diff options
15 files changed, 96 insertions, 52 deletions
diff --git a/compiler/rustc_mir_transform/src/gvn.rs b/compiler/rustc_mir_transform/src/gvn.rs index 699b218d46d..afc75ff1313 100644 --- a/compiler/rustc_mir_transform/src/gvn.rs +++ b/compiler/rustc_mir_transform/src/gvn.rs @@ -776,10 +776,7 @@ impl<'body, 'tcx> VnState<'body, 'tcx> { } // Operations. - Rvalue::Len(ref mut place) => { - let place = self.simplify_place_value(place, location)?; - Value::Len(place) - } + Rvalue::Len(ref mut place) => return self.simplify_len(place, location), Rvalue::Cast(kind, ref mut value, to) => { let from = value.ty(self.local_decls, self.tcx); let value = self.simplify_operand(value, location)?; @@ -1021,6 +1018,39 @@ impl<'body, 'tcx> VnState<'body, 'tcx> { Some(result) } } + + fn simplify_len(&mut self, place: &mut Place<'tcx>, location: Location) -> Option<VnIndex> { + // Trivial case: we are fetching a statically known length. + let place_ty = place.ty(self.local_decls, self.tcx).ty; + if let ty::Array(_, len) = place_ty.kind() { + return self.insert_constant(Const::from_ty_const(*len, self.tcx)); + } + + let mut inner = self.simplify_place_value(place, location)?; + + // The length information is stored in the fat pointer. + // Reborrowing copies length information from one pointer to the other. + while let Value::Address { place: borrowed, .. } = self.get(inner) + && let [PlaceElem::Deref] = borrowed.projection[..] + && let Some(borrowed) = self.locals[borrowed.local] + { + inner = borrowed; + } + + // We have an unsizing cast, which assigns the length to fat pointer metadata. + if let Value::Cast { kind, from, to, .. } = self.get(inner) + && let CastKind::PointerCoercion(ty::adjustment::PointerCoercion::Unsize) = kind + && let Some(from) = from.builtin_deref(true) + && let ty::Array(_, len) = from.ty.kind() + && let Some(to) = to.builtin_deref(true) + && let ty::Slice(..) = to.ty.kind() + { + return self.insert_constant(Const::from_ty_const(*len, self.tcx)); + } + + // Fallback: a symbolic `Len`. + Some(self.insert(Value::Len(inner))) + } } fn op_to_prop_const<'tcx>( diff --git a/tests/mir-opt/const_prop/array_index.main.GVN.32bit.panic-abort.diff b/tests/mir-opt/const_prop/array_index.main.GVN.32bit.panic-abort.diff index f9537661e8c..6d00dd5b212 100644 --- a/tests/mir-opt/const_prop/array_index.main.GVN.32bit.panic-abort.diff +++ b/tests/mir-opt/const_prop/array_index.main.GVN.32bit.panic-abort.diff @@ -18,11 +18,12 @@ _2 = [const 0_u32, const 1_u32, const 2_u32, const 3_u32]; StorageLive(_3); _3 = const 2_usize; - _4 = Len(_2); +- _4 = Len(_2); - _5 = Lt(_3, _4); - assert(move _5, "index out of bounds: the length is {} but the index is {}", move _4, _3) -> [success: bb1, unwind unreachable]; -+ _5 = Lt(const 2_usize, _4); -+ assert(move _5, "index out of bounds: the length is {} but the index is {}", move _4, const 2_usize) -> [success: bb1, unwind unreachable]; ++ _4 = const 4_usize; ++ _5 = const true; ++ assert(const true, "index out of bounds: the length is {} but the index is {}", const 4_usize, const 2_usize) -> [success: bb1, unwind unreachable]; } bb1: { diff --git a/tests/mir-opt/const_prop/array_index.main.GVN.32bit.panic-unwind.diff b/tests/mir-opt/const_prop/array_index.main.GVN.32bit.panic-unwind.diff index 07886779fea..7e2f72ab31b 100644 --- a/tests/mir-opt/const_prop/array_index.main.GVN.32bit.panic-unwind.diff +++ b/tests/mir-opt/const_prop/array_index.main.GVN.32bit.panic-unwind.diff @@ -18,11 +18,12 @@ _2 = [const 0_u32, const 1_u32, const 2_u32, const 3_u32]; StorageLive(_3); _3 = const 2_usize; - _4 = Len(_2); +- _4 = Len(_2); - _5 = Lt(_3, _4); - assert(move _5, "index out of bounds: the length is {} but the index is {}", move _4, _3) -> [success: bb1, unwind continue]; -+ _5 = Lt(const 2_usize, _4); -+ assert(move _5, "index out of bounds: the length is {} but the index is {}", move _4, const 2_usize) -> [success: bb1, unwind continue]; ++ _4 = const 4_usize; ++ _5 = const true; ++ assert(const true, "index out of bounds: the length is {} but the index is {}", const 4_usize, const 2_usize) -> [success: bb1, unwind continue]; } bb1: { diff --git a/tests/mir-opt/const_prop/array_index.main.GVN.64bit.panic-abort.diff b/tests/mir-opt/const_prop/array_index.main.GVN.64bit.panic-abort.diff index f9537661e8c..6d00dd5b212 100644 --- a/tests/mir-opt/const_prop/array_index.main.GVN.64bit.panic-abort.diff +++ b/tests/mir-opt/const_prop/array_index.main.GVN.64bit.panic-abort.diff @@ -18,11 +18,12 @@ _2 = [const 0_u32, const 1_u32, const 2_u32, const 3_u32]; StorageLive(_3); _3 = const 2_usize; - _4 = Len(_2); +- _4 = Len(_2); - _5 = Lt(_3, _4); - assert(move _5, "index out of bounds: the length is {} but the index is {}", move _4, _3) -> [success: bb1, unwind unreachable]; -+ _5 = Lt(const 2_usize, _4); -+ assert(move _5, "index out of bounds: the length is {} but the index is {}", move _4, const 2_usize) -> [success: bb1, unwind unreachable]; ++ _4 = const 4_usize; ++ _5 = const true; ++ assert(const true, "index out of bounds: the length is {} but the index is {}", const 4_usize, const 2_usize) -> [success: bb1, unwind unreachable]; } bb1: { diff --git a/tests/mir-opt/const_prop/array_index.main.GVN.64bit.panic-unwind.diff b/tests/mir-opt/const_prop/array_index.main.GVN.64bit.panic-unwind.diff index 07886779fea..7e2f72ab31b 100644 --- a/tests/mir-opt/const_prop/array_index.main.GVN.64bit.panic-unwind.diff +++ b/tests/mir-opt/const_prop/array_index.main.GVN.64bit.panic-unwind.diff @@ -18,11 +18,12 @@ _2 = [const 0_u32, const 1_u32, const 2_u32, const 3_u32]; StorageLive(_3); _3 = const 2_usize; - _4 = Len(_2); +- _4 = Len(_2); - _5 = Lt(_3, _4); - assert(move _5, "index out of bounds: the length is {} but the index is {}", move _4, _3) -> [success: bb1, unwind continue]; -+ _5 = Lt(const 2_usize, _4); -+ assert(move _5, "index out of bounds: the length is {} but the index is {}", move _4, const 2_usize) -> [success: bb1, unwind continue]; ++ _4 = const 4_usize; ++ _5 = const true; ++ assert(const true, "index out of bounds: the length is {} but the index is {}", const 4_usize, const 2_usize) -> [success: bb1, unwind continue]; } bb1: { diff --git a/tests/mir-opt/const_prop/large_array_index.main.GVN.32bit.panic-abort.diff b/tests/mir-opt/const_prop/large_array_index.main.GVN.32bit.panic-abort.diff index cf36109fdcb..bd987c01ab1 100644 --- a/tests/mir-opt/const_prop/large_array_index.main.GVN.32bit.panic-abort.diff +++ b/tests/mir-opt/const_prop/large_array_index.main.GVN.32bit.panic-abort.diff @@ -18,11 +18,12 @@ _2 = [const 0_u8; 5000]; StorageLive(_3); _3 = const 2_usize; - _4 = Len(_2); +- _4 = Len(_2); - _5 = Lt(_3, _4); - assert(move _5, "index out of bounds: the length is {} but the index is {}", move _4, _3) -> [success: