Fix unused assignments in diverging branches
Fixesrust-lang/rust#156416
Add `location` and use `is_predecessor_of` to check in the control flow graph.
r? @ghost
I'd like to see whether there is performence regression.
This function doesn't have an obvious home, but there's little reason for it to
be in mir-transform, and having it in `rustc_driver_impl::pretty` at least puts
it near other callers of `write_mir_pretty`.
Have arrays' `drop_glue` just unsize and call the slice version
It's silly to emit two loops (because of the drop ladder -- just one in panic=abort) for every array length that's dropped when we can just polymorphize to the slice version.
Built atop rust-lang/rust#154327 to avoid conflicts later, so draft for now.
r? @WaffleLapkin
Simplify `intrinsic::raw_eq` in MIR when possible
After https://github.com/rust-lang/rust/pull/150945 things can inline enough to have this end up specific enough that we can remove it, for example changing `raw_eq::<[u8; 4]>(a, b)` → `Transmute(a) == Transmute(b)`.
The LLVM backend can also do this (and in more cases too) but we might as well do it in MIR instead when we can so it applies to all backends and other MIR optimizations can apply afterwards.
change the type of the argument of `drop_in_place` lang item to `&mut _`
We used to special case `core::ptr::drop_in_place` when computing LLVM argument attributes with this hack:
https://github.com/rust-lang/rust/blob/db5e2dc248fe5bb26f70d7baec46a3bca9fa3e1d/compiler/rustc_ty_utils/src/abi.rs#L383-L392
This is because even though `drop_in_place` takes a `*mut T` it is semantically a `&mut T` (remember how `&mut Self` is passed to `Drop::drop`). This is apparently relevant for perf.
This PR replaces this hack with a simpler solution -- it makes `drop_in_place` a thin wrapper around newly added `core::ptr::drop_glue`, which is the actual lang item and takes a `&mut T`:
https://github.com/rust-lang/rust/blob/d2563d5003bbecff1efc40c1f5673ceec603825b/library/core/src/ptr/mod.rs#L810-L833
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The rest of the PR is blessing tests and cleaning up things which are not necessary after this change.
One thing that is a bit awkward is that now that `drop_glue` is the actual lang item, a lot of the comments referring to `drop_in_place` are outdated. Should I try fixing that?
I've also changed `async_drop_in_place` to take a `&mut T`, and it simplified the code handling it a bit. (since it's unstable we don't need to introduce a wrapper)
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cc @RalfJung
Closes https://github.com/rust-lang/rust/issues/154274
Remove unused spans from AttributeKind
Recently I noticed some spans in diagnostic attributes were never used. I went through and checked the other variants too.
compiler: Print valid `-Zmir-enable-passes` names if invalid name is used
If a user passes an invalid name to `-Zmir-enable-passes`, print the valid names as a note.
To avoid the annoyance of having to keep blessing test output, completely normalize away the list of names in the test.
The diagnostic is duplicated, but that is not introduced by this commit. In other words, we don't make matters worse. The existing "is unknown and will be ignored" diagnostic is already duplicated, as can be seen in the existing test stderr.
The output is on one long line, but that makes normalization in tests easier, and I don't think we have to overdo this. We can let terminals wrap the line.
<details>
<summary>Click to expand current output</summary>
`note: valid MIR pass names are: AbortUnwindingCalls, AddCallGuards, AddMovesForPackedDrops, AddRetag, CheckAlignment, CheckCallRecursion, CheckConstItemMutation, CheckDropRecursion, CheckEnums, CheckForceInline, CheckInlineAlwaysTargetFeature, CheckLiveDrops, CheckNull, CheckPackedRef, CleanupPostBorrowck, CopyProp, CtfeLimit, DataflowConstProp, DeadStoreElimination-final, DeadStoreElimination-initial, Derefer, DestinationPropagation, EarlyOtherwiseBranch, ElaborateBoxDerefs, ElaborateDrops, EnumSizeOpt, EraseDerefTemps, ForceInline, FunctionItemReferences, GVN, ImpossiblePredicates, Inline, InstSimplify-after-simplifycfg, InstSimplify-before-inline, InstrumentCoverage, JumpThreading, KnownPanicsLint, LowerIntrinsics, LowerSliceLenCalls, Marker, MatchBranchSimplification, MentionedItems, MultipleReturnTerminators, PostAnalysisNormalize, PreCodegen, PromoteTemps, ReferencePropagation, RemoveNoopLandingPads, RemovePlaceMention, RemoveStorageMarkers, RemoveUninitDrops, RemoveUnneededDrops, RemoveZsts, ReorderBasicBlocks, ReorderLocals, RequiredConstsVisitor, SanityCheck, ScalarReplacementOfAggregates, SimplifyCfg-after-unreachable-enum-branching, SimplifyCfg-final, SimplifyCfg-initial, SimplifyCfg-make_shim, SimplifyCfg-post-analysis, SimplifyCfg-pre-optimizations, SimplifyCfg-promote-consts, SimplifyCfg-remove-false-edges, SimplifyComparisonIntegral, SimplifyConstCondition-after-const-prop, SimplifyConstCondition-after-inst-simplify, SimplifyConstCondition-final, SimplifyLocals-after-value-numbering, SimplifyLocals-before-const-prop, SimplifyLocals-final, SingleUseConsts, SsaRangePropagation, StateTransform, StripDebugInfo, Subtyper, UnreachableEnumBranching, UnreachablePropagation, Validator`
</details>
Reuse CTFE MIR for constructors.
