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SILOptimizer: Fix mandatory switch dispatch elimination for unreachable cases #84680

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Merged
merged 1 commit into from
Oct 4, 2025
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SILOptimizer: Fix mandatory switch dispatch elimination for unreachable cases #84680

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4 changes: 1 addition & 3 deletions lib/SILOptimizer/Mandatory/DiagnoseUnreachable.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -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)) {
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63 changes: 63 additions & 0 deletions test/SILOptimizer/unavailable_enum_element_mandatory_custom_domain.swift
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@@ -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: ()
}
}