tests/codegen-llvm/enum/enum-match.rs

//@ compile-flags: -Copt-level=1
//@ only-64bit

#![crate_type = "lib"]
#![feature(core_intrinsics)]

// Check each of the 3 cases for `codegen_get_discr`.

// FIXME: once our min-bar LLVM has `range` attributes, update the various
// tests here to no longer have the `range`s and `nsw`s as optional.

// Case 0: One tagged variant.
pub enum Enum0 {
    A(bool),
    B,
}

// CHECK-LABEL: define{{( dso_local)?}} noundef{{( range\(i8 [0-9]+, [0-9]+\))?}} i8 @match0(i8{{.+}}%0)
// CHECK-NEXT: start:
// CHECK-NEXT: %[[IS_B:.+]] = icmp eq i8 %0, 2
// CHECK-NEXT: %[[TRUNC:.+]] = and i8 %0, 1
// CHECK-NEXT: %[[R:.+]] = select i1 %[[IS_B]], i8 13, i8 %[[TRUNC]]
// CHECK-NEXT: ret i8 %[[R]]
#[no_mangle]
pub fn match0(e: Enum0) -> u8 {
    use Enum0::*;
    match e {
        A(b) => b as u8,
        B => 13,
    }
}

// Case 1: Niche values are on a boundary for `range`.
pub enum Enum1 {
    A(bool),
    B,
    C,
}

// CHECK-LABEL: define{{( dso_local)?}} noundef{{( range\(i8 [0-9]+, [0-9]+\))?}} i8 @match1(i8{{.+}}%0)
// CHECK-NEXT: start:
// CHECK-NEXT: %[[REL_VAR:.+]] = add{{( nsw)?}} i8 %0, -2
// CHECK-NEXT: %[[REL_VAR_WIDE:.+]] = zext i8 %[[REL_VAR]] to i64
// CHECK-NEXT: %[[IS_NICHE:.+]] = icmp{{( samesign)?}} ugt i8 %0, 1
// CHECK-NEXT: %[[NICHE_DISCR:.+]] = add nuw nsw i64 %[[REL_VAR_WIDE]], 1
// CHECK-NEXT: %[[DISCR:.+]] = select i1 %[[IS_NICHE]], i64 %[[NICHE_DISCR]], i64 0
// CHECK-NEXT: switch i64 %[[DISCR]]
#[no_mangle]
pub fn match1(e: Enum1) -> u8 {
    use Enum1::*;
    match e {
        A(b) => b as u8,
        B => 13,
        C => 100,
    }
}

// Case 2: Special cases don't apply.
#[rustfmt::skip]
pub enum X {
    _2=2, _3, _4, _5, _6, _7, _8, _9, _10, _11,
    _12, _13, _14, _15, _16, _17, _18, _19, _20,
    _21, _22, _23, _24, _25, _26, _27, _28, _29,
    _30, _31, _32, _33, _34, _35, _36, _37, _38,
    _39, _40, _41, _42, _43, _44, _45, _46, _47,
    _48, _49, _50, _51, _52, _53, _54, _55, _56,
    _57, _58, _59, _60, _61, _62, _63, _64, _65,
    _66, _67, _68, _69, _70, _71, _72, _73, _74,
    _75, _76, _77, _78, _79, _80, _81, _82, _83,
    _84, _85, _86, _87, _88, _89, _90, _91, _92,
    _93, _94, _95, _96, _97, _98, _99, _100, _101,
    _102, _103, _104, _105, _106, _107, _108, _109,
    _110, _111, _112, _113, _114, _115, _116, _117,
    _118, _119, _120, _121, _122, _123, _124, _125,
    _126, _127, _128, _129, _130, _131, _132, _133,
    _134, _135, _136, _137, _138, _139, _140, _141,
    _142, _143, _144, _145, _146, _147, _148, _149,
    _150, _151, _152, _153, _154, _155, _156, _157,
    _158, _159, _160, _161, _162, _163, _164, _165,
    _166, _167, _168, _169, _170, _171, _172, _173,
    _174, _175, _176, _177, _178, _179, _180, _181,
    _182, _183, _184, _185, _186, _187, _188, _189,
    _190, _191, _192, _193, _194, _195, _196, _197,
    _198, _199, _200, _201, _202, _203, _204, _205,
    _206, _207, _208, _209, _210, _211, _212, _213,
    _214, _215, _216, _217, _218, _219, _220, _221,
    _222, _223, _224, _225, _226, _227, _228, _229,
    _230, _231, _232, _233, _234, _235, _236, _237,
    _238, _239, _240, _241, _242, _243, _244, _245,
    _246, _247, _248, _249, _250, _251, _252, _253,
}

