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https://github.com/rust-lang/rust
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3554036280
An `assume` would definitely not be worth it, but since the flag is almost free we might as well tell LLVM this, especially on `_unchecked` calls where there's no obvious way for it to deduce it. (Today neither safe nor unsafe indexing gets it: <https://rust.godbolt.org/z/G1jYT548s>)
36 lines
884 B
Rust
36 lines
884 B
Rust
// compile-flags: -O
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// only-64bit (because the LLVM type of i64 for usize shows up)
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// ignore-debug: the debug assertions get in the way
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#![crate_type = "lib"]
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use std::ops::Range;
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// CHECK-LABEL: @index_by_range(
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#[no_mangle]
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pub fn index_by_range(x: &[u16], r: Range<usize>) -> &[u16] {
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// CHECK: sub nuw i64
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&x[r]
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}
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// CHECK-LABEL: @get_unchecked_by_range(
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#[no_mangle]
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pub unsafe fn get_unchecked_by_range(x: &[u16], r: Range<usize>) -> &[u16] {
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// CHECK: sub nuw i64
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x.get_unchecked(r)
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}
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// CHECK-LABEL: @index_mut_by_range(
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#[no_mangle]
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pub fn index_mut_by_range(x: &mut [i32], r: Range<usize>) -> &mut [i32] {
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// CHECK: sub nuw i64
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&mut x[r]
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}
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// CHECK-LABEL: @get_unchecked_mut_by_range(
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#[no_mangle]
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pub unsafe fn get_unchecked_mut_by_range(x: &mut [i32], r: Range<usize>) -> &mut [i32] {
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// CHECK: sub nuw i64
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x.get_unchecked_mut(r)
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}
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