Merge trivial x86 code generation annoyances
- Introduce helper macros for clang asm input problems
- use said macros to improve trivially stupid code generation issues in
bitops and array_index_mask_nospec
- also improve codegen with 32-bit array index comparisons
None of these really matter, but I look at code generation and profiles
fairly regularly, and these misfeatures caused the generated code to
look really odd and distract from the real issues.
* branch 'x86-codegen' of local tree:
x86: improve bitop code generation with clang
x86: improve array_index_mask_nospec() code generation
clang: work around asm input constraint problems
