4630d1b23b
Apparently MIR borrowck cares about at least one of these for checking variance. In runtime MIR, though, there's no need for them as `PtrToPtr` does the same thing. (Banning them simplifies passes like GVN that no longer need to handle multiple cast possibilities.)
35 lines
1.0 KiB
Rust
35 lines
1.0 KiB
Rust
//@ test-mir-pass: InstSimplify
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//@ compile-flags: -Zinline-mir
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#![crate_type = "lib"]
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#![feature(core_intrinsics)]
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#[inline(always)]
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fn generic_cast<T, U>(x: *const T) -> *const U {
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x as *const U
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}
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// EMIT_MIR casts.redundant.InstSimplify.diff
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pub fn redundant<'a, 'b: 'a>(x: *const &'a u8) -> *const &'a u8 {
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// CHECK-LABEL: fn redundant(
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// CHECK: inlined generic_cast
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// CHECK-NOT: as
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generic_cast::<&'a u8, &'b u8>(x) as *const &'a u8
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}
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// EMIT_MIR casts.roundtrip.InstSimplify.diff
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pub fn roundtrip(x: *const u8) -> *const u8 {
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// CHECK-LABEL: fn roundtrip(
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// CHECK: _4 = _1;
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// CHECK: _3 = move _4 as *mut u8 (PtrToPtr);
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// CHECK: _2 = move _3 as *const u8 (PtrToPtr);
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x as *mut u8 as *const u8
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}
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// EMIT_MIR casts.roundtrip.InstSimplify.diff
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pub fn cast_thin_via_aggregate(x: *const u8) -> *const () {
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// CHECK-LABEL: fn cast_thin_via_aggregate(
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// CHECK: _2 = _1;
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// CHECK: _0 = move _2 as *const () (PtrToPtr);
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std::intrinsics::aggregate_raw_ptr(x, ())
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}
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