Index: lib/Analysis/ThreadSafety.cpp
===================================================================
--- lib/Analysis/ThreadSafety.cpp
+++ lib/Analysis/ThreadSafety.cpp
@@ -1450,6 +1450,14 @@
   // If the condition is a call to a Trylock function, then grab the attributes
   for (const auto *Attr : FunDecl->attrs()) {
     switch (Attr->getKind()) {
+      case attr::TryAcquireCapability: {
+        auto *A = cast<TryAcquireCapabilityAttr>(Attr);
+        getMutexIDs(A->isShared() ? SharedLocksToAdd : ExclusiveLocksToAdd, A,
+                    Exp, FunDecl, PredBlock, CurrBlock, A->getSuccessValue(),
+                    Negate);
+        CapDiagKind = ClassifyDiagnostic(A);
+        break;
+      };
       case attr::ExclusiveTrylockFunction: {
         const auto *A = cast<ExclusiveTrylockFunctionAttr>(Attr);
         getMutexIDs(ExclusiveLocksToAdd, A, Exp, FunDecl,
@@ -2249,10 +2257,13 @@
                     A, nullptr, D);
         CapDiagKind = ClassifyDiagnostic(A);
       } else if (isa<ExclusiveTrylockFunctionAttr>(Attr)) {
-        // Don't try to check trylock functions for now
+        // Don't try to check trylock functions for now.
         return;
       } else if (isa<SharedTrylockFunctionAttr>(Attr)) {
-        // Don't try to check trylock functions for now
+        // Don't try to check trylock functions for now.
+        return;
+      } else if (isa<TryAcquireCapabilityAttr>(Attr)) {
+        // Don't try to check trylock functions for now.
         return;
       }
     }
Index: test/SemaCXX/warn-thread-safety-analysis.cpp
===================================================================
--- test/SemaCXX/warn-thread-safety-analysis.cpp
+++ test/SemaCXX/warn-thread-safety-analysis.cpp
@@ -1,6 +1,7 @@
 // RUN: %clang_cc1 -fsyntax-only -verify -std=c++11 -Wthread-safety -Wthread-safety-beta -Wno-thread-safety-negative -fcxx-exceptions -DUSE_ASSERT_CAPABILITY=0 %s
 // RUN: %clang_cc1 -fsyntax-only -verify -std=c++11 -Wthread-safety -Wthread-safety-beta -Wno-thread-safety-negative -fcxx-exceptions -DUSE_ASSERT_CAPABILITY=1 %s
 // RUN: %clang_cc1 -fsyntax-only -verify -std=c++17 -Wthread-safety -Wthread-safety-beta -Wno-thread-safety-negative -fcxx-exceptions -DUSE_ASSERT_CAPABILITY=0 %s
+// RUN: %clang_cc1 -fsyntax-only -verify -std=c++17 -Wthread-safety -Wthread-safety-beta -Wno-thread-safety-negative -fcxx-exceptions -DUSE_ASSERT_CAPABILITY=1 -DUSE_TRY_ACQUIRE_CAPABILITY %s
 
 // FIXME: should also run  %clang_cc1 -fsyntax-only -verify -Wthread-safety -std=c++11 -Wc++98-compat %s
 // FIXME: should also run  %clang_cc1 -fsyntax-only -verify -Wthread-safety %s
@@ -24,8 +25,13 @@
 #define ASSERT_SHARED_LOCK(...)         __attribute__((assert_shared_lock(__VA_ARGS__)))
 #endif
 
+#ifdef USE_TRY_ACQUIRE_CAPABILITY
+#define EXCLUSIVE_TRYLOCK_FUNCTION(...) __attribute__((try_acquire_capability(__VA_ARGS__)))
+#define SHARED_TRYLOCK_FUNCTION(...)    __attribute__((try_acquire_shared_capability(__VA_ARGS__)))
+#else
 #define EXCLUSIVE_TRYLOCK_FUNCTION(...) __attribute__((exclusive_trylock_function(__VA_ARGS__)))
 #define SHARED_TRYLOCK_FUNCTION(...)    __attribute__((shared_trylock_function(__VA_ARGS__)))
+#endif
 #define UNLOCK_FUNCTION(...)            __attribute__((unlock_function(__VA_ARGS__)))
 #define EXCLUSIVE_UNLOCK_FUNCTION(...)  __attribute__((release_capability(__VA_ARGS__)))
 #define SHARED_UNLOCK_FUNCTION(...)     __attribute__((release_shared_capability(__VA_ARGS__)))
@@ -41,8 +47,8 @@
   void Lock() __attribute__((exclusive_lock_function));
   void ReaderLock() __attribute__((shared_lock_function));
   void Unlock() __attribute__((unlock_function));
-  bool TryLock() __attribute__((exclusive_trylock_function(true)));
-  bool ReaderTryLock() __attribute__((shared_trylock_function(true)));
+  bool TryLock() EXCLUSIVE_TRYLOCK_FUNCTION(true);
+  bool ReaderTryLock() SHARED_TRYLOCK_FUNCTION(true);
   void LockWhen(const int &cond) __attribute__((exclusive_lock_function));
 
   // for negative capabilities