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40 lines
1.3 KiB
Rust
40 lines
1.3 KiB
Rust
//@ compile-flags: -Copt-level=3
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#![crate_type = "lib"]
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// This test checks that we can inline drop_in_place in
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// unwind landing pads.
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// Without inlining, the box pointers escape via the call to drop_in_place,
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// and LLVM will not optimize out the pointer comparison.
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// With inlining, everything should be optimized out.
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// See https://github.com/rust-lang/rust/issues/46515
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// CHECK-LABEL: @check_no_escape_in_landingpad
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// CHECK: start:
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// CHECK-NEXT: ; call __rustc::__rust_no_alloc_shim_is_unstable_v2
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// CHECK-NEXT: tail call void @[[NO_ALLOC_SHIM:_R.+__rust_no_alloc_shim_is_unstable_v2]]()
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// CHECK-NEXT: ; call __rustc::__rust_no_alloc_shim_is_unstable_v2
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// CHECK-NEXT: tail call void @[[NO_ALLOC_SHIM]]()
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// CHECK-NEXT: ret void
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#[no_mangle]
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pub fn check_no_escape_in_landingpad(f: fn()) {
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let x = &*Box::new(0);
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let y = &*Box::new(0);
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if x as *const _ == y as *const _ {
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f();
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}
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}
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// Without inlining, the compiler can't tell that
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// dropping an empty string (in a landing pad) does nothing.
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// With inlining, the landing pad should be optimized out.
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// See https://github.com/rust-lang/rust/issues/87055
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// CHECK-LABEL: @check_eliminate_noop_drop
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// CHECK: call void %g()
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// CHECK-NEXT: ret void
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#[no_mangle]
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pub fn check_eliminate_noop_drop(g: fn()) {
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let _var = String::new();
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g();
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}
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