diff --git a/compiler/rustc_middle/src/mir/terminator.rs b/compiler/rustc_middle/src/mir/terminator.rs index fdbbf468ecea2..ed29c2d30273f 100644 --- a/compiler/rustc_middle/src/mir/terminator.rs +++ b/compiler/rustc_middle/src/mir/terminator.rs @@ -74,6 +74,17 @@ impl SwitchTargets { pub fn target_for_value(&self, value: u128) -> BasicBlock { self.iter().find_map(|(v, t)| (v == value).then_some(t)).unwrap_or_else(|| self.otherwise()) } + + /// Adds a new target to the switch. But You cannot add an already present value. + #[inline] + pub fn add_target(&mut self, value: u128, bb: BasicBlock) { + let value = Pu128(value); + if self.values.contains(&value) { + bug!("target value {:?} already present", value); + } + self.values.push(value); + self.targets.insert(self.targets.len() - 1, bb); + } } pub struct SwitchTargetsIter<'a> { diff --git a/compiler/rustc_mir_transform/src/uninhabited_enum_branching.rs b/compiler/rustc_mir_transform/src/uninhabited_enum_branching.rs index e68d37f4c701e..dbe9ba08d7c55 100644 --- a/compiler/rustc_mir_transform/src/uninhabited_enum_branching.rs +++ b/compiler/rustc_mir_transform/src/uninhabited_enum_branching.rs @@ -78,6 +78,7 @@ impl<'tcx> MirPass<'tcx> for UninhabitedEnumBranching { trace!("UninhabitedEnumBranching starting for {:?}", body.source); let mut removable_switchs = Vec::new(); + let mut otherwise_is_last_variant_switchs = Vec::new(); for (bb, bb_data) in body.basic_blocks.iter_enumerated() { trace!("processing block {:?}", bb); @@ -92,7 +93,7 @@ impl<'tcx> MirPass<'tcx> for UninhabitedEnumBranching { tcx.param_env_reveal_all_normalized(body.source.def_id()).and(discriminant_ty), ); - let allowed_variants = if let Ok(layout) = layout { + let mut allowed_variants = if let Ok(layout) = layout { variant_discriminants(&layout, discriminant_ty, tcx) } else { continue; @@ -103,20 +104,29 @@ impl<'tcx> MirPass<'tcx> for UninhabitedEnumBranching { let terminator = bb_data.terminator(); let TerminatorKind::SwitchInt { targets, .. } = &terminator.kind else { bug!() }; - let mut reachable_count = 0; for (index, (val, _)) in targets.iter().enumerate() { - if allowed_variants.contains(&val) { - reachable_count += 1; - } else { + if !allowed_variants.remove(&val) { removable_switchs.push((bb, index)); } } - if reachable_count == allowed_variants.len() { + if allowed_variants.is_empty() { removable_switchs.push((bb, targets.iter().count())); + } else if allowed_variants.len() == 1 { + #[allow(rustc::potential_query_instability)] + let last_variant = *allowed_variants.iter().next().unwrap(); + otherwise_is_last_variant_switchs.push((bb, last_variant)); } } + for (bb, last_variant) in otherwise_is_last_variant_switchs { + let bb_data = &mut body.basic_blocks.as_mut()[bb]; + let terminator = bb_data.terminator_mut(); + let TerminatorKind::SwitchInt { targets, .. } = &mut terminator.kind else { bug!() }; + targets.add_target(last_variant, targets.otherwise()); + removable_switchs.push((bb, targets.iter().count())); + } + if removable_switchs.is_empty() { return; } diff --git a/tests/codegen/enum/uninhabited_enum_default_branch.rs b/tests/codegen/enum/uninhabited_enum_default_branch.rs new file mode 100644 index 0000000000000..0fada2e788643 --- /dev/null +++ b/tests/codegen/enum/uninhabited_enum_default_branch.rs @@ -0,0 +1,24 @@ +// compile-flags: -O + +#![crate_type = "lib"] + +#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord)] +pub struct Int(u32); + +const A: Int = Int(201); +const B: Int = Int(270); +const C: Int = Int(153); + +// CHECK-LABEL: @foo +// CHECK-SAME: [[TMP0:%.