bpf: ISA V4 sign-extending move and load insns [PR110782,PR110784]
BPF ISA V4 introduces sign-extending move and load operations. This
patch makes the BPF backend generate those instructions, when enabled
and useful.
A new option, -m[no-]smov gates generation of these instructions, and is
enabled by default for -mcpu=v4 and above. Tests for the new
instructions and documentation for the new options are included.
* gcc.target/bpf/sload-1.c: New test.
* gcc.target/bpf/sload-pseudoc-1.c: New test.
* gcc.target/bpf/smov-1.c: New test.
* gcc.target/bpf/smov-pseudoc-1.c: New test.