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Revert "Disable the machine outliner by default" #88388

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Merged
merged 1 commit into from
Aug 28, 2021
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Revert "Disable the machine outliner by default" #88388

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13 changes: 7 additions & 6 deletions compiler/rustc_codegen_llvm/src/llvm_util.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -89,13 +89,14 @@ unsafe fn configure_llvm(sess: &Session) {
add("-generate-arange-section", false);
}

// FIXME(nagisa): disable the machine outliner by default in LLVM versions 11, where it was
// introduced and up.
// Disable the machine outliner by default in LLVM versions 11 and LLVM
// version 12, where it leads to miscompilation.
//
// This should remain in place until https://reviews.llvm.org/D103167 is fixed. If LLVM
// has been upgraded since, consider adjusting the version check below to contain an upper
// bound.
if llvm_util::get_version() >= (11, 0, 0) {
// Ref:
// - https://github.com/rust-lang/rust/issues/85351
// - https://reviews.llvm.org/D103167
let llvm_version = llvm_util::get_version();
if llvm_version >= (11, 0, 0) && llvm_version < (13, 0, 0) {
add("-enable-machine-outliner=never", false);
}
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@bjorn3 bjorn3 Aug 27, 2021

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What is the policy on this? Should the disable only be reverted for the rust fork of LLVM or LLVM 13 and up?

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@luqmana luqmana Aug 27, 2021

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I'd say disable for >= 11.0.0 && < 12.0.1

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@ldm0 ldm0 Aug 28, 2021

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Our fork of 12.0.1 doesn't contain the fix commit. https://github.com/rust-lang/llvm-project/tree/rustc/12.0-2021-07-10 So I changed the disabling range to >= 11.0.0 && < 13.0.0


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