mirror of https://github.com/rust-lang/rust.git
39 lines
1.1 KiB
Rust
39 lines
1.1 KiB
Rust
//@ revisions: OPT2 OPT3
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//@[OPT2] compile-flags: -Copt-level=2
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//@[OPT3] compile-flags: -C opt-level=3
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// some targets don't do the opt we are looking for
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//@[OPT3] only-64bit
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//@ min-llvm-version: 18.1.3
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#![crate_type = "lib"]
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#![no_std]
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// The code is from https://github.com/rust-lang/rust/issues/122805.
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// Ensure we do not generate the shufflevector instruction
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// to avoid complicating the code.
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// CHECK-LABEL: define{{.*}}void @convert(
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// CHECK-NOT: shufflevector
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// On higher opt levels, this should just be a bswap:
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// OPT3: load <8 x i16>
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// OPT3-NEXT: call <8 x i16> @llvm.bswap
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// OPT3-NEXT: store <8 x i16>
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// OPT3-NEXT: ret void
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#[no_mangle]
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pub fn convert(value: [u16; 8]) -> [u8; 16] {
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#[cfg(target_endian = "little")]
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let bswap = u16::to_be;
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#[cfg(target_endian = "big")]
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let bswap = u16::to_le;
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let addr16 = [
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bswap(value[0]),
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bswap(value[1]),
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bswap(value[2]),
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bswap(value[3]),
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bswap(value[4]),
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bswap(value[5]),
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bswap(value[6]),
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bswap(value[7]),
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];
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unsafe { core::mem::transmute::<_, [u8; 16]>(addr16) }
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}
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