pub enum Enum2 {
    A(X),
    B,
    C,
    D,
    E,
}

// CHECK-LABEL: define{{( dso_local)?}} noundef{{( range\(i8 [0-9]+, -?[0-9]+\))?}} i8 @match2(i8{{.+}}%0)
// CHECK-NEXT: start:
// CHECK-NEXT: %[[REL_VAR:.+]] = add i8 %0, 2
// CHECK-NEXT: %[[REL_VAR_WIDE:.+]] = zext i8 %[[REL_VAR]] to i64
// CHECK-NEXT: %[[IS_NICHE:.+]] = icmp ult i8 %[[REL_VAR]], 4
// CHECK-NEXT: %[[NICHE_DISCR:.+]] = add nuw nsw i64 %[[REL_VAR_WIDE]], 1
// CHECK-NEXT: %[[DISCR:.+]] = select i1 %[[IS_NICHE]], i64 %[[NICHE_DISCR]], i64 0
// CHECK-NEXT: switch i64 %[[DISCR]]
#[no_mangle]
pub fn match2(e: Enum2) -> u8 {
    use Enum2::*;
    match e {
        A(b) => b as u8,
        B => 13,
        C => 100,
        D => 200,
        E => 250,
    }
}

// And make sure it works even if the niched scalar is a pointer.
// (For example, that we don't try to `sub` on pointers.)

// CHECK-LABEL: define{{( dso_local)?}} noundef{{( range\(i16 -?[0-9]+, -?[0-9]+\))?}} i16 @match3(ptr{{.+}}%0)
// CHECK-NEXT: start:
// CHECK-NEXT: %[[IS_NULL:.+]] = icmp eq ptr %0, null
// CHECK-NEXT: br i1 %[[IS_NULL]]
#[no_mangle]
pub fn match3(e: Option<&u8>) -> i16 {
    match e {
        Some(r) => *r as _,
        None => -1,
    }
}

// If the untagged variant is in the middle, there's an impossible value that's
// not reflected in the `range` parameter attribute, so we assume it away.

#[derive(PartialEq)]
pub enum MiddleNiche {
    A,       // tag 2
    B,       // tag 3
    C(bool), // untagged
    D,       // tag 5
    E,       // tag 6
}

// CHECK-LABEL: define{{( dso_local)?}} noundef{{( range\(i8 -?[0-9]+, -?[0-9]+\))?}} i8 @match4(i8{{.+}}%0)
// CHECK-NEXT: start:
// CHECK-NEXT: %[[NOT_IMPOSSIBLE:.+]] = icmp ne i8 %0, 4
// CHECK-NEXT: call void @llvm.assume(i1 %[[NOT_IMPOSSIBLE]])
// CHECK-NEXT: %[[REL_VAR:.+]] = add{{( nsw)?}} i8 %0, -2
// CHECK-NEXT: %[[NOT_NICHE:.+]] = icmp{{( samesign)?}} ult i8 %0, 2
// CHECK-NEXT: %[[DISCR:.+]] = select i1 %[[NOT_NICHE]], i8 2, i8 %[[REL_VAR]]
// CHECK-NEXT: switch i8 %[[DISCR]]
#[no_mangle]
pub fn match4(e: MiddleNiche) -> u8 {
    use MiddleNiche::*;
    match e {
        A => 13,
        B => 100,
        C(b) => b as u8,
        D => 200,
        E => 250,
    }
}

// CHECK-LABEL: define{{.+}}i1 @match4_is_c(i8{{.+}}%e)
// CHECK-NEXT: start
// CHECK-NEXT: %[[NOT_IMPOSSIBLE:.+]] = icmp ne i8 %e, 4
// CHECK-NEXT: call void @llvm.assume(i1 %[[NOT_IMPOSSIBLE]])
// CHECK-NEXT: %[[IS_C:.+]] = icmp{{( samesign)?}} ult i8 %e, 2
// CHECK-NEXT: ret i1 %[[IS_C]]
#[no_mangle]
pub fn match4_is_c(e: MiddleNiche) -> bool {
    // Before #139098, this couldn't optimize out the `select` because it looked
    // like it was possible for a `2` to be produced on both sides.

