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Revert "store ScalarPair via memset when one side is undef and the other side can be memset" #137894

Merged
merged 2 commits into from
Mar 4, 2025
Merged

Revert "store ScalarPair via memset when one side is undef and the other side can be memset" #137894

merged 2 commits into from
Mar 4, 2025

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@compiler-errors compiler-errors commented Mar 2, 2025 •
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cc #137892
reverts #135335

r? oli-obk

@rustbot rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. labels Mar 2, 2025
@compiler-errors compiler-errors changed the title No scalar pair opt Revert "store ScalarPair via memset when one side is undef and the other side can be memset" Mar 2, 2025
@compiler-errors compiler-errors marked this pull request as ready for review March 2, 2025 18:54
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rustbot commented Mar 2, 2025

Some changes occurred to the CTFE / Miri interpreter

cc @rust-lang/miri, @RalfJung, @oli-obk, @lcnr

Some changes occurred in compiler/rustc_codegen_gcc

cc @antoyo, @GuillaumeGomez

compiler-errors
compiler-errors commented Mar 2, 2025
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compiler/rustc_codegen_ssa/src/mir/rvalue.rs
match cg_elem.val {
OperandValue::Immediate(v) => {
if try_init_all_same(bx, v) {
return;
}
}
OperandValue::Pair(a, b) => {
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For future reference, on line 104:

The try_init_all_same tries to access a value that should be size u128, but since scalar pairs can be twice the size of u128 it ends up indexing out of bounds.

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This code will need to both check that the initialized half of the scalarpair is the same value, then emit another memset for the uninitialized part, and be a bit more careful to use the correct size of the value being passed into the function.

compiler-errors
compiler-errors commented Mar 2, 2025
View reviewed changes
tests/codegen/slice-init.rs
// CHECK-NOT: select
// CHECK: br label %repeat_loop_header{{.*}}
// CHECK-NOT: switch
// CHECK: icmp
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I copied all this from above :clueless:

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oli-obk commented Mar 3, 2025

@bors r+ rollup

Has a really tiny effect on binary sizes, but that's not worth separating out of a rollup

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bors commented Mar 3, 2025

📌 Commit 5f575bc has been approved by oli-obk

It is now in the queue for this repository.

@bors bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Mar 3, 2025
@matthiaskrgr matthiaskrgr mentioned this pull request Mar 3, 2025
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bors added a commit to rust-lang-ci/rust that referenced this pull request Mar 4, 2025
@bors
Auto merge of rust-lang#137959 - matthiaskrgr:rollup-62vjvwr, r=matth…
fd17dea 
…iaskrgr

Rollup of 12 pull requests

Successful merges:

 - rust-lang#135767 (Future incompatibility warning `unsupported_fn_ptr_calling_conventions`: Also warn in dependencies)
 - rust-lang#137852 (Remove layouting dead code for non-array SIMD types.)
 - rust-lang#137863 (Fix pretty printing of unsafe binders)
 - rust-lang#137882 (do not build additional stage on compiler paths)
 - rust-lang#137894 (Revert "store ScalarPair via memset when one side is undef and the other side can be memset")
 - rust-lang#137902 (Make `ast::TokenKind` more like `lexer::TokenKind`)
 - rust-lang#137921 (Subtree update of `rust-analyzer`)
 - rust-lang#137922 (A few cleanups after the removal of `cfg(not(parallel))`)
 - rust-lang#137939 (fix order on shl impl)
 - rust-lang#137946 (Fix docker run-local docs)
 - rust-lang#137955 (Always allow rustdoc-json tests to contain long lines)
 - rust-lang#137958 (triagebot.toml: Don't label `test/rustdoc-json` as A-rustdoc-search)

r? `@ghost`
`@rustbot` modify labels: rollup
@bors bors merged commit 70b9968 into rust-lang:master Mar 4, 2025
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@rustbot rustbot added this to the 1.87.0 milestone Mar 4, 2025
rust-timer added a commit to rust-lang-ci/rust that referenced this pull request Mar 4, 2025
@rust-timer
Unrolled build for rust-lang#137894
b8307b3 
Rollup merge of rust-lang#137894 - compiler-errors:no-scalar-pair-opt, r=oli-obk

Revert "store ScalarPair via memset when one side is undef and the other side can be memset"

cc rust-lang#137892
reverts rust-lang#135335

r? oli-obk
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lqd commented Mar 6, 2025 •
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We need this on beta to fix #137892

@rustbot label +beta-nominated cc @apiraino for late meeting addition (no rush, and no worries if it slips: 1.86 is a month away)

@lqd lqd added the beta-nominated Nominated for backporting to the compiler in the beta channel. label Mar 6, 2025
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@wesleywiser wesleywiser mentioned this pull request Mar 6, 2025
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apiraino commented Mar 6, 2025

Beta backport accepted as per compiler team on Zulip. A backport PR will be authored by the release team at the end of the current development cycle. Backport labels handled by them.

@rustbot label +beta-accepted

@rustbot rustbot added the beta-accepted Accepted for backporting to the compiler in the beta channel. label Mar 6, 2025
@cuviper cuviper mentioned this pull request Mar 7, 2025
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@cuviper cuviper modified the milestones: 1.87.0, 1.86.0 Mar 7, 2025
@cuviper cuviper removed the beta-nominated Nominated for backporting to the compiler in the beta channel. label Mar 7, 2025
bors added a commit to rust-lang-ci/rust that referenced this pull request Mar 8, 2025
@bors
Auto merge of rust-lang#138190 - cuviper:beta-next, r=cuviper
7e3c838 
[beta] backports

- Don't infer attributes of virtual calls based on the function body rust-lang#137669
- Revert "store ScalarPair via memset when one side is undef and the other side can be memset" rust-lang#137894

r? cuviper
bors added a commit to rust-lang-ci/rust that referenced this pull request Mar 8, 2025
@bors
Auto merge of rust-lang#138190 - cuviper:beta-next, r=cuviper
b2af9a5 
[beta] backports

- Don't infer attributes of virtual calls based on the function body rust-lang#137669
- Revert "store ScalarPair via memset when one side is undef and the other side can be memset" rust-lang#137894
- Do not install rustup on Rust for Linux job rust-lang#137947

r? cuviper
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