SimplifyApply: don't do the raw-enum comparison optimization for custom RawRepresentable enums

SwiftCompilerSources/Sources/AST/Declarations.swift

@@ -58,7 +58,9 @@ public class NominalTypeDecl: GenericTypeDecl {
   }
 }
 
-final public class EnumDecl: NominalTypeDecl {}
+final public class EnumDecl: NominalTypeDecl {
+  public var hasRawType: Bool { bridged.Enum_hasRawType() }
+}
 
 final public class StructDecl: NominalTypeDecl {
   public var hasUnreferenceableStorage: Bool { bridged.Struct_hasUnreferenceableStorage() }

SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyApply.swift

@@ -135,6 +135,7 @@ private func tryOptimizeEnumComparison(apply: ApplyInst, _ context: SimplifyCont
   let lhs = apply.arguments[0]
   let rhs = apply.arguments[1]
   guard let enumDecl = lhs.type.nominal as? EnumDecl,
+        enumDecl.hasRawType,
         !enumDecl.isResilient(in: apply.parentFunction),
         !enumDecl.hasClangNode,
         lhs.type.isAddress,

include/swift/AST/ASTBridging.h

@@ -402,6 +402,7 @@ struct BridgedDeclObj {
   BRIDGED_INLINE bool GenericType_isGenericAtAnyLevel() const;
   BRIDGED_INLINE bool NominalType_isGlobalActor() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE OptionalBridgedDeclObj NominalType_getValueTypeDestructor() const;
+  BRIDGED_INLINE bool Enum_hasRawType() const;
   BRIDGED_INLINE bool Struct_hasUnreferenceableStorage() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedASTType Class_getSuperclass() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedDeclObj Class_getDestructor() const;

include/swift/AST/ASTBridgingImpl.h

@@ -221,6 +221,10 @@ OptionalBridgedDeclObj BridgedDeclObj::NominalType_getValueTypeDestructor() cons
   return {getAs<swift::NominalTypeDecl>()->getValueTypeDestructor()};
 }
 
+bool BridgedDeclObj::Enum_hasRawType() const {
+  return getAs<swift::EnumDecl>()->hasRawType();
+}
+
 bool BridgedDeclObj::Struct_hasUnreferenceableStorage() const {
   return getAs<swift::StructDecl>()->hasUnreferenceableStorage();
 }

test/SILOptimizer/enum-comparison.swift

@@ -80,6 +80,28 @@ func compare4(_ x: LargeEnum) -> Bool {
   return x == .e3(28)
 }
 
+enum CustomRawValue: RawRepresentable {
+  case a, b, c
+
+  init(rawValue: Int) {
+    self = .a
+  }
+
+  @inline(never)
+  var rawValue: Int {
+    print(0)
+    return 0
+  }
+}
+
+// CHECK-LABEL: define {{.*}} i1 @"$s4test8compare5ySbAA14CustomRawValueOF"(i8 %0)
+// CHECK:       entry:
+// CHECK-NEXT:    call
+@inline(never)
+func compare5(_ x: CustomRawValue) -> Bool {
+  return x == .b
+}
+
 // OUT: 1: false
 print("1: \(compareeq(.c, .long_case_name_for_testing))")
 
@@ -116,3 +138,6 @@ print("11: \(compare4(.e3(28)))")
 // OUT: 12: false
 print("12: \(compare4(.e3(27)))")
 
+// OUT: 13: true
+print("13: \(compare5(.a))")
+