Revert "Concurrency: remove workaround for silencing UB"

stdlib/public/Concurrency/Task.cpp

@@ -35,7 +35,6 @@
 #include "swift/Runtime/EnvironmentVariables.h"
 #include "swift/Runtime/HeapObject.h"
 #include "swift/Runtime/Heap.h"
-#include "swift/Runtime/STLCompatibility.h"
 #include "swift/Threading/Mutex.h"
 #include <atomic>
 #include <new>
@@ -1059,6 +1058,8 @@ swift_task_create_commonImpl(size_t rawTaskCreateFlags,
   // Initialize the parent context pointer to null.
   initialContext->Parent = nullptr;
 
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wcast-function-type-mismatch"
   // Initialize the resumption funclet pointer (async return address) to
   // the final funclet for completing the task.
 
@@ -1072,20 +1073,21 @@ swift_task_create_commonImpl(size_t rawTaskCreateFlags,
   // The final funclet shouldn't release the task or the task function.
   } else if (asyncLet) {
     initialContext->ResumeParent =
-        std::bit_cast<TaskContinuationFunction *>(&completeTask);
+      reinterpret_cast<TaskContinuationFunction*>(&completeTask);
 
   // If we have a non-null closure context and the task function is not
   // consumed by calling it, use a final funclet that releases both the
   // task and the closure context.
   } else if (closureContext && !taskCreateFlags.isTaskFunctionConsumed()) {
     initialContext->ResumeParent =
-        std::bit_cast<TaskContinuationFunction *>(&completeTaskWithClosure);
+      reinterpret_cast<TaskContinuationFunction*>(&completeTaskWithClosure);
 
   // Otherwise, just release the task.
   } else {
     initialContext->ResumeParent =
-        std::bit_cast<TaskContinuationFunction *>(&completeTaskAndRelease);
+      reinterpret_cast<TaskContinuationFunction*>(&completeTaskAndRelease);
   }
+#pragma clang diagnostic pop
 
   // Initialize the task-local allocator and our other private runtime
   // state for the task.

test/embedded/dependencies-concurrency-custom-executor.swift

@@ -18,7 +18,6 @@
 // DEP: _exit
 // DEP: _free
 // DEP: _malloc
-// DEP: _memcpy
 // DEP: _memmove
 // DEP: _memset
 // DEP: _memset_s

test/embedded/dependencies-concurrency.swift

@@ -18,7 +18,6 @@
 // DEP: _exit
 // DEP: _free
 // DEP: _malloc
-// DEP: _memcpy
 // DEP: _memmove
 // DEP: _memset
 // DEP: _memset_s

test/embedded/dependencies-concurrency2.swift

@@ -16,7 +16,6 @@
 // DEP: _exit
 // DEP: _free
 // DEP: _malloc
-// DEP: _memcpy
 // DEP: _memmove
 // DEP: _memset
 // DEP: _memset_s