diff options
5 files changed, 54 insertions, 13 deletions
diff --git a/compiler/rustc_mir_transform/src/remove_zsts.rs b/compiler/rustc_mir_transform/src/remove_zsts.rs index e37ead3674b..55e5701bd0a 100644 --- a/compiler/rustc_mir_transform/src/remove_zsts.rs +++ b/compiler/rustc_mir_transform/src/remove_zsts.rs @@ -46,15 +46,17 @@ fn trivially_zst<'tcx>(ty: Ty<'tcx>, tcx: TyCtxt<'tcx>) -> Option<bool> { ty::FnDef(..) | ty::Never => Some(true), ty::Tuple(fields) if fields.is_empty() => Some(true), ty::Array(_ty, len) if let Some(0) = len.try_to_target_usize(tcx) => Some(true), - // maybe ZST (could be more precise) - ty::Adt(..) - | ty::Array(..) - | ty::Closure(..) - | ty::CoroutineClosure(..) - | ty::Tuple(..) - | ty::Alias(ty::Opaque, ..) => None, - // unreachable or can't be ZST - _ => Some(false), + // clearly not ZST + ty::Bool + | ty::Char + | ty::Int(..) + | ty::Uint(..) + | ty::Float(..) + | ty::RawPtr(..) + | ty::Ref(..) + | ty::FnPtr(..) => Some(false), + // check `layout_of` to see (including unreachable things we won't actually see) + _ => None, } } diff --git a/tests/mir-opt/instsimplify/simplify_repeat.repeat_once_to_aggregate.InstSimplify-after-simplifycfg.diff b/tests/mir-opt/instsimplify/simplify_repeat.repeat_once_to_aggregate.InstSimplify-after-simplifycfg.diff index a5e3ddbc57e..6c1b9abc5d7 100644 --- a/tests/mir-opt/instsimplify/simplify_repeat.repeat_once_to_aggregate.InstSimplify-after-simplifycfg.diff +++ b/tests/mir-opt/instsimplify/simplify_repeat.repeat_once_to_aggregate.InstSimplify-after-simplifycfg.diff @@ -4,13 +4,25 @@ fn repeat_once_to_aggregate(_1: T) -> [T; 1] { debug x => _1; let mut _0: [T; 1]; - let mut _2: T; + let _2: [T; 1]; + let mut _3: T; + let mut _4: T; + scope 1 { + debug other => _2; + } bb0: { StorageLive(_2); - _2 = copy _1; -- _0 = [move _2; 1]; -+ _0 = [move _2]; + StorageLive(_3); + _3 = copy _1; +- _2 = [move _3; 1]; ++ _2 = [move _3]; + StorageDead(_3); + StorageLive(_4); + _4 = copy _1; +- _0 = [move _4; 1]; ++ _0 = [move _4]; + StorageDead(_4); StorageDead(_2); return; } diff --git a/tests/mir-opt/instsimplify/simplify_repeat.rs b/tests/mir-opt/instsimplify/simplify_repeat.rs index 359f66710b2..abcdf32072b 100644 --- a/tests/mir-opt/instsimplify/simplify_repeat.rs +++ b/tests/mir-opt/instsimplify/simplify_repeat.rs @@ -2,12 +2,19 @@ //@ compile-flags: -C panic=abort #![crate_type = "lib"] +const MYSTERY: usize = 3_usize.pow(2) - 2_usize.pow(3); + // EMIT_MIR simplify_repeat.repeat_once_to_aggregate.InstSimplify-after-simplifycfg.diff pub fn repeat_once_to_aggregate<T: Copy>(x: T) -> [T; 1] { // CHECK-LABEL: fn repeat_once_to_aggregate( + // CHECK: debug other => [[OTHER:_[0-9]+]] + // CHECK-NOT: [move {{_[0-9]+}}; 1] + // CHECK: [[OTHER]] = [move {{_[0-9]+}}]; // CHECK-NOT: [move {{_[0-9]+}}; 1] // CHECK: _0 = [move {{_[0-9]+}}]; // CHECK-NOT: [move {{_[0-9]+}}; 1] + let other = [x; MYSTERY]; + [x; 1] } diff --git a/tests/mir-opt/remove_zsts.remove_generic_array.RemoveZsts.diff b/tests/mir-opt/remove_zsts.remove_generic_array.RemoveZsts.diff index 97ff88cc812..2ac944a6c6b 100644 --- a/tests/mir-opt/remove_zsts.remove_generic_array.RemoveZsts.diff +++ b/tests/mir-opt/remove_zsts.remove_generic_array.RemoveZsts.diff @@ -6,9 +6,15 @@ let mut _0: (); let _2: [T; 0]; let mut _3: T; + let mut _5: T; scope 1 { - debug a => _2; + debug a => const ZeroSized: [T; 0]; + let _4: [T; 0]; + scope 2 { +- debug b => _4; ++ debug b => const ZeroSized: [T; 0]; + } } bb0: { @@ -19,10 +25,19 @@ - _2 = []; + nop; StorageDead(_3); +- StorageLive(_4); ++ nop; + StorageLive(_5); + _5 = copy _1; +- _4 = []; ++ nop; + StorageDead(_5); - _0 = const (); +- StorageDead(_4); - StorageDead(_2); + nop; + nop; ++ nop; return; } } diff --git a/tests/mir-opt/remove_zsts.rs b/tests/mir-opt/remove_zsts.rs index d3db1c20142..baf9d8ece26 100644 --- a/tests/mir-opt/remove_zsts.rs +++ b/tests/mir-opt/remove_zsts.rs @@ -12,12 +12,17 @@ fn get_union() -> Foo { Foo { x: () } } +const MYSTERY: usize = 280_usize.isqrt() - 260_usize.isqrt(); + // EMIT_MIR remove_zsts.remove_generic_array.RemoveZsts.diff fn remove_generic_array<T: Copy>(x: T) { // CHECK-LABEL: fn remove_generic_array // CHECK: debug a => const ZeroSized: [T; 0]; + // CHECK: debug b => const ZeroSized: [T; 0]; // CHECK-NOT: = []; + // CHECK-NOT: ; 1] let a = [x; 0]; + let b = [x; MYSTERY]; } fn main() { |