diff --git a/src/librustc_mir/transform/const_prop.rs b/src/librustc_mir/transform/const_prop.rs index ed02ef566a6..b5c2fa24e64 100644 --- a/src/librustc_mir/transform/const_prop.rs +++ b/src/librustc_mir/transform/const_prop.rs @@ -326,6 +326,8 @@ struct ConstPropagator<'mir, 'tcx> { // Because we have `MutVisitor` we can't obtain the `SourceInfo` from a `Location`. So we store // the last known `SourceInfo` here and just keep revisiting it. source_info: Option, + // Locals we need to forget at the end of the current block + locals_of_current_block: BitSet, } impl<'mir, 'tcx> LayoutOf for ConstPropagator<'mir, 'tcx> { @@ -395,6 +397,7 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> { //FIXME(wesleywiser) we can't steal this because `Visitor::super_visit_body()` needs it local_decls: body.local_decls.clone(), source_info: None, + locals_of_current_block: BitSet::new_empty(body.local_decls.len()), } } @@ -409,8 +412,10 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> { } } - fn remove_const(&mut self, local: Local) { - self.ecx.frame_mut().locals[local] = + /// Remove `local` from the pool of `Locals`. Allows writing to them, + /// but not reading from them anymore. + fn remove_const(ecx: &mut InterpCx<'mir, 'tcx, ConstPropMachine<'mir, 'tcx>>, local: Local) { + ecx.frame_mut().locals[local] = LocalState { value: LocalValue::Uninitialized, layout: Cell::new(None) }; } @@ -756,6 +761,8 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> { enum ConstPropMode { /// The `Local` can be propagated into and reads of this `Local` can also be propagated. FullConstProp, + /// The `Local` can only be propagated into and from its own block. + OnlyInsideOwnBlock, /// The `Local` can be propagated into but reads cannot be propagated. OnlyPropagateInto, /// No propagation is allowed at all. @@ -787,10 +794,18 @@ impl CanConstProp { // lint for x != y // FIXME(oli-obk): lint variables until they are used in a condition // FIXME(oli-obk): lint if return value is constant - if cpv.local_kinds[local] == LocalKind::Arg || cpv.local_kinds[local] == LocalKind::Var - { + if cpv.local_kinds[local] == LocalKind::Arg { *val = ConstPropMode::OnlyPropagateInto; - trace!("local {:?} can't be const propagated because it's not a temporary", local); + trace!( + "local {:?} can't be const propagated because it's a function argument", + local + ); + } else if cpv.local_kinds[local] == LocalKind::Var { + *val = ConstPropMode::OnlyInsideOwnBlock; + trace!( + "local {:?} will only be propagated inside its block, because it's a user variable", + local + ); } } cpv.visit_body(&body); @@ -858,25 +873,35 @@ impl<'mir, 'tcx> MutVisitor<'tcx> for ConstPropagator<'mir, 'tcx> { if let Some(local) = place.as_local() { let can_const_prop = self.can_const_prop[local]; if let Some(()) = self.const_prop(rval, place_layout, source_info, place) { - if can_const_prop == ConstPropMode::FullConstProp - || can_const_prop == ConstPropMode::OnlyPropagateInto - { + if can_const_prop != ConstPropMode::NoPropagation { + // This will return None for Locals that are from other blocks, + // so it should be okay to propagate from here on down. if let Some(value) = self.get_const(local) { if self.should_const_prop(value) { trace!("replacing {:?} with {:?