This commit expands on the foundations laid by https://github.com/ziglang/zig/pull/23177
and moves even more `Sema`-only functionality from `Value`
to `Sema.arith`. Specifically all shift and bitwise operations,
`@truncate`, `@bitReverse` and `@byteSwap` have been moved and
adapted to the new rules around `undefined`.
Especially the comptime shift operations have been basically
rewritten, fixing many open issues in the process.
New rules applied to operators:
* `<<`, `@shlExact`, `@shlWithOverflow`, `>>`, `@shrExact`: compile error if any operand is undef
* `<<|`, `~`, `^`, `@truncate`, `@bitReverse`, `@byteSwap`: return undef if any operand is undef
* `&`, `|`: Return undef if both operands are undef, turn undef into actual `0xAA` bytes otherwise
Additionally this commit canonicalizes the representation of
aggregates with all-undefined members in the `InternPool` by
disallowing them and enforcing the usage of a single typed
`undef` value instead. This reduces the amount of edge cases
and fixes a bunch of bugs related to partially undefined vecs.
List of operations directly affected by this patch:
* `<<`, `<<|`, `@shlExact`, `@shlWithOverflow`
* `>>`, `@shrExact`
* `&`, `|`, `~`, `^` and their atomic rmw + reduce pendants
* `@truncate`, `@bitReverse`, `@byteSwap`
https://github.com/ziglang/zig/issues/23635
I also added tests for `@rem()` with `denominator < 0` cause there were none before
I hope I added them in the correct place, if not I can change it ofc
Also remove `@frameSize`, closing #3654.
While the other machinery might remain depending on #23446, it is
settled that there will not be `async`/ `await` keywords in the
language.
* Sema: allow binary operations and boolean not on vectors of bool
* langref: Clarify use of operators on vectors (`and` and `or` not allowed)
closes#24093
* trailing whitespace
* langref: undefined _is_ materialized in all safe modes
I am also not super happy about the clause that immediately follows. I
_believe_ what we want to say here is that, simultaneously:
* undefined is guaranteed to be matrerialized in in all safe modes.
A Zig implementation that elides `ptr.* = undefined` in ReleaseSafe
mode would be a non-conforming implementation.
* A Zig program that relies on undefined being materialized is buggy.
But I don't think it's the time to engage this level of language-lawering!
This reverts commit dea72d15da, reversing
changes made to ab381933c8.
The changeset does not work as advertised and does not have sufficient
test coverage.
Reopens#22822
The previous language using subsets was really just stating a couple
of the properties of the union of a group of sets, and with a minor
error at that.
