AstGen: elide block instruction when already in empty body

In the code `if (cond) { ... }`, the "then body" of the `if` is
technically a block. However, we don't need to emit a real ZIR `block`
corresponding to it, because we are already within a condbr body; we
have a separate gz, and appropriate scoping for allocs and debug
variables. In this case, and many like it, we can trivially elide the
block here, instead emitting the block statements directly into the
current `GenZir`. This results in a significant decrease in ZIR bytes
for real code.

0 files changed, 0 insertions, 0 deletions