rust/tests/codegen/enum-match.rs

// compile-flags: -Copt-level=1
// only-x86_64

#![crate_type = "lib"]

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

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

// CHECK: define i8 @match0{{.*}}
// CHECK-NEXT: start:
// CHECK-NEXT: %1 = icmp eq i8 %0, 2
// CHECK-NEXT: %2 = and i8 %0, 1
// CHECK-NEXT: %.0 = select i1 %1, i8 13, i8 %2
#[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: define i8 @match1{{.*}}
// CHECK-NEXT: start:
// CHECK-NEXT: [[DISCR:%.*]] = {{.*}}call i8 @llvm.usub.sat.i8(i8 %0, i8 1)
// CHECK-NEXT: switch i8 [[DISCR]], label {{.*}} [
#[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.
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: define i8 @match2{{.*}}
// CHECK-NEXT: start:
// CHECK-NEXT: %1 = add i8 %0, 2
// CHECK-NEXT: %2 = zext i8 %1 to i64
// CHECK-NEXT: %3 = icmp ult i8 %1, 4
// CHECK-NEXT: %4 = add nuw nsw i64 %2, 1
// CHECK-NEXT: %_2 = select i1 %3, i64 %4, i64 0
// CHECK-NEXT: switch i64 %_2, label {{.*}} [
#[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,
    }
}