}", rval, value); self.replace_with_const(rval, value, statement.source_info); - - if can_const_prop == ConstPropMode::FullConstProp { + if can_const_prop == ConstPropMode::FullConstProp + || can_const_prop == ConstPropMode::OnlyInsideOwnBlock + { trace!("propagated into {:?}", local); } } + if can_const_prop == ConstPropMode::OnlyInsideOwnBlock { + trace!( + "found local restricted to its block. Will remove it from const-prop after block is finished. Local: {:?}", + local + ); + self.locals_of_current_block.insert(local); + } } } } - if self.can_const_prop[local] != ConstPropMode::FullConstProp { + if self.can_const_prop[local] == ConstPropMode::OnlyPropagateInto + || self.can_const_prop[local] == ConstPropMode::NoPropagation + { trace!("can't propagate into {:?}", local); if local != RETURN_PLACE { - self.remove_const(local); + Self::remove_const(&mut self.ecx, local); } } } @@ -915,7 +940,7 @@ impl<'mir, 'tcx> MutVisitor<'tcx> for ConstPropagator<'mir, 'tcx> { // doesn't use the invalid value match cond { Operand::Move(ref place) | Operand::Copy(ref place) => { - self.remove_const(place.local); + Self::remove_const(&mut self.ecx, place.local); } Operand::Constant(_) => {} } @@ -992,5 +1017,13 @@ impl<'mir, 'tcx> MutVisitor<'tcx> for ConstPropagator<'mir, 'tcx> { //FIXME(wesleywiser) Call does have Operands that could be const-propagated TerminatorKind::Call { .. } => {} } + // We remove all Locals which are restricted in propagation to their containing blocks. + // We wouldn't need to clone, but the borrow checker can't see that we're not aliasing + // the locals_of_current_block field, so we need to clone it first. + // let ecx = &mut self.ecx; + for local in self.locals_of_current_block.iter() { + Self::remove_const(&mut self.ecx, local); + } + self.locals_of_current_block.clear(); } } diff --git a/src/test/mir-opt/const_prop/scalar_literal_propagation/rustc.main.ConstProp.diff b/src/test/mir-opt/const_prop/scalar_literal_propagation/rustc.main.ConstProp.diff index f872696cf94..0183ff7716c 100644 --- a/src/test/mir-opt/const_prop/scalar_literal_propagation/rustc.main.ConstProp.diff +++ b/src/test/mir-opt/const_prop/scalar_literal_propagation/rustc.main.ConstProp.diff @@ -21,7 +21,14 @@ // + literal: Const { ty: u32, val: Value(Scalar(0x00000001)) } StorageLive(_2); // scope 1 at $DIR/scalar_literal_propagation.rs:4:5: 4:15 StorageLive(_3); // scope 1 at $DIR/scalar_literal_propagation.rs:4:13: 4:14 - _3 = _1; // scope 1 at $DIR/scalar_literal_propagation.rs:4:13: 4:14 +- _3 = _1; // scope 1 at $DIR/scalar_literal_propagation.rs:4:13: 4:14 ++ _3 = const 1u32; // scope 1 at $DIR/scalar_literal_propagation.rs:4:13: 4:14 ++ // ty::Const ++ // + ty: u32 ++ // + val: Value(Scalar(0x00000001)) ++ // mir::Constant ++ // + span: $DIR/scalar_literal_propagation.rs:4:13: 4:14 ++ // + literal: Const { ty: u32, val: Value(Scalar(0x00000001)) } _2 = const consume(move _3) -> bb1; // scope 1 at $DIR/scalar_literal_propagation.rs:4:5: 4:15 // ty::Const // + ty: fn(u32) {consume} diff --git a/src/test/mir-opt/const_prop/tuple_literal_propagation/rustc.main.ConstProp.diff b/src/test/mir-opt/const_prop/tuple_literal_propagation/rustc.main.ConstProp.diff index f57b7f78d99..1511b361f58 100644 --- a/src/test/mir-opt/const_prop/tuple_literal_propagation/rustc.main.ConstProp.diff +++ b/src/test/mir-opt/const_prop/tuple_literal_propagation/rustc.main.ConstProp.diff @@ -29,7 +29,20 @@ // + literal: Const { ty: u32, val: Value(Scalar(0x00000002)) } StorageLive(_2); // scope 1 at $DIR/tuple_literal_propagation.rs:5:5: 5:15 StorageLive(_3); // scope 1 at $DIR/tuple_literal_propagation.rs:5:13: 5:14 - _3 = _1; // scope 1 at $DIR/tuple_literal_propagation.rs:5:13: 5:14 +- _3 = _1; // scope 1 at $DIR/tuple_literal_propagation.rs:5:13: 5:14 ++ _3 = (const 1u32, const 2u32); // scope 1 at $DIR/tuple_literal_propagation.rs:5:13: 5:14 ++ // ty::Const ++ // + ty: u32 ++ // + val: Value(Scalar(0x00000001)) ++ // mir::Constant ++ // + span: $DIR/tuple_literal_propagation.rs:5:13: 5:14 ++ // + literal: Const { ty: u32, val: Value(Scalar(0x00000001)) } ++ // ty::Const ++ // + ty: u32 ++ // + val: Value(Scalar(0x00000002)) ++ // mir::Constant ++ // + span: $DIR/tuple_literal_propagation.rs:5:13: 5:14 ++ // + literal: Const { ty: u32, val: Value(Scalar(0x00000002)) } _2 = const consume(move _3) -> bb1; // scope 1 at $DIR/tuple_literal_propagation.rs:5:5: 5:15 // ty::Const // + ty: fn((u32, u32)) {consume} diff --git a/src/test/mir-opt/simplify-arm-identity.rs b/src/test/mir-opt/simplify-arm-identity.rs index cc6aab7523f..24e91b3ff61 100644 --- a/src/test/mir-opt/simplify-arm-identity.rs +++ b/src/test/mir-opt/simplify-arm-identity.rs @@ -2,6 +2,7 @@ // Regression test for issue #66856. // // compile-flags: -Zmir-opt-level=2 +// EMIT_MIR_FOR_EACH_BIT_WIDTH enum Src { Foo(u8), diff --git a/src/test/mir-opt/simplify-arm-identity/32bit/rustc.main.SimplifyArmIdentity.diff b/src/test/mir-opt/simplify-arm-identity/32bit/rustc.main.SimplifyArmIdentity.diff new file mode 100644 index 00000000000..bf24bfb2c57 --- /dev/null +++ b/src/test/mir-opt/simplify-arm-identity/32bit/rustc.main.SimplifyArmIdentity.diff @@ -0,0 +1,53 @@ +- // MIR for `main` before SimplifyArmIdentity ++ // MIR for `main` after SimplifyArmIdentity + + fn main() -> () { + let mut _0: (); // return place in scope 0 at $DIR/simplify-arm-identity.rs:17:11: 17:11 + let _1: Src as UserTypeProjection { base: UserType(0), projs: [] }; // in scope 0 at $DIR/simplify-arm-identity.rs:18:9: 18:10 + let mut _2: Dst; // in scope 0 at $DIR/simplify-arm-identity.rs:19:18: 22:6 + let mut _3: isize; // in scope 0 at $DIR/simplify-arm-identity.rs:20:9: 20:20 + let mut _5: u8; // in scope 0 at $DIR/simplify-arm-identity.rs:20:33: 20:34 + scope 1 { + debug e => _1; // in scope 1 at $DIR/simplify-arm-identity.rs:18:9: 18:10 + let _4: u8; // in scope 1 at $DIR/simplify-arm-identity.rs:20:18: 20:19 + scope 2 { + } + scope 3 { + debug x => _4; // in scope 3 at $DIR/simplify-arm-identity.rs:20:18: 20:19 + } + } + + bb0: { + StorageLive(_1); // scope 0 at $DIR/simplify-arm-identity.rs:18:9: 18:10 + ((_1 as Foo).0: u8) = const 0u8; // scope 0 at $DIR/simplify-arm-identity.rs:18:18: 18:29 + // ty::Const + // + ty: u8 + // + val: Value(Scalar(0x00)) + // mir::Constant + // + span: $DIR/simplify-arm-identity.rs:18:27: 18:28 + // + literal: Const { ty: u8, val: Value(Scalar(0x00)) } + discriminant(_1) = 0; // scope 0 at $DIR/simplify-arm-identity.rs:18:18: 18:29 + StorageLive(_2); // scope 1 at $DIR/simplify-arm-identity.rs:19:18: 22:6 + _3 = const 0isize; // scope 1 at $DIR/simplify-arm-identity.rs:20:9: 20:20 + // ty::Const + // + ty: isize + // + val: Value(Scalar(0x00000000)) + // mir::Constant + // + span: $DIR/simplify-arm-identity.rs:20:9: 20:20 + // + literal: Const { ty: isize, val: Value(Scalar(0x00000000)) } + _4 = ((_1 as Foo).0: u8); // scope 1 at $DIR/simplify-arm-identity.rs:20:18: 20:19 + ((_2 as Foo).0: u8) = move _4; // scope 3 at $DIR/simplify-arm-identity.rs:20:24: 20:35 + discriminant(_2) = 0; // scope 3 at $DIR/simplify-arm-identity.rs:20:24: 20:35 + StorageDead(_2); // scope 1 at $DIR/simplify-arm-identity.rs:22:6: 22:7 + _0 = const (); // scope 0 at $DIR/simplify-arm-identity.rs:17:11: 23:2 + // ty::Const + // + ty: () + // + val: Value(Scalar()) + // mir::Constant + // + span: $DIR/simplify-arm-identity.rs:17:11: 23:2 + // + literal: Const { ty: (), val: Value(Scalar()) } + StorageDead(_1); // scope 0 at $DIR/simplify-arm-identity.rs:23:1: 23:2 + return; // scope 0 at $DIR/simplify-arm-identity.rs:23:2: 23:2 + } + } + diff --git a/src/test/mir-opt/simplify-arm-identity/64bit/rustc.main.SimplifyArmIdentity.diff b/src/test/mir-opt/simplify-arm-identity/64bit/rustc.main.SimplifyArmIdentity.diff new file mode 100644 index 00000000000..ff7183e57d2 --- /dev/null +++ b/src/test/mir-opt/simplify-arm-identity/64bit/rustc.main.SimplifyArmIdentity.diff @@ -0,0 +1,53 @@ +- // MIR for `main` before SimplifyArmIdentity ++ // MIR for `main` after SimplifyArmIdentity + + fn main() -> () { + let mut _0: (); // return place in scope 0 at $DIR/simplify-arm-identity.rs:17:11: 17:11 + let _1: Src as UserTypeProjection { base: UserType(0), projs: [] }; // in scope 0 at $DIR/simplify-arm-identity.rs:18:9: 18:10 + let mut _2: Dst; // in scope 0 at $DIR/simplify-arm-identity.rs:19:18: 22:6 + let mut _3: isize; // in scope 0 at $DIR/simplify-arm-identity.rs:20:9: 20:20 + let mut _5: u8; // in scope 0 at $DIR/simplify-arm-identity.rs:20:33: 20:34 + scope 1 { + debug e => _1; // in scope 1 at $DIR/simplify-arm-identity.rs:18:9: 18:10 + let _4: u8; // in scope 1 at $DIR/simplify-arm-identity.rs:20:18: 20:19 + scope 2 { + } + scope 3 { + debug x => _4; // in scope 3 at $DIR/simplify-arm-identity.rs:20:18: 20:19 + } + } + + bb0: { + StorageLive(_1); // scope 0 at $DIR/simplify-arm-identity.rs:18:9: 18:10 + ((_1 as Foo).0: u8) = const 0u8; // scope 0 at $DIR/simplify-arm-identity.rs:18:18: 18:29 + // ty::Const + // + ty: u8 + // + val: Value(Scalar(0x00)) + // mir::Constant + // + span: $DIR/simplify-arm-identity.rs:18:27: 18:28 + // + literal: Const { ty: u8, val: Value(Scalar(0x00)) } + discriminant(_1) = 0; // scope 0 at $DIR/simplify-arm-identity.rs:18:18: 18:29 + StorageLive(_2); // scope 1 at $DIR/simplify-arm-identity.rs:19:18: 22:6 + _3 = const 0isize; // scope 1 at $DIR/simplify-arm-identity.rs:20:9: 20:20 + // ty::Const + // + ty: isize + // + val: Value(Scalar(0x0000000000000000)) + // mir::Constant + // + span: $DIR/simplify-arm-identity.rs:20:9: 20:20 + // + literal: Const { ty: isize, val: Value(Scalar(0x0000000000000000)) } + _4 = ((_1 as Foo).0: u8); // scope 1 at $DIR/simplify-arm-identity.rs:20:18: 20:19 + ((_2 as Foo).0: u8) = move _4; // scope 3 at $DIR/simplify-arm-identity.rs:20:24: 20:35 + discriminant(_2) = 0; // scope 3 at $DIR/simplify-arm-identity.rs:20:24: 20:35 + StorageDead(_2); // scope 1 at $DIR/simplify-arm-identity.rs:22:6: 22:7 + _0 = const (); // scope 0 at $DIR/simplify-arm-identity.rs:17:11: 23:2 + // ty::Const + // + ty: () + // + val: Value(Scalar()) + // mir::Constant + // + span: $DIR/simplify-arm-identity.rs:17:11: 