Allow enum and union literals to also create SSA values
#138759
Merged
+380
−77
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
|
r? @Nadrieril rustbot has assigned @Nadrieril. Use |
rustbot
added
S-waiting-on-review
|
Some changes occurred in compiler/rustc_codegen_ssa |
This comment has been minimized.
This comment has been minimized.
|
These commits modify the If this was unintentional then you should revert the changes before this PR is merged. |
|
r? codegen |
|
Spiderman meme |
|
@bors try @rust-timer queue |
This comment has been minimized.
This comment has been minimized.
rustbot
added
the
S-waiting-on-perf
bors
added a commit
to rust-lang-ci/rust
that referenced
this pull request
Mar 20, 2025
Allow `enum` and `union` literals to also create SSA values Today, `Some(x)` always goes through an `alloca`, even in trivial cases where the niching means the constructor doesn't even change the value. For example, <https://rust.godbolt.org/z/6KG6PqoYz> ```rust pub fn demo(r: &i32) -> Option<&i32> { Some(r) } ``` currently emits the IR ```llvm define align 4 ptr `@demo(ptr` align 4 %r) unnamed_addr { start: %_0 = alloca [8 x i8], align 8 store ptr %r, ptr %_0, align 8 %0 = load ptr, ptr %_0, align 8 ret ptr %0 } ``` but with this PR it becomes just ```llvm define align 4 ptr `@demo(ptr` align 4 %r) unnamed_addr { start: ret ptr %r } ``` (Of course the optimizer can clean that up, but it'd be nice if it didn't have to -- especially in debug where it doesn't run. This is like rust-lang#123886, but that only handled non-simd `struct`s -- this PR generalizes it to all non-simd ADTs.) There's two commits you can review independently: 1. The first is simplifying how the aggregate handling works. Past-me wrote something overly complicated, needing arrayvecs and zipping, depending on a careful iteration order of the fields, and fragile enough that even for just structs it needed extra double-checks to make sure it even made the right variant. It's replaced with something far more direct that works just like `extract_field`: use the offset to put it in exactly the correct immediate in the `OperandValue`. This doesn't support anything new, just refactors -- including moving some things off `FunctionCx` that had no reason to be there. (I have no idea why my past self put them there.) 2. The second extends that work to support more ADTs. That means handing variants other than `FIRST_VARIANT`, handling the active field for unions, refactoring the discriminant code so the Place and Operand parts can share the calculation, etc.
|
☀️ Try build successful - checks-actions |
This comment has been minimized.
This comment has been minimized.
|
Finished benchmarking commit (875f416): comparison URL. Overall result: ❌✅ regressions and improvements - please read the text belowBenchmarking this pull request likely means that it is perf-sensitive, so we're automatically marking it as not fit for rolling up. While you can manually mark this PR as fit for rollup, we strongly recommend not doing so since this PR may lead to changes in compiler perf. Next Steps: If you can justify the regressions found in this try perf run, please indicate this with @bors rollup=never Instruction countThis is the most reliable metric that we have; it was used to determine the overall result at the top of this comment. However, even this metric can sometimes exhibit noise.
Max RSS (memory usage)Results (primary -2.3%)This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.
CyclesResults (secondary -2.1%)This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.
Binary sizeResults (primary -0.1%, secondary -0.1%)This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.
Bootstrap: 775.297s -> 774.424s (-0.11%) |
rustbot
added
perf-regression
This comment has been minimized.
This comment has been minimized.
scottmcm
force-pushed
the
operand-builder
branch
from
9423566 to
a9031aa
Compare
|
Ben said I should re-roll this |
|
hello. |
|
@bors try |
bors
added a commit
that referenced
this pull request
Jul 4, 2025
Allow `enum` and `union` literals to also create SSA values Today, `Some(x)` always goes through an `alloca`, even in trivial cases where the niching means the constructor doesn't even change the value. For example, <https://rust.godbolt.org/z/6KG6PqoYz> ```rust pub fn demo(r: &i32) -> Option<&i32> { Some(r) } ``` currently emits the IR ```llvm define align 4 ptr `@demo(ptr` align 4 %r) unnamed_addr { start: %_0 = alloca [8 x i8], align 8 store ptr %r, ptr %_0, align 8 %0 = load ptr, ptr %_0, align 8 ret ptr %0 } ``` but with this PR it becomes just ```llvm define align 4 ptr `@demo(ptr` align 4 %r) unnamed_addr { start: ret ptr %r } ``` (Of course the optimizer can clean that up, but it'd be nice if it didn't have to -- especially in debug where it doesn't run. This is like #123886, but that only handled non-simd `struct`s -- this PR generalizes it to all non-simd ADTs.) Doing this means handing variants other than `FIRST_VARIANT`, handling the active field for unions, refactoring the discriminant code so the Place and Operand parts can share the calculation, etc. Other PRs that led up to this one: - #142005 - #142103 - #142324 - #142383 --- try-job: aarch64-gnu
This comment has been minimized.
