Auto merge of #137707 - RalfJung:aliasing-model-perf, r= · rust-lang/rust@8d95477 (original) (raw)
`@@ -392,13 +392,13 @@ fn adjust_for_rust_scalar<'tcx>(
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`// potentially self-referential types (see
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`// https://github.com/rust-lang/unsafe-code-guidelines/issues/381). If LLVM had a way
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`// to say "dereferenceable on entry" we could use it here.
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``
`-
attrs.pointee_size = match kind {
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``
`-
PointerKind::Box { .. }
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``
`-
| PointerKind::SharedRef { frozen: false }
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``
`-
| PointerKind::MutableRef { unpin: false } => Size::ZERO,
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``
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PointerKind::SharedRef { frozen: true }
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``
`-
| PointerKind::MutableRef { unpin: true } => pointee.size,
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``
`-
};
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`+
// attrs.pointee_size = match kind {
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`+
// PointerKind::Box { .. }
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`+
// | PointerKind::SharedRef { frozen: false }
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`+
// | PointerKind::MutableRef { unpin: false } => Size::ZERO,
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`+
// PointerKind::SharedRef { frozen: true }
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// | PointerKind::MutableRef { unpin: true } => pointee.size,
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// };
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``
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`` // The aliasing rules for Box<T> are still not decided, but currently we emit
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`` // noalias for it. This can be turned off using an unstable flag.
``
`@@ -424,11 +424,11 @@ fn adjust_for_rust_scalar<'tcx>(
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`` // We can never add noalias in return position; that LLVM attribute has some very surprising semantics
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`// (see https://github.com/rust-lang/unsafe-code-guidelines/issues/385#issuecomment-1368055745).
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`if no_alias && !is_return {
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``
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attrs.set(ArgAttribute::NoAlias);
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//attrs.set(ArgAttribute::NoAlias);
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`}
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``
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`if matches!(kind, PointerKind::SharedRef { frozen: true }) && !is_return {
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``
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attrs.set(ArgAttribute::ReadOnly);
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`+
//attrs.set(ArgAttribute::ReadOnly);
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`}
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`}
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`}
`