For constructors, we manually build the MIR shim we want. We can just have `optimized_mir` call `mir_for_ctfe` instead of rebuilding the shim.
Add a `Local::arg(i)` helper constructor
While reading through stuff I was noticing just how many `+1` fixes there were in various places (and comments explaining those fixups), so this adds a new inherent helper on `Local` for making an argument to help make this clearer.
r? mir
If a user passes an invalid name to `-Zmir-enable-passes`, print the
valid names as a note.
The diagnostic is duplicated, but that is not introduced by this commit.
In other words, we don't make matters worse. The existing "is unknown
and will be ignored" diagnostic is already duplicated.
To avoid the annoyance of having to keep blessing test output,
completely normalize away the list of names in the test.
Do not run jump-threading for GPUs
GPU targets have convergent operations that must not be duplicated or
moved in or out of control-flow.
An example convergent operation is a barrier/syncthreads.
The only MIR pass affected by this is jump-threading, it can duplicate
calls. Disable jump-hreading for GPU targets to prevent generating
incorrect code.
This affects the amdgpu and nvptx targets.
Fixesrust-lang/rust#137086, see this issue for details.
Tracking issue: rust-lang/rust#135024
cc @RDambrosio016 @kjetilkjeka for nvptx
cc @ZuseZ4
It used to ICE when hitting an `assert_ne!(location.block, successor.block` due
to hitting a self-dominating bb
Fixed by checking *strict* domination instead of normal one
While reading through stuff I was noticing just how many `+1` fixes there were in various places (and comments explaining that fixup), so this adds a new inherent helper on `Local` for making an argument to help make this clearer.
Handle index projections in call destinations in DSE
Since call destinations are evaluated after call arguments, we can't turn copy arguments into moves if the same local is later used as an index projection in the call destination.
DSE call arg optimization: rust-lang/rust#113758
r? @cjgillot
cc @RalfJung
Since call destinations are evaluated after call arguments, we can't
turn copy arguments into moves if the same local is later used as an
index projection in the call destination.
Fix performance regression introduced in #142531 by excluding `Storage{Live,Dead}` from CGU size estimation
Fix performance regression introduced in rust-lang/rust#142531 ([rust-timer comment](https://github.com/rust-lang/rust/pull/142531#issuecomment-4273712294)) by excluding `Storage{Live,Dead}` from CGU size estimation.
Also, avoid unneeded work for storage removal in non-opt builds in CopyProp and GVN
by allocating local sets for the storage accounting only when `tcx.sess.emit_lifetime_markers()`.
r? saethlin
Refactor FnDecl and FnSig non-type fields into a new wrapper type
#### Why this Refactor?
This PR is part of an initial cleanup for the [arg splat experiment](https://github.com/rust-lang/rust/issues/153629), but it's a useful refactor by itself.
It refactors the non-type fields of `FnDecl`, `FnSig`, and `FnHeader` into a new packed wrapper types, based on this comment in the `splat` experiment PR:
https://github.com/rust-lang/rust/pull/153697#discussion_r3004637413
It also refactors some common `FnSig` creation settings into their own methods. I did this instead of creating a struct with defaults.
#### Relationship to `splat` Experiment
I don't think we can use functional struct updates (`..default()`) to create `FnDecl` and `FnSig`, because we need the bit-packing for the `splat` experiment.
Bit-packing will avoid breaking "type is small" assertions for commonly used types when `splat` is added.
This PR packs these types:
- ExternAbi: enum + `unwind` variants (38) -> 6 bits
- ImplicitSelfKind: enum variants (5) -> 3 bits
- lifetime_elision_allowed, safety, c_variadic: bool -> 1 bit
#### Minor Changes
Fixes some typos, and applies rustfmt to clippy files that got skipped somehow.
cyrgani