    std::intrinsics::discriminant_value(&e) == 2
}

// You have to do something pretty obnoxious to get a variant index that doesn't
// fit in the tag size, but it's possible

pub enum Never {}

pub enum HugeVariantIndex {
    V000(Never),
    V001(Never),
    V002(Never),
    V003(Never),
    V004(Never),
    V005(Never),
    V006(Never),
    V007(Never),
    V008(Never),
    V009(Never),
    V010(Never),
    V011(Never),
    V012(Never),
    V013(Never),
    V014(Never),
    V015(Never),
    V016(Never),
    V017(Never),
    V018(Never),
    V019(Never),
    V020(Never),
    V021(Never),
    V022(Never),
    V023(Never),
    V024(Never),
    V025(Never),
    V026(Never),
    V027(Never),
    V028(Never),
    V029(Never),
    V030(Never),
    V031(Never),
    V032(Never),
    V033(Never),
    V034(Never),
    V035(Never),
    V036(Never),
    V037(Never),
    V038(Never),
    V039(Never),
    V040(Never),
    V041(Never),
    V042(Never),
    V043(Never),
    V044(Never),
    V045(Never),
    V046(Never),
    V047(Never),
    V048(Never),
    V049(Never),
    V050(Never),
    V051(Never),
    V052(Never),
    V053(Never),
    V054(Never),
    V055(Never),
    V056(Never),
    V057(Never),
    V058(Never),
    V059(Never),
    V060(Never),
    V061(Never),
    V062(Never),
    V063(Never),
    V064(Never),
    V065(Never),
    V066(Never),
    V067(Never),
    V068(Never),
    V069(Never),
    V070(Never),
    V071(Never),
    V072(Never),
    V073(Never),
    V074(Never),
    V075(Never),
    V076(Never),
    V077(Never),
    V078(Never),
    V079(Never),
    V080(Never),
    V081(Never),
    V082(Never),
    V083(Never),
    V084(Never),
    V085(Never),
    V086(Never),
    V087(Never),
    V088(Never),
    V089(Never),
    V090(Never),
    V091(Never),
    V092(Never),
    V093(Never),
    V094(Never),
    V095(Never),
    V096(Never),
    V097(Never),
    V098(Never),
    V099(Never),
    V100(Never),
    V101(Never),
    V102(Never),
    V103(Never),
    V104(Never),
    V105(Never),
    V106(Never),
    V107(Never),
    V108(Never),
    V109(Never),
    V110(Never),
    V111(Never),
    V112(Never),
    V113(Never),
    V114(Never),
    V115(Never),
    V116(Never),
    V117(Never),
    V118(Never),
    V119(Never),
    V120(Never),
    V121(Never),
    V122(Never),
    V123(Never),
    V124(Never),
    V125(Never),
    V126(Never),
    V127(Never),
    V128(Never),
    V129(Never),
    V130(Never),
    V131(Never),
    V132(Never),
    V133(Never),
    V134(Never),
    V135(Never),
    V136(Never),
    V137(Never),
    V138(Never),
    V139(Never),
    V140(Never),
    V141(Never),
    V142(Never),
    V143(Never),
    V144(Never),
    V145(Never),
    V146(Never),
    V147(Never),
    V148(Never),
    V149(Never),
    V150(Never),
    V151(Never),
    V152(Never),
    V153(Never),
    V154(Never),
    V155(Never),
    V156(Never),
    V157(Never),
    V158(Never),
    V159(Never),
    V160(Never),
    V161(Never),
    V162(Never),
    V163(Never),
    V164(Never),
    V165(Never),
    V166(Never),
    V167(Never),
    V168(Never),
    V169(Never),
    V170(Never),
    V171(Never),
    V172(Never),
    V173(Never),
    V174(Never),
    V175(Never),
    V176(Never),
    V177(Never),
    V178(Never),
    V179(Never),
    V180(Never),
    V181(Never),
    V182(Never),
    V183(Never),
    V184(Never),
    V185(Never),
    V186(Never),
    V187(Never),
    V188(Never),
    V189(Never),
    V190(Never),
    V191(Never),
    V192(Never),
    V193(Never),
    V194(Never),
    V195(Never),
    V196(Never),
    V197(Never),
    V198(Never),
    V199(Never),
    V200(Never),
    V201(Never),
    V202(Never),
    V203(Never),
    V204(Never),
    V205(Never),
    V206(Never),
    V207(Never),
    V208(Never),
    V209(Never),
    V210(Never),
    V211(Never),
    V212(Never),
    V213(Never),
    V214(Never),
    V215(Never),
    V216(Never),
    V217(Never),
    V218(Never),
    V219(Never),
    V220(Never),
    V221(Never),
    V222(Never),
    V223(Never),
    V224(Never),
    V225(Never),
    V226(Never),
    V227(Never),
    V228(Never),
    V229(Never),
    V230(Never),
    V231(Never),
    V232(Never),
    V233(Never),
    V234(Never),
    V235(Never),
    V236(Never),
    V237(Never),
    V238(Never),
    V239(Never),
    V240(Never),
    V241(Never),
    V242(Never),
    V243(Never),
    V244(Never),
    V245(Never),
    V246(Never),
    V247(Never),
    V248(Never),
    V249(Never),
    V250(Never),
    V251(Never),
    V252(Never),
    V253(Never),
    V254(Never),
    V255(Never),
    V256(Never),

