Open Radar

 
Summary:
Compiler crashes if conditions of the case clause are duplicated in the initializer.
For example: Conforming to RawRepresentable protocol

Steps to Reproduce:
1. Define following enum
2. Set build configuration in scheme to 'Release'
3. Build it

public enum Enum {
    case A
    case B
    case C
}

extension Enum : RawRepresentable {

    public init?(rawValue: Int) {
        switch rawValue {
        case 0:
            self = A
        case 1:
            self = B
        case 1:
            self = B
        default:
            self = C
        }
    }

    public var rawValue: Int {
        switch self {
        case A:
            return 0
        case B:
            return 1
        default:
            return 2
        }
    }
}

Expected Results:
Build succeeded

Actual Results:
Build failed due to following error:
Command failed due to signal: Illegal instruction: 4

SIL verification failed: select_value dispatches on same case value more than once: !seenCaseValues.count(elt)
Verifying instruction:
     %4 = load %3 : $*Builtin.Int64               // user: %10
     %5 = integer_literal $Builtin.Int64, 0       // user: %10
     %6 = enum $Enum, #Enum.A!enumelt             // user: %10
     %7 = integer_literal $Builtin.Int64, 1       // users: %10, %10
     %7 = integer_literal $Builtin.Int64, 1       // users: %10, %10
     %8 = enum $Enum, #Enum.B!enumelt             // users: %10, %10
     %8 = enum $Enum, #Enum.B!enumelt             // users: %10, %10
     %9 = enum $Enum, #Enum.C!enumelt             // user: %10
->   %10 = select_value %4 : $Builtin.Int64, case %5: %6, case %7: %8, case %7: %8, default %9 : $Enum // user: %11
     %11 = enum $Optional<Enum>, #Optional.Some!enumelt.1, %10 : $Enum // user: %12
In function:
// protocol witness for Swift.RawRepresentable.init <A where A: Swift.RawRepresentable> (A.Type)(rawValue : A.RawValue) -> Swift.Optional<A> in conformance EnumTest.Enum : Swift.RawRepresentable in EnumTest
sil [transparent] [thunk] @_TTWO8EnumTest4EnumSs16RawRepresentableS_FS1_CuRq_S1__fMq_FT8rawValueqq_S1_8RawValue_GSqq__ : $@convention(witness_method) (@out Optional<Enum>, @in Int, @thick Enum.Type) -> () {
bb0(%0 : $*Optional<Enum>, %1 : $*Int, %2 : $@thick Enum.Type):
  %3 = struct_element_addr %1 : $*Int, #Int.value // user: %4
  %4 = load %3 : $*Builtin.Int64                  // user: %10
  %5 = integer_literal $Builtin.Int64, 0          // user: %10
  %6 = enum $Enum, #Enum.A!enumelt                // user: %10
  %7 = integer_literal $Builtin.Int64, 1          // users: %10, %10
  %8 = enum $Enum, #Enum.B!enumelt                // users: %10, %10
  %9 = enum $Enum, #Enum.C!enumelt                // user: %10
  %10 = select_value %4 : $Builtin.Int64, case %5: %6, case %7: %8, case %7: %8, default %9 : $Enum // user: %11
  %11 = enum $Optional<Enum>, #Optional.Some!enumelt.1, %10 : $Enum // user: %12
  store %11 to %0 : $*Optional<Enum>              // id: %12
  %13 = tuple ()                                  // user: %14
  return %13 : $()                                // id: %14
}

Version:
OS X 10.10.3 (14D136), Version 7.0 beta (7A121l)
OS X 10.11 (15A204h), Version 7.0 beta (7A120f)

Notes:
This crash is occurred RELEASE build only

Configuration:
MacBookPro10,1, 16GB RAM
MacBook8,1, 8GB RAM

Attachments: