Merge pull request #84680 from tshortli/switch-dispatch-mandatory-optimization-for-custom-availability

SILOptimizer: Fix mandatory switch dispatch elimination for unreachable cases

Author: tshortli

lib/SILOptimizer/Mandatory/DiagnoseUnreachable.cpp

@@ -926,9 +926,7 @@ static bool eliminateSwitchDispatchOnUnavailableElements(
   SmallVector<std::pair<EnumElementDecl *, SILBasicBlock *>, 4> NewCaseBBs;
   for (unsigned i : range(SWI.getNumCases())) {
     auto CaseBB = SWI.getCase(i);
-    auto availableAtr = CaseBB.first->getUnavailableAttr();
-
-    if (availableAtr && availableAtr->isUnconditionallyUnavailable()) {
+    if (!CaseBB.first->isAvailableDuringLowering()) {
       // Mark the basic block as potentially unreachable.
       SILBasicBlock *UnreachableBlock = CaseBB.second;
       if (!State->PossiblyUnreachableBlocks.contains(UnreachableBlock)) {

test/SILOptimizer/unavailable_enum_element_mandatory_custom_domain.swift

@@ -0,0 +1,63 @@
+// RUN: %target-swift-emit-sil -module-name Test %s -verify -parse-as-library \
+// RUN:   -enable-experimental-feature CustomAvailability \
+// RUN:   -define-enabled-availability-domain EnabledDomain \
+// RUN:   -define-always-enabled-availability-domain AlwaysEnabledDomain \
+// RUN:   -define-disabled-availability-domain DisabledDomain \
+// RUN:   -define-dynamic-availability-domain DynamicDomain \
+// RUN:   -Onone \
+// RUN:   | %FileCheck %s --check-prefixes=CHECK,CHECK-NOOPT
+
+// REQUIRES: swift_feature_CustomAvailability
+
+public enum Enum {
+  case alwaysAvailable
+
+  @available(*, unavailable)
+  case alwaysUnavailable
+
+  @available(EnabledDomain)
+  case enabled
+
+  @available(EnabledDomain, unavailable)
+  case enabledUnavailable
+
+  @available(AlwaysEnabledDomain)
+  case alwaysEnabled
+
+  @available(AlwaysEnabledDomain, unavailable)
+  case alwaysEnabledUnavailable
+
+  @available(DisabledDomain)
+  case disabled
+
+  @available(DisabledDomain, unavailable)
+  case disabledUnavailable
+
+  @available(DynamicDomain)
+  case dynamic
+
+  @available(DynamicDomain, unavailable)
+  case dynamicUnavailable
+}
+
+// CHECK-LABEL: sil @$s4Test22testFullyCoveredSwitchyyAA4EnumOF : $@convention(thin) (Enum) -> () {
+// CHECK:         switch_enum %0, case #Enum.alwaysAvailable!enumelt: {{bb[0-9]+}}, case #Enum.alwaysUnavailable!enumelt: {{bb[0-9]+}}, case #Enum.enabled!enumelt: {{bb[0-9]+}}, case #Enum.alwaysEnabled!enumelt: {{bb[0-9]+}}, case #Enum.disabledUnavailable!enumelt: {{bb[0-9]+}}, case #Enum.dynamic!enumelt: {{bb[0-9]+}}, case #Enum.dynamicUnavailable!enumelt: {{bb[0-9]+}}, default [[DEFAULTBB:bb[0-9]+]]
+// CHECK:       [[DEFAULTBB]]:
+// CHECK-NEXT:    integer_literal $Builtin.Int1, -1
+// CHECK-NEXT:    cond_fail {{%.*}}, "unexpected enum value"
+// CHECK-NEXT:    unreachable
+// CHECK:       } // end sil function '$s4Test22testFullyCoveredSwitchyyAA4EnumOF'
+public func testFullyCoveredSwitch(_ e: Enum) {
+  switch e {
+  case .alwaysAvailable: ()
+  case .alwaysUnavailable: ()
+  case .enabled: ()
+  case .enabledUnavailable: ()
+  case .alwaysEnabled: ()
+  case .alwaysEnabledUnavailable: ()
+  case .disabled: ()
+  case .disabledUnavailable: ()
+  case .dynamic: ()
+  case .dynamicUnavailable: ()
+  }
+}