*]]) +// CHECK-NEXT: start: +// CHECK-NEXT: [[TMP1:%.*]] = add i32 [[TMP0]], -201 +// CHECK-NEXT: [[OR_COND:%.*]] = icmp ult i32 [[TMP1]], 70 +// CHECK-NEXT: [[TMP2:%.*]] = icmp eq i32 [[TMP0]], 153 +// CHECK-NEXT: [[SPEC_SELECT:%.*]] = or i1 [[OR_COND]], [[TMP2]] +// CHECK-NEXT: ret i1 [[SPEC_SELECT]] +#[no_mangle] +pub fn foo(x: Int) -> bool { + (x >= A && x <= B) + || x == C +} diff --git a/tests/mir-opt/funky_arms.float_to_exponential_common.GVN.panic-abort.diff b/tests/mir-opt/funky_arms.float_to_exponential_common.GVN.panic-abort.diff index 080478ea88419..bd346af6d16e4 100644 --- a/tests/mir-opt/funky_arms.float_to_exponential_common.GVN.panic-abort.diff +++ b/tests/mir-opt/funky_arms.float_to_exponential_common.GVN.panic-abort.diff @@ -69,7 +69,7 @@ StorageLive(_6); _6 = ((*_1).4: std::option::Option); _7 = discriminant(_6); - switchInt(move _7) -> [1: bb4, otherwise: bb6]; + switchInt(move _7) -> [1: bb4, 0: bb6, otherwise: bb9]; } bb4: { @@ -135,5 +135,9 @@ StorageDead(_6); return; } + + bb9: { + unreachable; + } } diff --git a/tests/mir-opt/funky_arms.float_to_exponential_common.GVN.panic-unwind.diff b/tests/mir-opt/funky_arms.float_to_exponential_common.GVN.panic-unwind.diff index ff8933fca8b2c..422cbeaa224ea 100644 --- a/tests/mir-opt/funky_arms.float_to_exponential_common.GVN.panic-unwind.diff +++ b/tests/mir-opt/funky_arms.float_to_exponential_common.GVN.panic-unwind.diff @@ -69,7 +69,7 @@ StorageLive(_6); _6 = ((*_1).4: std::option::Option); _7 = discriminant(_6); - switchInt(move _7) -> [1: bb4, otherwise: bb6]; + switchInt(move _7) -> [1: bb4, 0: bb6, otherwise: bb9]; } bb4: { @@ -135,5 +135,9 @@ StorageDead(_6); return; } + + bb9: { + unreachable; + } } diff --git a/tests/mir-opt/simplify_locals_fixedpoint.foo.SimplifyLocals-final.panic-abort.diff b/tests/mir-opt/simplify_locals_fixedpoint.foo.SimplifyLocals-final.panic-abort.diff index 1566d7197acd8..3108b7d3e13d7 100644 --- a/tests/mir-opt/simplify_locals_fixedpoint.foo.SimplifyLocals-final.panic-abort.diff +++ b/tests/mir-opt/simplify_locals_fixedpoint.foo.SimplifyLocals-final.panic-abort.diff @@ -23,7 +23,7 @@ StorageDead(_3); StorageDead(_2); _5 = discriminant((_1.0: std::option::Option)); - switchInt(move _5) -> [1: bb1, otherwise: bb3]; + switchInt(move _5) -> [1: bb1, 0: bb3, otherwise: bb5]; } bb1: { @@ -46,5 +46,9 @@ StorageDead(_1); return; } + + bb5: { + unreachable; + } } diff --git a/tests/mir-opt/simplify_locals_fixedpoint.foo.SimplifyLocals-final.panic-unwind.diff b/tests/mir-opt/simplify_locals_fixedpoint.foo.SimplifyLocals-final.panic-unwind.diff index ba5262b0ee143..3ef3be198ede3 100644 --- a/tests/mir-opt/simplify_locals_fixedpoint.foo.SimplifyLocals-final.panic-unwind.diff +++ b/tests/mir-opt/simplify_locals_fixedpoint.foo.SimplifyLocals-final.panic-unwind.diff @@ -23,7 +23,7 @@ StorageDead(_3); StorageDead(_2); _5 = discriminant((_1.0: std::option::Option)); - switchInt(move _5) -> [1: bb1, otherwise: bb3]; + switchInt(move _5) -> [1: bb1, 0: bb3, otherwise: bb5]; } bb1: { @@ -46,5 +46,9 @@ StorageDead(_1); return; } + + bb5: { + unreachable; + } } diff --git a/tests/mir-opt/uninhabited_enum_branching.otherwise_t1.UninhabitedEnumBranching.diff b/tests/mir-opt/uninhabited_enum_branching.otherwise_t1.UninhabitedEnumBranching.diff new file mode 100644 index 0000000000000..383fde4d787b9 --- /dev/null +++ b/tests/mir-opt/uninhabited_enum_branching.otherwise_t1.UninhabitedEnumBranching.diff @@ -0,0 +1,53 @@ +- // MIR for `otherwise_t1` before UninhabitedEnumBranching ++ // MIR for `otherwise_t1` after UninhabitedEnumBranching + + fn otherwise_t1() -> () { + let mut _0: (); + let _1: &str; + let mut _2: Test1; + let mut _3: isize; + let _4: &str; + let _5: &str; + + bb0: { + StorageLive(_1); + StorageLive(_2); + _2 = Test1::C; + _3 = discriminant(_2); +- switchInt(move _3) -> [0: bb2, 1: bb3, otherwise: bb1]; ++ switchInt(move _3) -> [0: bb5, 1: bb5, 2: bb1, otherwise: bb5]; + } + + bb1: { + StorageLive(_5); + _5 = const "C"; + _1 = &(*_5); + StorageDead(_5); + goto -> bb4; + } + + bb2: { + _1 = const "A(Empty)"; + goto -> bb4; + } + + bb3: { + StorageLive(_4); + _4 = const "B(Empty)"; + _1 = &(*_4); + StorageDead(_4); + goto -> bb4; + } + + bb4: { + StorageDead(_2); + StorageDead(_1); + _0 = const (); + return; ++ } ++ ++ bb5: { ++ unreachable; + } + } + diff --git a/tests/mir-opt/uninhabited_enum_branching.otherwise_t2.UninhabitedEnumBranching.diff b/tests/mir-opt/uninhabited_enum_branching.otherwise_t2.UninhabitedEnumBranching.diff new file mode 100644 index 0000000000000..3a2dc19db71cd --- /dev/null +++ b/tests/mir-opt/uninhabited_enum_branching.otherwise_t2.UninhabitedEnumBranching.diff @@ -0,0 +1,44 @@ +- // MIR for `otherwise_t2` before UninhabitedEnumBranching ++ // MIR for `otherwise_t2` after UninhabitedEnumBranching + + fn otherwise_t2() -> () { + let mut _0: (); + let _1: &str; + let mut _2: Test2; + let mut _3: isize; + let _4: &str; + + bb0: { + StorageLive(_1); + StorageLive(_2); + _2 = Test2::D; + _3 = discriminant(_2); +- switchInt(move _3) -> [4: bb2, otherwise: bb1]; ++ switchInt(move _3) -> [4: bb2, 5: bb1, otherwise: bb4]; + } + + bb1: { + StorageLive(_4); + _4 = const "E"; + _1 = &(*_4); + StorageDead(_4); + goto -> bb3; + } + + bb2: { + _1 = const "D"; + goto -> bb3; + } + + bb3: { + StorageDead(_2); + StorageDead(_1); + _0 = const (); + return; ++ } ++ ++ bb4: { ++ unreachable; + } + } + diff --git a/tests/mir-opt/uninhabited_enum_branching.otherwise_t3.UninhabitedEnumBranching.diff b/tests/mir-opt/uninhabited_enum_branching.otherwise_t3.UninhabitedEnumBranching.diff new file mode 100644 index 0000000000000..5dc1e2b73f6a4 --- /dev/null +++ b/tests/mir-opt/uninhabited_enum_branching.otherwise_t3.UninhabitedEnumBranching.diff @@ -0,0 +1,53 @@ +- // MIR for `otherwise_t3` before UninhabitedEnumBranching ++ // MIR for `otherwise_t3` after UninhabitedEnumBranching + + fn otherwise_t3() -> () { + let mut _0: (); + let _1: &str; + let mut _2: Test3; + let mut _3: isize; + let _4: &str; + let _5: &str; + + bb0: { + StorageLive(_1); + StorageLive(_2); + _2 = Test3::C; + _3 = discriminant(_2); +- switchInt(move _3) -> [0: bb2, 1: bb3, otherwise: bb1]; ++ switchInt(move _3) -> [0: bb5, 1: bb5, otherwise: bb1]; + } + + bb1: { + StorageLive(_5); + _5 = const "C"; + _1 = &(*_5); + StorageDead(_5); + goto -> bb4; + } + + bb2: { + _1 = const "A(Empty)"; + goto -> bb4; + } + + bb3: { + StorageLive(_4); + _4 = const "B(Empty)"; + _1 = &(*_4); + StorageDead(_4); + goto -> bb4; + } + + bb4: { + StorageDead(_2); + StorageDead(_1); + _0 = const (); + return; ++ } ++ ++ bb5: { ++ unreachable; + } + } + diff --git a/tests/mir-opt/uninhabited_enum_branching.otherwise_t4.UninhabitedEnumBranching.diff b/tests/mir-opt/uninhabited_enum_branching.otherwise_t4.UninhabitedEnumBranching.diff new file mode 100644 index 0000000000000..1352dda49715b --- /dev/null +++ b/tests/mir-opt/uninhabited_enum_branching.otherwise_t4.UninhabitedEnumBranching.diff @@ -0,0 +1,48 @@ +- // MIR for `otherwise_t4` before UninhabitedEnumBranching ++ // MIR for `otherwise_t4` after UninhabitedEnumBranching + + fn otherwise_t4() -> () { + let mut _0: (); + let _1: &str; + let mut _2: Test4; + let mut _3: isize; + let _4: &str; + let _5: &str; + + bb0: { + StorageLive(_1); + StorageLive(_2); + _2 = Test4::C; + _3 = discriminant(_2); + switchInt(move _3) -> [0: bb2, 1: bb3, otherwise: bb1]; + } + + bb1: { + StorageLive(_5); + _5 = const "CD"; + _1 = &(*_5); + StorageDead(_5); + goto -> bb4; + } + + bb2: { + _1 = const "A(i32)"; + goto -> bb4; + } + + bb3: { + StorageLive(_4); + _4 = const "B(i32)"; + _1 = &(*_4); + StorageDead(_4); + goto -> bb4; + } + + bb4: { + StorageDead(_2); + StorageDead(_1); + _0 = const (); + return; + } + } + diff --git a/tests/mir-opt/uninhabited_enum_branching.otherwise_t4_uninhabited_default.UninhabitedEnumBranching.diff b/tests/mir-opt/uninhabited_enum_branching.otherwise_t4_uninhabited_default.UninhabitedEnumBranching.diff new file mode 100644 index 0000000000000..40dd961fbac4d --- /dev/null +++ b/tests/mir-opt/uninhabited_enum_branching.otherwise_t4_uninhabited_default.UninhabitedEnumBranching.diff @@ -0,0 +1,62 @@ +- // MIR for `otherwise_t4_uninhabited_default` before UninhabitedEnumBranching ++ // MIR for `otherwise_t4_uninhabited_default` after UninhabitedEnumBranching + + fn otherwise_t4_uninhabited_default() -> () { + let mut _0: (); + let _1: &str; + let mut _2: Test4; + let mut _3: isize; + let _4: &str; + let _5: &str; + let _6: &str; + + bb0: { + StorageLive(_1); + StorageLive(_2); + _2 = Test4::C; + _3 = discriminant(_2); +- switchInt(move _3) -> [0: bb2, 1: bb3, 2: bb4, otherwise: bb1]; ++ switchInt(move _3) -> [0: bb2, 1: bb3, 2: bb4, 3: bb1, otherwise: bb6]; + } + + bb1: { + StorageLive(_6); + _6 = const "D"; + _1 = &(*_6); + StorageDead(_6); + goto -> bb5; + } + + bb2: { + _1 = const "A(i32)"; + goto -> bb5; + } + + bb3: { + StorageLive(_4); + _4 = const "B(i32)"; + _1 = &(*_4); + StorageDead(_4); + goto -> bb5; + } + + bb4: { + StorageLive(_5); + _5 = const "C"; + _1 = &(*_5); + StorageDead(_5); + goto -> bb5; + } + + bb5: { + StorageDead(_2); + StorageDead(_1); + _0 = const (); + return; ++ } ++ ++ bb6: { ++ unreachable; + } + } + diff --git a/tests/mir-opt/uninhabited_enum_branching.rs b/tests/mir-opt/uninhabited_enum_branching.rs index 60389117b1614..721740549d35f 100644 --- a/tests/mir-opt/uninhabited_enum_branching.rs +++ b/tests/mir-opt/uninhabited_enum_branching.rs @@ -23,6 +23,13 @@ enum Test3 { D, } +enum Test4 { + A(i32), + B(i32), + C, + D, +} + struct Plop { xx: u32, test3: Test3, @@ -42,6 +49,7 @@ fn simple() { }; } + // EMIT_MIR uninhabited_enum_branching.custom_discriminant.UninhabitedEnumBranching.diff fn custom_discriminant() { // CHECK-LABEL: fn custom_discriminant( @@ -55,6 +63,80 @@ fn custom_discriminant() { }; } +// EMIT_MIR uninhabited_enum_branching.otherwise_t1.UninhabitedEnumBranching.diff +#[no_mangle] +fn otherwise_t1() { + // CHECK-LABEL: fn otherwise_t1( + // CHECK: [[discr:_.