This comment has been minimized.
This comment has been minimized.
This comment has been minimized.
|
💔 Test failed - checks-actions |
|
The failure in bors was but those strings are clearly there in the failures in #138759 (comment) when I made it Let's try running it again with the test left alone and see what happens... |
bors
added a commit
that referenced
this pull request
Jul 4, 2025
Allow `enum` and `union` literals to also create SSA values Today, `Some(x)` always goes through an `alloca`, even in trivial cases where the niching means the constructor doesn't even change the value. For example, <https://rust.godbolt.org/z/6KG6PqoYz> ```rust pub fn demo(r: &i32) -> Option<&i32> { Some(r) } ``` currently emits the IR ```llvm define align 4 ptr `@demo(ptr` align 4 %r) unnamed_addr { start: %_0 = alloca [8 x i8], align 8 store ptr %r, ptr %_0, align 8 %0 = load ptr, ptr %_0, align 8 ret ptr %0 } ``` but with this PR it becomes just ```llvm define align 4 ptr `@demo(ptr` align 4 %r) unnamed_addr { start: ret ptr %r } ``` (Of course the optimizer can clean that up, but it'd be nice if it didn't have to -- especially in debug where it doesn't run. This is like #123886, but that only handled non-simd `struct`s -- this PR generalizes it to all non-simd ADTs.) Doing this means handing variants other than `FIRST_VARIANT`, handling the active field for unions, refactoring the discriminant code so the Place and Operand parts can share the calculation, etc. Other PRs that led up to this one: - #142005 - #142103 - #142324 - #142383 --- try-job: aarch64-gnu
This comment has been minimized.
This comment has been minimized.
|
💔 Test failed - checks-actions |
|
@bors try |
bors
added a commit
that referenced
this pull request
Jul 4, 2025
Allow `enum` and `union` literals to also create SSA values Today, `Some(x)` always goes through an `alloca`, even in trivial cases where the niching means the constructor doesn't even change the value. For example, <https://rust.godbolt.org/z/6KG6PqoYz> ```rust pub fn demo(r: &i32) -> Option<&i32> { Some(r) } ``` currently emits the IR ```llvm define align 4 ptr `@demo(ptr` align 4 %r) unnamed_addr { start: %_0 = alloca [8 x i8], align 8 store ptr %r, ptr %_0, align 8 %0 = load ptr, ptr %_0, align 8 ret ptr %0 } ``` but with this PR it becomes just ```llvm define align 4 ptr `@demo(ptr` align 4 %r) unnamed_addr { start: ret ptr %r } ``` (Of course the optimizer can clean that up, but it'd be nice if it didn't have to -- especially in debug where it doesn't run. This is like #123886, but that only handled non-simd `struct`s -- this PR generalizes it to all non-simd ADTs.) Doing this means handing variants other than `FIRST_VARIANT`, handling the active field for unions, refactoring the discriminant code so the Place and Operand parts can share the calculation, etc. Other PRs that led up to this one: - #142005 - #142103 - #142324 - #142383 --- try-job: aarch64-gnu
|
Sorry, I just got distracted by more recent PRs due to the rapidity of the |
|
☀️ Try build successful - checks-actions |
|
@bors r=saethlin |
bors
added
S-waiting-on-bors
|
☀️ Test successful - checks-actions |
What is this?This is an experimental post-merge analysis report that shows differences in test outcomes between the merged PR and its parent PR.Comparing d98a5da (parent) -> 733b47e (this PR) Test differencesShow 10 test diffsStage 1
Stage 2
Additionally, 4 doctest diffs were found. These are ignored, as they are noisy. Job group index
Test dashboardRun cargo run --manifest-path src/ci/citool/Cargo.toml -- \
test-dashboard 733b47ea4b1b86216f14ef56e49440c33933f230 --output-dir test-dashboardAnd then open Job duration changes
How to interpret the job duration changes?Job durations can vary a lot, based on the actual runner instance |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Today,
Some(x)always goes through analloca, even in trivial cases where the niching means the constructor doesn't even change the value.For example, https://rust.godbolt.org/z/6KG6PqoYz
currently emits the IR
but with this PR it becomes just
(Of course the optimizer can clean that up, but it'd be nice if it didn't have to -- especially in debug where it doesn't run. This is like #123886, but that only handled non-simd
structs -- this PR generalizes it to all non-simd ADTs.)Doing this means handing variants other than
FIRST_VARIANT, handling the active field for unions, refactoring the discriminant code so the Place and Operand parts can share the calculation, etc.Other PRs that led up to this one:
tag_fieldtoFieldIdxinVariants::Multiple#142005InterpCx::project_fieldto takeFieldIdx#142103FunctionCxfrom some codegen methods #142324try-job: aarch64-gnu