Type annotations for instruction operands are omitted, e.g.
```
%3 = struct $S(%1, %2)
```
Operand types are redundant anyway and were only used for sanity checking in the SIL parser.
But: operand types _are_ printed if the definition of the operand value was not printed yet.
This happens:
* if the block with the definition appears after the block where the operand's instruction is located
* if a block or instruction is printed in isolation, e.g. in a debugger
The old behavior can be restored with `-Xllvm -sil-print-types`.
This option is added to many existing test files which check for operand types in their check-lines.
If the branch-block injects a certain enum case and the destination switches on that enum, it's worth jump threading. E.g.
inject_enum_addr %enum : $*Optional<T>, #Optional.some
... // no memory writes here
br DestBB
DestBB:
... // no memory writes here
switch_enum_addr %enum : $*Optional<T>, case #Optional.some ...
This enables removing all code with optionals in a loop, which iterates over an array of address-only elements, e.g.
func test<T>(_ items: [T]) {
for i in items {
print(i)
}
}
