When merging two sorted blocks `left` and `right` if the last element in
`left` is <= the first in `right`, the blocks are already sorted.
Add this as an additional fast path by simply copying the whole left
block into the output and advancing the left pointer. The right block is
then treated the same way by the already present logic in the merge
loop.
Reduces runtime of .sort() to less than 50% of the previous, if the data
was already perfectly sorted. Sorted data with a few swaps are also
sorted quicker than before. The overhead of one comparison per merge
seems to be negligible.
If you try to put something that's bigger than a char into a char
literal, you get an error:
fn main() {
let c = 'ஶ்ரீ';
}
error: unterminated character constant:
This is a very compiler-centric message. Yes, it's technically
'unterminated', but that's not what you, the user did wrong.
Instead, this commit changes it to
error: character literal that's larger than a char:
As this actually tells you what went wrong.
Fixes#28851
If you try to put something that's bigger than a char into a char
literal, you get an error:
fn main() {
let c = 'ஶ்ரீ';
}
error: unterminated character constant:
This is a very compiler-centric message. Yes, it's technically
'unterminated', but that's not what you, the user did wrong.
Instead, this commit changes it to
error: character literal may only contain one codepoint
As this actually tells you what went wrong.
Fixes#28851
The "m" memory constraint in inline assembly is broken (generates incorrect code or triggers LLVM asserts) and should not be used. Instead, indirect memory operands should be used with "\*m", "=\*m" and "+\*m".
Clang does this transparently by transforming "m" constraints into "\*m" indirect constraints, but for now just being able to use "\*m" directly is enough since asm! isn't stable.
While "\*m" works fine as an input operand, "=\*m" and "+\*m" need to be specified as input operands because they take a pointer value as an input. This PR relaxes the constraint checker to allow constraints starting with "=" or "+" if the constraint string contains a "\*", which indicates an indirect operand.
This (indirectly) fixes these issues: #29382, #16383 and #13366. The code will need to be changed to use "\*m" instead of "m".
This branch implements a variant of trans that is based on MIR. It is very incomplete (intentionally), and had only the goal of laying out enough work to enable more incremental follow-on patches. Currently, only fns tagged with `#[rustc_mir]` use the new trans code. I plan to build up a meta-issue as well that tracks the various "not-yet-implemented" points. The only fn that has been tested so far is this amazingly complex "spike" fn:
```rust
#[rustc_mir]
fn sum(x: i32, y: i32) -> i32 {
x + y
}
```
In general, the most interesting commit is the last one. There are some points on which I would like feedback from @rust-lang/compiler:
- I did not use `Datum`. Originally, I thought that maybe just a `ValueRef` would be enough but I wound up with two very simple structures, `LvalueRef` and `OperandRef`, that just package up a `ValueRef` and a type. Because of MIR's structure, you don't wind up mixing by-ref and by-value so much, and I tend to think that a thinner abstraction layer is better here, but I'm not sure.
- Related to the above, I expect that sooner or later we will analyze temps (and maybe variables too) to find those whose address is never taken and which are word-sized and which perhaps meet a few other criteria. For those, we'll probably want to avoid the alloca, just because it means prettier code.
- I generally tried to re-use data structures from elsewhere in trans, though I'm sure we can trim these down.
- I didn't do any debuginfo primarily because it seems to want node-ids and we have only spans. I haven't really read into that code so I don't know what's going on there.
r? @nrc
`resolve_identifier` used to mark a variable as an upvar when used within a closure. However, the function is also used for the "unnecessary qualification" lint, which would mark paths whose last component had the same name as a local as upvars.
Fixes#29522
r? @eddyb
I think this should fix the test failures in debug mode from #29492
The assertion was written incorrectly, and I don't like the way the new assertion is written, but I _think_ it does the right thing now.
A line may be indented with either spaces or tabs, but not a mix of both. If there is a mix of tabs and spaces, only the kind that occurs first is counted.
This addresses issue #29268.
