Merge pull request #61950 from nate-chandler/opaque-values/1/20221105

[AddressLowering] Handle multidefault switch_enum.

Author: nate-chandler

lib/SILOptimizer/Mandatory/AddressLowering.cpp

@@ -3011,7 +3011,7 @@ void UseRewriter::visitSwitchEnumInst(SwitchEnumInst * switchEnum) {
       return;
 
     assert(caseBB->getArguments().size() == 1);
-    SILArgument *caseArg = caseBB->getArguments()[0];
+    SILArgument *caseArg = caseBB->getArgument(0);
 
     assert(&switchEnum->getOperandRef(0) == getReusedStorageOperand(caseArg));
     assert(caseDecl->hasAssociatedValues() && "caseBB has a payload argument");
@@ -3053,6 +3053,20 @@ void UseRewriter::visitSwitchEnumInst(SwitchEnumInst * switchEnum) {
     defaultCounter = switchEnum->getDefaultCount();
     if (auto defaultDecl = switchEnum->getUniqueCaseForDefault()) {
       rewriteCase(defaultDecl.get(), defaultBB);
+    } else {
+      assert(defaultBB->getArguments().size() == 1);
+      SILArgument *arg = defaultBB->getArgument(0);
+      assert(arg->getType().isAddressOnly(*pass.function));
+      auto builder = pass.getBuilder(defaultBB->begin());
+      auto addr = enumAddr;
+      auto *load = builder.createTrivialLoadOr(switchEnum->getLoc(), addr,
+                                               LoadOwnershipQualifier::Take);
+      // Remap arg to the new dummy load which will be deleted during
+      // deleteRewrittenInstructions.
+      arg->replaceAllUsesWith(load);
+      pass.valueStorageMap.replaceValue(arg, load);
+      markRewritten(load, addr);
+      defaultBB->eraseArgument(0);
     }
   }
   auto builder = pass.getTermBuilder(switchEnum);

test/SILOptimizer/address_lowering.sil

@@ -1130,6 +1130,24 @@ bb4:
   return %31 : $()
 }
 
+// Verify the handling of non-unique default case blocks when there is more
+// than one case handled by default.
+// CHECK-LABEL: sil [ossa] @f221_testSwitchDefault : $@convention(thin) <T> (@in Optional<T>) -> () {
+// CHECK:       {{bb[0-9]+}}([[INSTANCE:%[^,]+]] : $*Optional<T>):
+// CHECK:         switch_enum_addr [[INSTANCE]] : $*Optional<T>, default [[EXIT:bb[0-9]+]]
+// CHECK:       [[EXIT]]:
+// CHECK:         destroy_addr [[INSTANCE]] : $*Optional<T>
+// CHECK-LABEL: } // end sil function 'f221_testSwitchDefault'
+sil [ossa] @f221_testSwitchDefault : $@convention(thin) <T> (@in Optional<T>) -> () {
+entry(%instance : @owned $Optional<T>):
+  switch_enum %instance : $Optional<T>, default exit
+
+exit(%instance_2 : @owned $Optional<T>):
+  destroy_value %instance_2 : $Optional<T>
+  %retval = tuple ()
+  return %retval : $()
+}
+
 // CHECK-LABEL: sil [ossa] @f230_testTryApply : $@convention(thin) <T> (@in T) -> (@out T, @error any Error) {
 // CHECK: bb0(%0 : $*T, %1 : $*T):
 // CHECK:   [[F:%.*]] = function_ref @throwsError : $@convention(thin) <τ_0_0> (@in τ_0_0) -> (@out τ_0_0, @error any Error)