Merge pull request swiftlang#73236 from nate-chandler/cherrypick/release/6.0/rdar125265980

6.0: [IRGen] Deadends don't need dealloc_pack_metadata.

Author: nate-chandler

lib/IRGen/IRGenSIL.cpp

@@ -16,10 +16,10 @@
 //===----------------------------------------------------------------------===//
 
 #include "GenKeyPath.h"
-#include "swift/AST/ExtInfo.h"
 #include "swift/AST/ASTContext.h"
 #include "swift/AST/ASTMangler.h"
 #include "swift/AST/DiagnosticsIRGen.h"
+#include "swift/AST/ExtInfo.h"
 #include "swift/AST/GenericEnvironment.h"
 #include "swift/AST/IRGenOptions.h"
 #include "swift/AST/ParameterList.h"
@@ -34,6 +34,7 @@
 #include "swift/IRGen/Linking.h"
 #include "swift/SIL/ApplySite.h"
 #include "swift/SIL/BasicBlockDatastructures.h"
+#include "swift/SIL/BasicBlockUtils.h"
 #include "swift/SIL/Dominance.h"
 #include "swift/SIL/InstructionUtils.h"
 #include "swift/SIL/MemAccessUtils.h"
@@ -44,6 +45,7 @@
 #include "swift/SIL/SILLinkage.h"
 #include "swift/SIL/SILModule.h"
 #include "swift/SIL/SILType.h"
+#include "swift/SIL/SILValue.h"
 #include "swift/SIL/SILVisitor.h"
 #include "swift/SIL/TerminatorUtils.h"
 #include "clang/AST/ASTContext.h"
@@ -410,6 +412,9 @@ class IRGenSILFunction :
   /// metadata is emitted has some corresponding cleanup instructions.
   llvm::DenseMap<SILInstruction *, llvm::SmallVector<SILInstruction *, 2>>
       DynamicMetadataPackDeallocs;
+
+  // A cached dead-end blocks analysis.
+  std::unique_ptr<DeadEndBlocks> DeadEnds;
 #endif
   /// For each instruction which did allocate pack metadata on-stack, the stack
   /// locations at which they were allocated.
@@ -680,6 +685,15 @@ class IRGenSILFunction :
     return Name;
   }
 
+#ifndef NDEBUG
+  DeadEndBlocks *getDeadEndBlocks() {
+    if (!DeadEnds) {
+      DeadEnds.reset(new DeadEndBlocks(CurSILFn));
+    }
+    return DeadEnds.get();
+  }
+#endif
+
   /// To make it unambiguous whether a `var` binding has been initialized,
   /// zero-initialize the shadow copy alloca. LLDB uses the first pointer-sized
   /// field to recognize to detect uninitialized variables. This can be
@@ -2736,8 +2750,9 @@ void IRGenSILFunction::visitSILBasicBlock(SILBasicBlock *BB) {
 #ifndef NDEBUG
     if (!OutstandingStackPackAllocs.empty()) {
       auto iter = DynamicMetadataPackDeallocs.find(&I);
-      if (iter == DynamicMetadataPackDeallocs.end() ||
-          iter->getSecond().size() == 0) {
+      if ((iter == DynamicMetadataPackDeallocs.end() ||
+           iter->getSecond().size() == 0) &&
+          !getDeadEndBlocks()->isDeadEnd(I.getParent())) {
         llvm::errs()
             << "Instruction missing on-stack pack metadata cleanups!\n";
         I.print(llvm::errs());

validation-test/IRGen/gh72536.swift

@@ -0,0 +1,7 @@
+// RUN: %target-swift-emit-ir \
+// RUN:     %s                \
+// RUN:     -disable-availability-checking
+
+func foo<each S>(_ s: repeat each S) async {}
+await foo(true)
+