    Possible257,   // tag 2
    Bool258(bool), // untagged
    Possible259,   // tag 4
}

// CHECK-LABEL: define{{( dso_local)?}} noundef{{( range\(i8 [0-9]+, [0-9]+\))?}} i8 @match5(i8{{.+}}%0)
// CHECK-NEXT: start:
// CHECK-NEXT: %[[NOT_IMPOSSIBLE:.+]] = icmp ne i8 %0, 3
// CHECK-NEXT: call void @llvm.assume(i1 %[[NOT_IMPOSSIBLE]])
// CHECK-NEXT: %[[REL_VAR:.+]] = add{{( nsw)?}} i8 %0, -2
// CHECK-NEXT: %[[REL_VAR_WIDE:.+]] = zext i8 %[[REL_VAR]] to i64
// CHECK-NEXT: %[[IS_NICHE:.+]] = icmp{{( samesign)?}} ugt i8 %0, 1
// CHECK-NEXT: %[[NICHE_DISCR:.+]] = add nuw nsw i64 %[[REL_VAR_WIDE]], 257
// CHECK-NEXT: %[[DISCR:.+]] = select i1 %[[IS_NICHE]], i64 %[[NICHE_DISCR]], i64 258
// CHECK-NEXT: switch i64 %[[DISCR]],
// CHECK-NEXT:   i64 257,
// CHECK-NEXT:   i64 258,
// CHECK-NEXT:   i64 259,
#[no_mangle]
pub fn match5(e: HugeVariantIndex) -> u8 {
    use HugeVariantIndex::*;
    match e {
        Possible257 => 13,
        Bool258(b) => b as u8,
        Possible259 => 100,
    }
}

// Make an enum where the niche tags wrap both as signed and as unsigned, to hit
// the most-fallback case where there's just nothing smart to do.

pub enum E10Through65 {
    D10 = 10,
    D11 = 11,
    D12 = 12,
    D13 = 13,
    D14 = 14,
    D15 = 15,
    D16 = 16,
    D17 = 17,
    D18 = 18,
    D19 = 19,
    D20 = 20,
    D21 = 21,
    D22 = 22,
    D23 = 23,
    D24 = 24,
    D25 = 25,
    D26 = 26,
    D27 = 27,
    D28 = 28,
    D29 = 29,
    D30 = 30,
    D31 = 31,
    D32 = 32,
    D33 = 33,
    D34 = 34,
    D35 = 35,
    D36 = 36,
    D37 = 37,
    D38 = 38,
    D39 = 39,
    D40 = 40,
    D41 = 41,
    D42 = 42,
    D43 = 43,
    D44 = 44,
    D45 = 45,
    D46 = 46,
    D47 = 47,
    D48 = 48,
    D49 = 49,
    D50 = 50,
    D51 = 51,
    D52 = 52,
    D53 = 53,
    D54 = 54,
    D55 = 55,
    D56 = 56,
    D57 = 57,
    D58 = 58,
    D59 = 59,
    D60 = 60,
    D61 = 61,
    D62 = 62,
    D63 = 63,
    D64 = 64,
    D65 = 65,
}