bb1, unwind unreachable]; -+ _5 = Lt(const 2_usize, _4); -+ assert(move _5, "index out of bounds: the length is {} but the index is {}", move _4, const 2_usize) -> [success: bb1, unwind unreachable]; ++ _4 = const 5000_usize; ++ _5 = const true; ++ assert(const true, "index out of bounds: the length is {} but the index is {}", const 5000_usize, const 2_usize) -> [success: bb1, unwind unreachable]; } bb1: { diff --git a/tests/mir-opt/const_prop/large_array_index.main.GVN.32bit.panic-unwind.diff b/tests/mir-opt/const_prop/large_array_index.main.GVN.32bit.panic-unwind.diff index 40ed9697180..e9ebef84ae0 100644 --- a/tests/mir-opt/const_prop/large_array_index.main.GVN.32bit.panic-unwind.diff +++ b/tests/mir-opt/const_prop/large_array_index.main.GVN.32bit.panic-unwind.diff @@ -18,11 +18,12 @@ _2 = [const 0_u8; 5000]; StorageLive(_3); _3 = const 2_usize; - _4 = Len(_2); +- _4 = Len(_2); - _5 = Lt(_3, _4); - assert(move _5, "index out of bounds: the length is {} but the index is {}", move _4, _3) -> [success: bb1, unwind continue]; -+ _5 = Lt(const 2_usize, _4); -+ assert(move _5, "index out of bounds: the length is {} but the index is {}", move _4, const 2_usize) -> [success: bb1, unwind continue]; ++ _4 = const 5000_usize; ++ _5 = const true; ++ assert(const true, "index out of bounds: the length is {} but the index is {}", const 5000_usize, const 2_usize) -> [success: bb1, unwind continue]; } bb1: { diff --git a/tests/mir-opt/const_prop/large_array_index.main.GVN.64bit.panic-abort.diff b/tests/mir-opt/const_prop/large_array_index.main.GVN.64bit.panic-abort.diff index cf36109fdcb..bd987c01ab1 100644 --- a/tests/mir-opt/const_prop/large_array_index.main.GVN.64bit.panic-abort.diff +++ b/tests/mir-opt/const_prop/large_array_index.main.GVN.64bit.panic-abort.diff @@ -18,11 +18,12 @@ _2 = [const 0_u8; 5000]; StorageLive(_3); _3 = const 2_usize; - _4 = Len(_2); +- _4 = Len(_2); - _5 = Lt(_3, _4); - assert(move _5, "index out of bounds: the length is {} but the index is {}", move _4, _3) -> [success: bb1, unwind unreachable]; -+ _5 = Lt(const 2_usize, _4); -+ assert(move _5, "index out of bounds: the length is {} but the index is {}", move _4, const 2_usize) -> [success: bb1, unwind unreachable]; ++ _4 = const 5000_usize; ++ _5 = const true; ++ assert(const true, "index out of bounds: the length is {} but the index is {}", const 5000_usize, const 2_usize) -> [success: bb1, unwind unreachable]; } bb1: { diff --git a/tests/mir-opt/const_prop/large_array_index.main.GVN.64bit.panic-unwind.diff b/tests/mir-opt/const_prop/large_array_index.main.GVN.64bit.panic-unwind.diff index 40ed9697180..e9ebef84ae0 100644 --- a/tests/mir-opt/const_prop/large_array_index.main.GVN.64bit.panic-unwind.diff +++ b/tests/mir-opt/const_prop/large_array_index.main.GVN.64bit.panic-unwind.diff @@ -18,11 +18,12 @@ _2 = [const 0_u8; 5000]; StorageLive(_3); _3 = const 2_usize; - _4 = Len(_2); +- _4 = Len(_2); - _5 = Lt(_3, _4); - assert(move _5, "index out of bounds: the length is {} but the index is {}", move _4, _3) -> [success: bb1, unwind continue]; -+ _5 = Lt(const 2_usize, _4); -+ assert(move _5, "index out of bounds: the length is {} but the index is {}", move _4, const 2_usize) -> [success: bb1, unwind continue]; ++ _4 = const 5000_usize; ++ _5 = const true; ++ assert(const true, "index out of bounds: the length is {} but the index is {}", const 5000_usize, const 