23:2 + // + literal: Const { ty: (), val: Value(Scalar()) } + StorageDead(_1); // scope 0 at $DIR/simplify-arm-identity.rs:23:1: 23:2 + return; // scope 0 at $DIR/simplify-arm-identity.rs:23:2: 23:2 + } + } + diff --git a/src/test/mir-opt/simplify_match/rustc.main.SimplifyBranches-after-copy-prop.diff b/src/test/mir-opt/simplify_match/rustc.main.SimplifyBranches-after-copy-prop.diff index 68b1b70c52a..ae6dfae30b9 100644 --- a/src/test/mir-opt/simplify_match/rustc.main.SimplifyBranches-after-copy-prop.diff +++ b/src/test/mir-opt/simplify_match/rustc.main.SimplifyBranches-after-copy-prop.diff @@ -10,19 +10,24 @@ } bb0: { - nop; // scope 0 at $DIR/simplify_match.rs:6:11: 6:31 - nop; // scope 0 at $DIR/simplify_match.rs:6:17: 6:18 - nop; // scope 0 at $DIR/simplify_match.rs:6:21: 6:26 - nop; // scope 1 at $DIR/simplify_match.rs:6:28: 6:29 - nop; // scope 0 at $DIR/simplify_match.rs:6:30: 6:31 -- switchInt(const false) -> [false: bb1, otherwise: bb2]; // scope 0 at $DIR/simplify_match.rs:7:9: 7:13 -- // ty::Const -- // + ty: bool -- // + val: Value(Scalar(0x00)) -- // mir::Constant -- // + span: $DIR/simplify_match.rs:6:21: 6:26 -- // + literal: Const { ty: bool, val: Value(Scalar(0x00)) } -+ goto -> bb1; // scope 0 at $DIR/simplify_match.rs:7:9: 7:13 + StorageLive(_1); // scope 0 at $DIR/simplify_match.rs:6:11: 6:31 + StorageLive(_2); // scope 0 at $DIR/simplify_match.rs:6:17: 6:18 + _2 = const false; // scope 0 at $DIR/simplify_match.rs:6:21: 6:26 + // ty::Const + // + ty: bool + // + val: Value(Scalar(0x00)) + // mir::Constant + // + span: $DIR/simplify_match.rs:6:21: 6:26 + // + literal: Const { ty: bool, val: Value(Scalar(0x00)) } + _1 = const false; // scope 1 at $DIR/simplify_match.rs:6:28: 6:29 + // ty::Const + // + ty: bool + // + val: Value(Scalar(0x00)) + // mir::Constant + // + span: $DIR/simplify_match.rs:6:28: 6:29 + // + literal: Const { ty: bool, val: Value(Scalar(0x00)) } + StorageDead(_2); // scope 0 at $DIR/simplify_match.rs:6:30: 6:31 + goto -> bb1; // scope 0 at $DIR/simplify_match.rs:7:9: 7:13 } bb1: { @@ -47,7 +52,7 @@ } bb3: { - nop; // scope 0 at $DIR/simplify_match.rs:10:1: 10:2 + StorageDead(_1); // scope 0 at $DIR/simplify_match.rs:10:1: 10:2 return; // scope 0 at $DIR/simplify_match.rs:10:2: 10:2 } } diff --git a/src/test/run-fail/divide-by-zero.rs b/src/test/run-fail/divide-by-zero.rs index fdb3f4842e5..ba93563154a 100644 --- a/src/test/run-fail/divide-by-zero.rs +++ b/src/test/run-fail/divide-by-zero.rs @@ -1,5 +1,5 @@ // error-pattern:attempt to divide by zero - +#[allow(unconditional_panic)] fn main() { let y = 0; let _z = 1 / y; diff --git a/src/test/run-fail/dst-raw-slice.rs b/src/test/run-fail/dst-raw-slice.rs index 561b1fb42ed..2575de7cc58 100644 --- a/src/test/run-fail/dst-raw-slice.rs +++ b/src/test/run-fail/dst-raw-slice.rs @@ -1,6 +1,6 @@ // Test bounds checking for DST raw slices // error-pattern:index out of bounds - +#[allow(unconditional_panic)] fn main() { let a: *const [_] = &[1, 2, 3]; unsafe { diff --git a/src/test/run-fail/mod-zero.rs b/src/test/run-fail/mod-zero.rs index ac2959fcd38..f70b3ac920c 100644 --- a/src/test/run-fail/mod-zero.rs +++ b/src/test/run-fail/mod-zero.rs @@ -1,5 +1,5 @@ // error-pattern:attempt to calculate the remainder with a divisor of zero - +#[allow(unconditional_panic)] fn main() { let y = 0; let _z = 1 % y;