*]] = discriminant( + // CHECK: switchInt(move [[discr]]) -> [0: bb5, 1: bb5, 2: bb1, otherwise: bb5]; + // CHECK: bb5: { + // CHECK-NEXT: unreachable; + match Test1::C { + Test1::A(_) => "A(Empty)", + Test1::B(_) => "B(Empty)", + _ => "C", + }; +} + +// EMIT_MIR uninhabited_enum_branching.otherwise_t2.UninhabitedEnumBranching.diff +fn otherwise_t2() { + // CHECK-LABEL: fn otherwise_t2( + // CHECK: [[discr:_.*]] = discriminant( + // CHECK: switchInt(move [[discr]]) -> [4: bb2, 5: bb1, otherwise: bb4]; + // CHECK: bb4: { + // CHECK-NEXT: unreachable; + match Test2::D { + Test2::D => "D", + _ => "E", + }; +} + +// EMIT_MIR uninhabited_enum_branching.otherwise_t3.UninhabitedEnumBranching.diff +fn otherwise_t3() { + // CHECK-LABEL: fn otherwise_t3( + // CHECK: [[discr:_.*]] = discriminant( + // CHECK: switchInt(move [[discr]]) -> [0: bb5, 1: bb5, otherwise: bb1]; + // CHECK: bb1: { + // CHECK-NOT: unreachable; + // CHECK: } + // CHECK: bb5: { + // CHECK-NEXT: unreachable; + match Test3::C { + Test3::A(_) => "A(Empty)", + Test3::B(_) => "B(Empty)", + _ => "C", + }; +} + +// EMIT_MIR uninhabited_enum_branching.otherwise_t4_uninhabited_default.UninhabitedEnumBranching.diff +fn otherwise_t4_uninhabited_default() { + // CHECK-LABEL: fn otherwise_t4_uninhabited_default( + // CHECK: [[discr:_.*]] = discriminant( + // CHECK: switchInt(move [[discr]]) -> [0: bb2, 1: bb3, 2: bb4, 3: bb1, otherwise: bb6]; + // CHECK: bb6: { + // CHECK-NEXT: unreachable; + match Test4::C { + Test4::A(_) => "A(i32)", + Test4::B(_) => "B(i32)", + Test4::C => "C", + _ => "D", + }; +} + +// EMIT_MIR uninhabited_enum_branching.otherwise_t4.UninhabitedEnumBranching.diff +fn otherwise_t4() { + // CHECK-LABEL: fn otherwise_t4( + // CHECK: [[discr:_.*]] = discriminant( + // CHECK: switchInt(move [[discr]]) -> [0: bb2, 1: bb3, otherwise: bb1]; + // CHECK: bb1: { + // CHECK-NOT: unreachable; + // CHECK: } + match Test4::C { + Test4::A(_) => "A(i32)", + Test4::B(_) => "B(i32)", + _ => "CD", + }; +} // EMIT_MIR uninhabited_enum_branching.byref.UninhabitedEnumBranching.diff fn byref() { // CHECK-LABEL: fn byref( @@ -85,5 +167,10 @@ fn byref() { fn main() { simple(); custom_discriminant(); + otherwise_t1(); + otherwise_t2(); + otherwise_t3(); + otherwise_t4_uninhabited_default(); + otherwise_t4(); byref(); } diff --git a/tests/mir-opt/uninhabited_fallthrough_elimination.keep_fallthrough.UninhabitedEnumBranching.diff b/tests/mir-opt/uninhabited_fallthrough_elimination.keep_fallthrough.UninhabitedEnumBranching.diff index 79948139f888d..28a8c251d956a 100644 --- a/tests/mir-opt/uninhabited_fallthrough_elimination.keep_fallthrough.UninhabitedEnumBranching.diff +++ b/tests/mir-opt/uninhabited_fallthrough_elimination.keep_fallthrough.UninhabitedEnumBranching.diff @@ -9,7 +9,7 @@ bb0: { _2 = discriminant(_1); - switchInt(move _2) -> [0: bb2, 1: bb3, otherwise: bb1]; -+ switchInt(move _2) -> [0: bb5, 1: bb3, otherwise: bb1]; ++ switchInt(move _2) -> [0: bb5, 1: bb3, 2: bb1, otherwise: bb5]; } bb1: {