diff options
| -rw-r--r-- | compiler/rustc_codegen_cranelift/src/discriminant.rs | 89 | ||||
| -rw-r--r-- | compiler/rustc_codegen_ssa/src/mir/place.rs | 92 | ||||
| -rw-r--r-- | src/tools/tidy/src/ui_tests.rs | 2 | ||||
| -rw-r--r-- | tests/codegen/enum-match.rs | 7 | ||||
| -rw-r--r-- | tests/ui/enum-discriminant/issue-104519.rs | 10 | ||||
| -rw-r--r-- | tests/ui/enum-discriminant/issue-61696.rs (renamed from tests/ui/issues/issue-61696.rs) | 21 |
6 files changed, 22 insertions, 199 deletions
diff --git a/compiler/rustc_codegen_cranelift/src/discriminant.rs b/compiler/rustc_codegen_cranelift/src/discriminant.rs index f740945a03c..670384663e8 100644 --- a/compiler/rustc_codegen_cranelift/src/discriminant.rs +++ b/compiler/rustc_codegen_cranelift/src/discriminant.rs @@ -103,7 +103,6 @@ pub(crate) fn codegen_get_discriminant<'tcx>( } }; - let cast_to_size = dest_layout.layout.size(); let cast_to = fx.clif_type(dest_layout.ty).unwrap(); // Read the tag/niche-encoded discriminant from memory. @@ -122,21 +121,7 @@ pub(crate) fn codegen_get_discriminant<'tcx>( dest.write_cvalue(fx, res); } TagEncoding::Niche { untagged_variant, ref niche_variants, niche_start } => { - let tag_size = tag_scalar.size(fx); - let max_unsigned = tag_size.unsigned_int_max(); - let max_signed = tag_size.signed_int_max() as u128; - let min_signed = max_signed + 1; let relative_max = niche_variants.end().as_u32() - niche_variants.start().as_u32(); - let niche_end = niche_start.wrapping_add(relative_max as u128) & max_unsigned; - let range = tag_scalar.valid_range(fx); - - let sle = |lhs: u128, rhs: u128| -> bool { - // Signed and unsigned comparisons give the same results, - // except that in signed comparisons an integer with the - // sign bit set is less than one with the sign bit clear. - // Toggle the sign bit to do a signed comparison. - (lhs ^ min_signed) <= (rhs ^ min_signed) - }; // We have a subrange `niche_start..=niche_end` inside `range`. // If the value of the tag is inside this subrange, it's a @@ -153,45 +138,6 @@ pub(crate) fn codegen_get_discriminant<'tcx>( // } // However, we will likely be able to emit simpler code. - // Find the least and greatest values in `range`, considered - // both as signed and unsigned. - let (low_unsigned, high_unsigned) = - if range.start <= range.end { (range.start, range.end) } else { (0, max_unsigned) }; - let (low_signed, high_signed) = if sle(range.start, range.end) { - (range.start, range.end) - } else { - (min_signed, max_signed) - }; - - let niches_ule = niche_start <= niche_end; - let niches_sle = sle(niche_start, niche_end); - let cast_smaller = cast_to_size <= tag_size; - - // In the algorithm above, we can change - // cast(relative_tag) + niche_variants.start() - // into - // cast(tag + (niche_variants.start() - niche_start)) - // if either the casted type is no larger than the original - // type, or if the niche values are contiguous (in either the - // signed or unsigned sense). - let can_incr = cast_smaller || niches_ule || niches_sle; - - let data_for_boundary_niche = || -> Option<(IntCC, u128)> { - if !can_incr { - None - } else if niche_start == low_unsigned { - Some((IntCC::UnsignedLessThanOrEqual, niche_end)) - } else if niche_end == high_unsigned { - Some((IntCC::UnsignedGreaterThanOrEqual, niche_start)) - } else if niche_start == low_signed { - Some((IntCC::SignedLessThanOrEqual, niche_end)) - } else if niche_end == high_signed { - Some((IntCC::SignedGreaterThanOrEqual, niche_start)) - } else { - None - } - }; - let (is_niche, tagged_discr, delta) = if relative_max == 0 { // Best case scenario: only one tagged variant. This will // likely become just a comparison and a jump. @@ -206,41 +152,6 @@ pub(crate) fn codegen_get_discriminant<'tcx>( let tagged_discr = fx.bcx.ins().iconst(cast_to, niche_variants.start().as_u32() as i64); (is_niche, tagged_discr, 0) - } else if let Some((predicate, constant)) = data_for_boundary_niche() { - // The niche values are either the lowest or the highest in - // `range`. We can avoid the first subtraction in the - // algorithm. - // The algorithm is now this: - // is_niche = tag <= niche_end - // discr = if is_niche { - // cast(tag + (niche_variants.start() - niche_start)) - // } else { - // untagged_variant - // } - // (the first line may instead be tag >= niche_start, - // and may be a signed or unsigned comparison) - // The arithmetic must be done before the cast, so we can - // have the correct wrapping behavior. See issue #104519 for - // the consequences of getting this wrong. - let is_niche = codegen_icmp_imm(fx, predicate, tag, constant as i128); - let delta = (niche_variants.start().as_u32() as u128).wrapping_sub(niche_start); - let incr_tag = if delta == 0 { - tag - } else { - let delta = match fx.bcx.func.dfg.value_type(tag) { - types::I128 => { - let lsb = fx.bcx.ins().iconst(types::I64, delta as u64 as i64); - let msb = fx.bcx.ins().iconst(types::I64, (delta >> 64) as u64 as i64); - fx.bcx.ins().iconcat(lsb, msb) - } - ty => fx.bcx.ins().iconst(ty, delta as i64), - }; - fx.bcx.ins().iadd(tag, delta) - }; - - let cast_tag = clif_intcast(fx, incr_tag, cast_to, !niches_ule); - - (is_niche, cast_tag, 0) } else { // The special cases don't apply, so we'll have to go with // the general algorithm. diff --git a/compiler/rustc_codegen_ssa/src/mir/place.rs b/compiler/rustc_codegen_ssa/src/mir/place.rs index 1633cfef19d..a58a61cd567 100644 --- a/compiler/rustc_codegen_ssa/src/mir/place.rs +++ b/compiler/rustc_codegen_ssa/src/mir/place.rs @@ -211,7 +211,6 @@ impl<'a, 'tcx, V: CodegenObject> PlaceRef<'tcx, V> { ) -> V { let dl = &bx.tcx().data_layout; let cast_to_layout = bx.cx().layout_of(cast_to); - let cast_to_size = cast_to_layout.layout.size(); let cast_to = bx.cx().immediate_backend_type(cast_to_layout); if self.layout.abi.is_uninhabited() { return bx.cx().const_poison(cast_to); @@ -261,21 +260,7 @@ impl<'a, 'tcx, V: CodegenObject> PlaceRef<'tcx, V> { _ => (tag_imm, bx.cx().immediate_backend_type(tag_op.layout)), }; - let tag_size = tag_scalar.size(bx.cx()); - let max_unsigned = tag_size.unsigned_int_max(); - let max_signed = tag_size.signed_int_max() as u128; - let min_signed = max_signed + 1; let relative_max = niche_variants.end().as_u32() - niche_variants.start().as_u32(); - let niche_end = niche_start.wrapping_add(relative_max as u128) & max_unsigned; - let range = tag_scalar.valid_range(bx.cx()); - - let sle = |lhs: u128, rhs: u128| -> bool { - // Signed and unsigned comparisons give the same results, - // except that in signed comparisons an integer with the - // sign bit set is less than one with the sign bit clear. - // Toggle the sign bit to do a signed comparison. - (lhs ^ min_signed) <= (rhs ^ min_signed) - }; // We have a subrange `niche_start..=niche_end` inside `range`. // If the value of the tag is inside this subrange, it's a @@ -291,49 +276,6 @@ impl<'a, 'tcx, V: CodegenObject> PlaceRef<'tcx, V> { // untagged_variant // } // However, we will likely be able to emit simpler code. - - // Find the least and greatest values in `range`, considered - // both as signed and unsigned. - let (low_unsigned, high_unsigned) = if range.start <= range.end { - (range.start, range.end) - } else { - (0, max_unsigned) - }; - let (low_signed, high_signed) = if sle(range.start, range.end) { - (range.start, range.end) - } else { - (min_signed, max_signed) - }; - - let niches_ule = niche_start <= niche_end; - let niches_sle = sle(niche_start, niche_end); - let cast_smaller = cast_to_size <= tag_size; - - // In the algorithm above, we can change - // cast(relative_tag) + niche_variants.start() - // into - // cast(tag + (niche_variants.start() - niche_start)) - // if either the casted type is no larger than the original - // type, or if the niche values are contiguous (in either the - // signed or unsigned sense). - let can_incr = cast_smaller || niches_ule || niches_sle; - - let data_for_boundary_niche = || -> Option<(IntPredicate, u128)> { - if !can_incr { - None - } else if niche_start == low_unsigned { - Some((IntPredicate::IntULE, niche_end)) - } else if niche_end == high_unsigned { - Some((IntPredicate::IntUGE, niche_start)) - } else if niche_start == low_signed { - Some((IntPredicate::IntSLE, niche_end)) - } else if niche_end == high_signed { - Some((IntPredicate::IntSGE, niche_start)) - } else { - None - } - }; - let (is_niche, tagged_discr, delta) = if relative_max == 0 { // Best case scenario: only one tagged variant. This will // likely become just a comparison and a jump. @@ -349,40 +291,6 @@ impl<'a, 'tcx, V: CodegenObject> PlaceRef<'tcx, V> { let tagged_discr = bx.cx().const_uint(cast_to, niche_variants.start().as_u32() as u64); (is_niche, tagged_discr, 0) - } else if let Some((predicate, constant)) = data_for_boundary_niche() { - // The niche values are either the lowest or the highest in - // `range`. We can avoid the first subtraction in the - // algorithm. - // The algorithm is now this: - // is_niche = tag <= niche_end - // discr = if is_niche { - // cast(tag + (niche_variants.start() - niche_start)) - // } else { - // untagged_variant - // } - // (the first line may instead be tag >= niche_start, - // and may be a signed or unsigned comparison) - // The arithmetic must be done before the cast, so we can - // have the correct wrapping behavior. See issue #104519 for - // the consequences of getting this wrong. - let is_niche = - bx.icmp(predicate, tag, bx.cx().const_uint_big(tag_llty, constant)); - let delta = (niche_variants.start().as_u32() as u128).wrapping_sub(niche_start); - let incr_tag = if delta == 0 { - tag - } else { - bx.add(tag, bx.cx().const_uint_big(tag_llty, delta)) - }; - - let cast_tag = if cast_smaller { - bx.intcast(incr_tag, cast_to, false) - } else if niches_ule { - bx.zext(incr_tag, cast_to) - } else { - bx.sext(incr_tag, cast_to) - }; - - (is_niche, cast_tag, 0) } else { // The special cases don't apply, so we'll have to go with // the general algorithm. diff --git a/src/tools/tidy/src/ui_tests.rs b/src/tools/tidy/src/ui_tests.rs index 3d7f9828a7e..29664c854c8 100644 --- a/src/tools/tidy/src/ui_tests.rs +++ b/src/tools/tidy/src/ui_tests.rs @@ -10,7 +10,7 @@ use std::path::{Path, PathBuf}; // FIXME: The following limits should be reduced eventually. const ENTRY_LIMIT: usize = 885; const ROOT_ENTRY_LIMIT: usize = 891; -const ISSUES_ENTRY_LIMIT: usize = 1978; +const ISSUES_ENTRY_LIMIT: usize = 1977; fn check_entries(tests_path: &Path, bad: &mut bool) { let mut directories: HashMap<PathBuf, usize> = HashMap::new(); diff --git a/tests/codegen/enum-match.rs b/tests/codegen/enum-match.rs index 5f8063a27f7..36c6be19012 100644 --- a/tests/codegen/enum-match.rs +++ b/tests/codegen/enum-match.rs @@ -34,8 +34,11 @@ pub enum Enum1 { // CHECK: define noundef i8 @match1{{.*}} // CHECK-NEXT: start: -// CHECK-NEXT: [[DISCR:%.*]] = {{.*}}call i8 @llvm.usub.sat.i8(i8 %0, i8 1) -// CHECK-NEXT: switch i8 [[DISCR]], label {{.*}} [ +// CHECK-NEXT: %1 = add i8 %0, -2 +// CHECK-NEXT: %2 = zext i8 %1 to i64 +// CHECK-NEXT: %3 = icmp ult i8 %1, 2 +// CHECK-NEXT: %4 = add nuw nsw i64 %2, 1 +// CHECK-NEXT: %_2 = select i1 %3, i64 %4, i64 0 #[no_mangle] pub fn match1(e: Enum1) -> u8 { use Enum1::*; diff --git a/tests/ui/enum-discriminant/issue-104519.rs b/tests/ui/enum-discriminant/issue-104519.rs index c4630f76b3a..507c0988fcc 100644 --- a/tests/ui/enum-discriminant/issue-104519.rs +++ b/tests/ui/enum-discriminant/issue-104519.rs @@ -23,14 +23,4 @@ fn some_match(result: OpenResult) -> u8 { fn main() { let result = OpenResult::Ok(()); assert_eq!(some_match(result), 0); - - let result = OpenResult::Ok(()); - match result { - OpenResult::Ok(()) => (), - _ => unreachable!("message a"), - } - match result { - OpenResult::Ok(()) => (), - _ => unreachable!("message b"), - } } diff --git a/tests/ui/issues/issue-61696.rs b/tests/ui/enum-discriminant/issue-61696.rs index dca52927fd7..8a633a916c8 100644 --- a/tests/ui/issues/issue-61696.rs +++ b/tests/ui/enum-discriminant/issue-61696.rs @@ -55,12 +55,23 @@ pub enum E2<X> { V4, } -fn main() { - if let E1::V2 { .. } = (E1::V1 { f: true }) { - unreachable!() +#[inline(never)] +fn match_e1(y: E1) -> u8 { + match y { + E1::V2 { .. } => 1, + _ => 0, } +} - if let E2::V1 { .. } = E2::V3::<Infallible> { - unreachable!() +#[inline(never)] +fn match_e2(y: E2<Infallible>) -> u8 { + match y { + E2::V1 { .. } => 1, + _ => 0, } } + +fn main() { + assert_eq!(match_e1(E1::V1 { f: true }), 0); + assert_eq!(match_e2(E2::V3), 0); +} |