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https://github.com/rust-lang/rust
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35 lines
1 KiB
Rust
35 lines
1 KiB
Rust
//@ revisions: INT32 INT16
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//@ compile-flags: -O
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//@ [INT32] ignore-16bit
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//@ [INT16] only-16bit
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#![crate_type = "lib"]
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#![feature(core_intrinsics)]
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use std::intrinsics::compare_bytes;
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#[no_mangle]
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// CHECK-LABEL: @bytes_cmp(
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pub unsafe fn bytes_cmp(a: *const u8, b: *const u8, n: usize) -> i32 {
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// INT32: %[[TEMP:.+]] = tail call i32 @memcmp(ptr %a, ptr %b, {{i32|i64}} %n)
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// INT32-NOT: sext
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// INT32: ret i32 %[[TEMP]]
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// INT16: %[[TEMP1:.+]] = tail call i16 @memcmp(ptr %a, ptr %b, i16 %n)
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// INT16: %[[TEMP2:.+]] = sext i16 %[[TEMP1]] to i32
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// INT16: ret i32 %[[TEMP2]]
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compare_bytes(a, b, n)
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}
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// Ensure that, even though there's an `sext` emitted by the intrinsic,
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// that doesn't end up pessiming checks against zero.
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#[no_mangle]
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// CHECK-LABEL: @bytes_eq(
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pub unsafe fn bytes_eq(a: *const u8, b: *const u8, n: usize) -> bool {
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// CHECK: call {{.+}} @{{bcmp|memcmp}}(ptr %a, ptr %b, {{i16|i32|i64}} %n)
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// CHECK-NOT: sext
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// INT32: icmp eq i32
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// INT16: icmp eq i16
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compare_bytes(a, b, n) == 0_i32
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}
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