363c202581
Partially reverts 109612, as after 109993 these aren't actually equivalent any more, and I'm no longer confident this was ever an improvement in the first place.
44 lines
1.5 KiB
Rust
44 lines
1.5 KiB
Rust
// unit-test: InstSimplify
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// compile-flags: -C panic=abort
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#![crate_type = "lib"]
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#![feature(core_intrinsics)]
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#![feature(custom_mir)]
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use std::intrinsics::mir::*;
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use std::mem::{MaybeUninit, ManuallyDrop, transmute};
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// EMIT_MIR combine_transmutes.identity_transmutes.InstSimplify.diff
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pub unsafe fn identity_transmutes() {
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// These are nops and should be removed
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let _a = transmute::<i32, i32>(1);
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let _a = transmute::<Vec<i32>, Vec<i32>>(Vec::new());
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}
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#[custom_mir(dialect = "runtime", phase = "initial")]
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// EMIT_MIR combine_transmutes.integer_transmutes.InstSimplify.diff
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pub unsafe fn integer_transmutes() {
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mir! {
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{
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let A = CastTransmute::<i32, u32>(1); // Can be a cast
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let B = CastTransmute::<i32, i64>(1); // UB
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let C = CastTransmute::<u64, i64>(1); // Can be a cast
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let D = CastTransmute::<u64, u32>(1); // UB
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let E = CastTransmute::<isize, usize>(1); // Can be a cast
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Return()
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}
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}
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}
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// EMIT_MIR combine_transmutes.adt_transmutes.InstSimplify.diff
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pub unsafe fn adt_transmutes() {
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let _a: u8 = transmute(Some(std::num::NonZeroU8::MAX));
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let _a: i16 = transmute(std::num::Wrapping(0_i16));
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let _a: u16 = transmute(std::num::Wrapping(0_i16));
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let _a: u32 = transmute(Union32 { i32: 0 });
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let _a: i32 = transmute(Union32 { u32: 0 });
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let _a: ManuallyDrop<String> = transmute(MaybeUninit::<String>::uninit());
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}
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pub union Union32 { u32: u32, i32: i32 }
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