Force LLVM to use CMOV for binary search · patricklam/verify-rust-std@5119266 (original) (raw)
`@@ -1010,6 +1010,34 @@ pub const fn unlikely(b: bool) -> bool {
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`}
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/// Returns either true_val or false_val depending on condition b with a
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/// hint to the compiler that this condition is unlikely to be correctly
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/// predicted by a CPU's branch predictor (e.g. a binary search).
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///
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/// This is otherwise functionally equivalent to if b { true_val } else { false_val }.
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///
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/// Note that, unlike most intrinsics, this is safe to call;
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/// it does not require an unsafe block.
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/// Therefore, implementations must not require the user to uphold
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/// any safety invariants.
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///
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/// This intrinsic does not have a stable counterpart.
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#[cfg(not(bootstrap))]
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#[unstable(feature = "core_intrinsics", issue = "none")]
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#[rustc_intrinsic]
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#[rustc_nounwind]
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#[miri::intrinsic_fallback_is_spec]
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#[inline]
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pub fn select_unpredictable(b: bool, true_val: T, false_val: T) -> T {
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if b { true_val } else { false_val }
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}
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#[cfg(bootstrap)]
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#[inline]
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pub fn select_unpredictable(b: bool, true_val: T, false_val: T) -> T {
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if b { true_val } else { false_val }
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}
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`extern "rust-intrinsic" {
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`/// Executes a breakpoint trap, for inspection by a debugger.
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`///
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