signature from "Richard Henderson <richard.henderson@linaro.org>" [full]
# Primary key fingerprint: 7A48 1E78 868B 4DB6 A85A  05C0 64DF 38E8 AF7E 215F

* remotes/rth/tags/pull-tcg-20190513: (31 commits)
  tcg/aarch64: Do not advertise minmax for MO_64
  target/xtensa: Use tcg_gen_abs_i32
  target/tricore: Use tcg_gen_abs_tl
  target/s390x: Use tcg_gen_abs_i64
  target/ppc: Use tcg_gen_abs_tl
  target/ppc: Use tcg_gen_abs_i32
  target/cris: Use tcg_gen_abs_tl
  target/arm: Use tcg_gen_abs_i64 and tcg_gen_gvec_abs
  tcg/aarch64: Support vector absolute value
  tcg/i386: Support vector absolute value
  tcg: Add support for vector absolute value
  tcg: Add support for integer absolute value
  tcg/i386: Support vector scalar shift opcodes
  tcg: Add gvec expanders for vector shift by scalar
  tcg/aarch64: Support vector variable shift opcodes
  tcg/i386: Support vector variable shift opcodes
  tcg: Add gvec expanders for variable shift
  tcg: Add INDEX_op_dupm_vec
  tcg/aarch64: Implement tcg_out_dupm_vec
  tcg/i386: Implement tcg_out_dupm_vec
  ...

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