Merge remote-tracking branch 'remotes/rth/tags/pull-tcg-20190426' into staging

Add tcg_gen_extract2_*.
Deal with overflow of TranslationBlocks.
Respect access_type in io_readx.

# gpg: Signature made Fri 26 Apr 2019 18:17:01 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-20190426:
  cputlb: Fix io_readx() to respect the access_type
  tcg/arm: Restrict constant pool displacement to 12 bits
  tcg/ppc: Allow the constant pool to overflow at 32k
  tcg: Restart TB generation after out-of-line ldst overflow
  tcg: Restart TB generation after constant pool overflow
  tcg: Restart TB generation after relocation overflow
  tcg: Restart after TB code generation overflow
  tcg: Hoist max_insns computation to tb_gen_code
  tcg/aarch64: Support INDEX_op_extract2_{i32,i64}
  tcg/arm: Support INDEX_op_extract2_i32
  tcg/i386: Support INDEX_op_extract2_{i32,i64}
  tcg: Use extract2 in tcg_gen_deposit_{i32,i64}
  tcg: Use deposit and extract2 in tcg_gen_shifti_i64
  tcg: Add INDEX_op_extract2_{i32,i64}
  tcg: Implement tcg_gen_extract2_{i32,i64}

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