26 lines
591 B
Rust
26 lines
591 B
Rust
#![feature(compiler_builtins_lib)]
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extern crate compiler_builtins;
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use compiler_builtins::int::__clzsi2;
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#[test]
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fn __clzsi2_test() {
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let mut i: usize = core::usize::MAX;
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// Check all values above 0
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while i > 0 {
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assert_eq!(__clzsi2(i) as u32, i.leading_zeros());
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i >>= 1;
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}
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// check 0 also
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i = 0;
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assert_eq!(__clzsi2(i) as u32, i.leading_zeros());
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// double check for bit patterns that aren't just solid 1s
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i = 1;
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for _ in 0..63 {
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assert_eq!(__clzsi2(i) as u32, i.leading_zeros());
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i <<= 2;
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i += 1;
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}
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}
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