pub enum Tricky {
    Untagged(E10Through65),
    V001,
    V002,
    V003,
    V004,
    V005,
    V006,
    V007,
    V008,
    V009,
    V010,
    V011,
    V012,
    V013,
    V014,
    V015,
    V016,
    V017,
    V018,
    V019,
    V020,
    V021,
    V022,
    V023,
    V024,
    V025,
    V026,
    V027,
    V028,
    V029,
    V030,
    V031,
    V032,
    V033,
    V034,
    V035,
    V036,
    V037,
    V038,
    V039,
    V040,
    V041,
    V042,
    V043,
    V044,
    V045,
    V046,
    V047,
    V048,
    V049,
    V050,
    V051,
    V052,
    V053,
    V054,
    V055,
    V056,
    V057,
    V058,
    V059,
    V060,
    V061,
    V062,
    V063,
    V064,
    V065,
    V066,
    V067,
    V068,
    V069,
    V070,
    V071,
    V072,
    V073,
    V074,
    V075,
    V076,
    V077,
    V078,
    V079,
    V080,
    V081,
    V082,
    V083,
    V084,
    V085,
    V086,
    V087,
    V088,
    V089,
    V090,
    V091,
    V092,
    V093,
    V094,
    V095,
    V096,
    V097,
    V098,
    V099,
    V100,
    V101,
    V102,
    V103,
    V104,
    V105,
    V106,
    V107,
    V108,
    V109,
    V110,
    V111,
    V112,
    V113,
    V114,
    V115,
    V116,
    V117,
    V118,
    V119,
    V120,
    V121,
    V122,
    V123,
    V124,
    V125,
    V126,
    V127,
    V128,
    V129,
    V130,
    V131,
    V132,
    V133,
    V134,
    V135,
    V136,
    V137,
    V138,
    V139,
    V140,
    V141,
    V142,
    V143,
    V144,
    V145,
    V146,
    V147,
    V148,
    V149,
    V150,
    V151,
    V152,
    V153,
    V154,
    V155,
    V156,
    V157,
    V158,
    V159,
    V160,
    V161,
    V162,
    V163,
    V164,
    V165,
    V166,
    V167,
    V168,
    V169,
    V170,
    V171,
    V172,
    V173,
    V174,
    V175,
    V176,
    V177,
    V178,
    V179,
    V180,
    V181,
    V182,
    V183,
    V184,
    V185,
    V186,
    V187,
    V188,
    V189,
    V190,
    V191,
    V192,
    V193,
    V194,
    V195,
    V196,
    V197,
    V198,
    V199,
    V200,
}

const _: () = assert!(std::intrinsics::discriminant_value(&Tricky::V100) == 100);

// CHECK-LABEL: define noundef{{( range\(i8 [0-9]+, [0-9]+\))?}} i8 @discriminant6(i8 noundef %e)
// CHECK-NEXT: start:
// CHECK-NEXT: %[[REL_VAR:.+]] = add i8 %e, -66
// CHECK-NEXT: %[[IS_NICHE:.+]] = icmp ult i8 %[[REL_VAR]], -56
// CHECK-NEXT: %[[TAGGED_DISCR:.+]] = add i8 %e, -65
// CHECK-NEXT: %[[DISCR:.+]] = select i1 %[[IS_NICHE]], i8 %[[TAGGED_DISCR]], i8 0
// CHECK-NEXT: ret i8 %[[DISCR]]
#[no_mangle]
pub fn discriminant6(e: Tricky) -> u8 {
    std::intrinsics::discriminant_value(&e) as _
}

// Case from <https://github.com/rust-lang/rust/issues/104519>,
// where sign-extension is important.

pub enum OpenResult {
    Ok(()),
    Err(()),
    TransportErr(TransportErr),
}

#[repr(i32)]
pub enum TransportErr {
    UnknownMethod = -2,
}

#[no_mangle]
pub fn match7(result: OpenResult) -> u8 {
    // CHECK-LABEL: define noundef{{( range\(i8 [0-9]+, [0-9]+\))?}} i8 @match7(i32{{.+}}%result)
    // CHECK-NEXT: start:
    // CHECK-NEXT: %[[NOT_OK:.+]] = icmp ne i32 %result, -1
    // CHECK-NEXT: %[[RET:.+]] = zext i1 %[[NOT_OK]] to i8
    // CHECK-NEXT: ret i8 %[[RET]]
    match result {
        OpenResult::Ok(()) => 0,
        _ => 1,
    }
}