2_usize) -> [success: bb1, unwind continue]; } bb1: { diff --git a/tests/mir-opt/const_prop/repeat.main.GVN.32bit.panic-abort.diff b/tests/mir-opt/const_prop/repeat.main.GVN.32bit.panic-abort.diff index a52e6e35483..71635b8e9c3 100644 --- a/tests/mir-opt/const_prop/repeat.main.GVN.32bit.panic-abort.diff +++ b/tests/mir-opt/const_prop/repeat.main.GVN.32bit.panic-abort.diff @@ -20,11 +20,12 @@ _3 = [const 42_u32; 8]; StorageLive(_4); _4 = const 2_usize; - _5 = Len(_3); +- _5 = Len(_3); - _6 = Lt(_4, _5); - assert(move _6, "index out of bounds: the length is {} but the index is {}", move _5, _4) -> [success: bb1, unwind unreachable]; -+ _6 = Lt(const 2_usize, _5); -+ assert(move _6, "index out of bounds: the length is {} but the index is {}", move _5, const 2_usize) -> [success: bb1, unwind unreachable]; ++ _5 = const 8_usize; ++ _6 = const true; ++ assert(const true, "index out of bounds: the length is {} but the index is {}", const 8_usize, const 2_usize) -> [success: bb1, unwind unreachable]; } bb1: { diff --git a/tests/mir-opt/const_prop/repeat.main.GVN.32bit.panic-unwind.diff b/tests/mir-opt/const_prop/repeat.main.GVN.32bit.panic-unwind.diff index fe0acee71eb..84205028d6d 100644 --- a/tests/mir-opt/const_prop/repeat.main.GVN.32bit.panic-unwind.diff +++ b/tests/mir-opt/const_prop/repeat.main.GVN.32bit.panic-unwind.diff @@ -20,11 +20,12 @@ _3 = [const 42_u32; 8]; StorageLive(_4); _4 = const 2_usize; - _5 = Len(_3); +- _5 = Len(_3); - _6 = Lt(_4, _5); - assert(move _6, "index out of bounds: the length is {} but the index is {}", move _5, _4) -> [success: bb1, unwind continue]; -+ _6 = Lt(const 2_usize, _5); -+ assert(move _6, "index out of bounds: the length is {} but the index is {}", move _5, const 2_usize) -> [success: bb1, unwind continue]; ++ _5 = const 8_usize; ++ _6 = const true; ++ assert(const true, "index out of bounds: the length is {} but the index is {}", const 8_usize, const 2_usize) -> [success: bb1, unwind continue]; } bb1: { diff --git a/tests/mir-opt/const_prop/repeat.main.GVN.64bit.panic-abort.diff b/tests/mir-opt/const_prop/repeat.main.GVN.64bit.panic-abort.diff index a52e6e35483..71635b8e9c3 100644 --- a/tests/mir-opt/const_prop/repeat.main.GVN.64bit.panic-abort.diff +++ b/tests/mir-opt/const_prop/repeat.main.GVN.64bit.panic-abort.diff @@ -20,11 +20,12 @@ _3 = [const 42_u32; 8]; StorageLive(_4); _4 = const 2_usize; - _5 = Len(_3); +- _5 = Len(_3); - _6 = Lt(_4, _5); - assert(move _6, "index out of bounds: the length is {} but the index is {}", move _5, _4) -> [success: bb1, unwind unreachable]; -+ _6 = Lt(const 2_usize, _5); -+ assert(move _6, "index out of bounds: the length is {} but the index is {}", move _5, const 2_usize) -> [success: bb1, unwind unreachable]; ++ _5 = const 8_usize; ++ _6 = const true; ++ assert(const true, "index out of bounds: the length is {} but the index is {}", const 8_usize, const 2_usize) -> [success: bb1, unwind unreachable]; } bb1: { diff --git a/tests/mir-opt/const_prop/repeat.main.GVN.64bit.panic-unwind.diff b/tests/mir-opt/const_prop/repeat.main.GVN.64bit.panic-unwind.diff index fe0acee71eb..84205028d6d 100644 --- a/tests/mir-opt/const_prop/repeat.main.GVN.64bit.panic-unwind.diff +++ b/tests/mir-opt/const_prop/repeat.main.GVN.64bit.panic-unwind.diff @@ -20,11 +20,12 @@ _3 = [const 42_u32; 8]; StorageLive(_4); _4 = const 2_usize; - _5 = Len(_3); +- _5 = Len(_3); - _6 = Lt(_4, _5); - assert(move _6, "index out of bounds: the length is {} but the index is {}", move _5, _4) -> [success: bb1, unwind continue]; -+ _6 = Lt(const 2_usize, _5); -+ assert(move _6, "index out of bounds: the length is {} but the index is {}", move _5, const 2_usize) -> [success: bb1, unwind continue]; ++ _5 = const 8_usize; ++ _6 = const true; ++ assert(const true, "index out of bounds: the length is {} but the index is {}", const 8_usize, const 2_usize) -> [success: bb1, unwind continue]; } bb1: { diff --git a/tests/mir-opt/gvn.repeated_index.GVN.panic-abort.diff b/tests/mir-opt/gvn.repeated_index.GVN.panic-abort.diff index d937902e891..8ce05c9b340 100644 --- a/tests/mir-opt/gvn.repeated_index.GVN.panic-abort.diff +++ b/tests/mir-opt/gvn.repeated_index.GVN.panic-abort.diff @@ -32,11 +32,12 @@ StorageLive(_6); StorageLive(_7); _7 = const 0_usize; - _8 = Len(_3); +- _8 = Len(_3); - _9 = Lt(_7, _8); - assert(move _9, "index out of bounds: the length is {} but the index is {}", move _8, _7) -> [success: bb1, unwind unreachable]; -+ _9 = Lt(const 0_usize, _8); -+ assert(move _9, "index out of bounds: the length is {} but the index is {}", _8, const 0_usize) -> [success: bb1, unwind unreachable]; ++ _8 = const N; ++ _9 = Lt(const 0_usize, const N); ++ assert(move _9, "index out of bounds: the length is {} but the index is {}", const N, const 0_usize) -> [success: bb1, unwind unreachable]; } bb1: { @@ -57,9 +58,9 @@ - _13 = Len(_3); - _14 = Lt(_12, _13); - assert(move _14, "index out of bounds: the length is {} but the index is {}", move _13, _12) -> [success: bb3, unwind unreachable]; -+ _13 = _8; -+ _14 = Lt(_2, _8); -+ assert(move _14, "index out of bounds: the length is {} but the index is {}", _8, _2) -> [success: bb3, unwind unreachable]; ++ _13 = const N; ++ _14 = Lt(_2, const N); ++ assert(move _14, "index out of bounds: the length is {} but the index is {}", const N, _2) -> [success: bb3, unwind unreachable]; } bb3: { diff --git a/tests/mir-opt/gvn.repeated_index.GVN.panic-unwind.diff b/tests/mir-opt/gvn.repeated_index.GVN.panic-unwind.diff index dd4d24b12ea..7ed547eeb4a 100644 --- a/tests/mir-opt/gvn.repeated_index.GVN.panic-unwind.diff +++ b/tests/mir-opt/gvn.repeated_index.GVN.panic-unwind.diff @@ -32,11 +32,12 @@ StorageLive(_6); StorageLive(_7); _7 = const 0_usize; - _8 = Len(_3); +- _8 = Len(_3); - _9 = Lt(_7, _8); - assert(move _9, "index out of bounds: the length is {} but the index is {}", move _8, _7) -> [success: bb1, unwind continue]; -+ _9 = Lt(const 0_usize, _8); -+ assert(move _9, "index out of bounds: the length is {} but the index is {}", _8, const 0_usize) -> [success: bb1, unwind continue]; ++ _8 = const N; ++ _9 = Lt(const 0_usize, const N); ++ assert(move _9, "index out of bounds: the length is {} but the index is {}", const N, const 0_usize) -> [success: bb1, unwind continue]; } bb1: { @@ -57,9 +58,9 @@ - _13 = Len(_3); - _14 = Lt(_12, _13); - assert(move _14, "index out of bounds: the length is {} but the index is {}", move _13, _12) -> [success: bb3, unwind continue]; -+ _13 = _8; -+ _14 = Lt(_2, _8); -+ assert(move _14, "index out of bounds: the length is {} but the index is {}", _8, _2) -> [success: bb3, unwind continue]; ++ _13 = const N; ++ _14 = Lt(_2, const N); ++ assert(move _14, "index out of bounds: the length is {} but the index is {}", const N, _2) -> [success: bb3, unwind continue]; } bb3: { |