Barely. x86 is fading. Arm doesn't do this in GCC or Clang.

> Shorter usually means faster

It depends, so spouting generalities doesn't mean anything. Instruction cache line filling vs. cycle reduction vs. reservation station ordering is typically a compiler constraints optimization problem(s).

Arm doesn't do this in GCC or Clang.

Because Arm64 has a zero register, and Arm32 has small immediates, and all instructions are uniformly long.