diff --git a/cmake/modules/AddSwift.cmake b/cmake/modules/AddSwift.cmake
index 7b8ac7a995eba..6f590663b20af 100644
--- a/cmake/modules/AddSwift.cmake
+++ b/cmake/modules/AddSwift.cmake
@@ -730,7 +730,8 @@ function(_add_swift_library_single target name)
         OBJECT_LIBRARY
         SHARED
         STATIC
-        TARGET_LIBRARY)
+        TARGET_LIBRARY
+        INSTALL_WITH_SHARED)
   set(SWIFTLIB_SINGLE_single_parameter_options
         ARCHITECTURE
         DEPLOYMENT_VERSION_IOS
@@ -1085,18 +1086,24 @@ function(_add_swift_library_single target name)
         BINARY_DIR ${SWIFT_RUNTIME_OUTPUT_INTDIR}
         LIBRARY_DIR ${SWIFT_LIBRARY_OUTPUT_INTDIR})
 
+    if(SWIFTLIB_INSTALL_WITH_SHARED)
+      set(swift_lib_dir ${SWIFTLIB_DIR})
+    else()
+      set(swift_lib_dir ${SWIFTSTATICLIB_DIR})
+    endif()
+
     foreach(config ${CMAKE_CONFIGURATION_TYPES})
       string(TOUPPER ${config} config_upper)
       escape_path_for_xcode(
-          "${config}" "${SWIFTSTATICLIB_DIR}" config_lib_dir)
+          "${config}" "${swift_lib_dir}" config_lib_dir)
       set_target_properties(${target_static} PROPERTIES
         LIBRARY_OUTPUT_DIRECTORY_${config_upper} ${config_lib_dir}/${SWIFTLIB_SINGLE_SUBDIR}
         ARCHIVE_OUTPUT_DIRECTORY_${config_upper} ${config_lib_dir}/${SWIFTLIB_SINGLE_SUBDIR})
     endforeach()
 
     set_target_properties(${target_static} PROPERTIES
-      LIBRARY_OUTPUT_DIRECTORY ${SWIFTSTATICLIB_DIR}/${SWIFTLIB_SINGLE_SUBDIR}
-      ARCHIVE_OUTPUT_DIRECTORY ${SWIFTSTATICLIB_DIR}/${SWIFTLIB_SINGLE_SUBDIR})
+      LIBRARY_OUTPUT_DIRECTORY ${swift_lib_dir}/${SWIFTLIB_SINGLE_SUBDIR}
+      ARCHIVE_OUTPUT_DIRECTORY ${swift_lib_dir}/${SWIFTLIB_SINGLE_SUBDIR})
   endif()
 
   set_target_properties(${target}
@@ -1347,8 +1354,14 @@ function(_add_swift_library_single target name)
     set_property(TARGET "${target_static}" APPEND_STRING PROPERTY
         COMPILE_FLAGS " ${c_compile_flags}")
     # FIXME: The fallback paths here are going to be dynamic libraries.
+
+    if(SWIFTLIB_INSTALL_WITH_SHARED)
+      set(search_base_dir ${SWIFTLIB_DIR})
+    else()
+      set(search_base_dir ${SWIFTSTATICLIB_DIR})
+    endif()
     set(library_search_directories
-        "${SWIFTSTATICLIB_DIR}/${SWIFTLIB_SINGLE_SUBDIR}"
+        "${search_base_dir}/${SWIFTLIB_SINGLE_SUBDIR}"
         "${SWIFT_NATIVE_SWIFT_TOOLS_PATH}/../lib/swift/${SWIFTLIB_SINGLE_SUBDIR}"
         "${SWIFT_NATIVE_SWIFT_TOOLS_PATH}/../lib/swift/${SWIFT_SDK_${SWIFTLIB_SINGLE_SDK}_LIB_SUBDIR}")
     swift_target_link_search_directories("${target_static}" "${library_search_directories}")
@@ -1477,6 +1490,7 @@ endfunction()
 #     [IS_STDLIB]
 #     [IS_STDLIB_CORE]
 #     [TARGET_LIBRARY]
+#     [INSTALL_WITH_SHARED]
 #     INSTALL_IN_COMPONENT comp
 #     DEPLOYMENT_VERSION_OSX version
 #     DEPLOYMENT_VERSION_IOS version
@@ -1583,6 +1597,9 @@ endfunction()
 # DEPLOYMENT_VERSION_WATCHOS
 #   The minimum deployment version to build for if this is an WATCHOS library.
 #
+# INSTALL_WITH_SHARED
+#   Install a static library target alongside shared libraries
+#
 # source1 ...
 #   Sources to add into this library.
 function(add_swift_target_library name)
@@ -1597,7 +1614,8 @@ function(add_swift_target_library name)
         OBJECT_LIBRARY
         SHARED
         STATIC
-        TARGET_LIBRARY)
+        TARGET_LIBRARY
+        INSTALL_WITH_SHARED)
   set(SWIFTLIB_single_parameter_options
         DEPLOYMENT_VERSION_IOS
         DEPLOYMENT_VERSION_OSX
@@ -1882,6 +1900,7 @@ function(add_swift_target_library name)
         ${SWIFTLIB_SHARED_keyword}
         ${SWIFTLIB_STATIC_keyword}
         ${SWIFTLIB_OBJECT_LIBRARY_keyword}
+        ${SWIFTLIB_INSTALL_WITH_SHARED_keyword}
         ${SWIFTLIB_SOURCES}
         MODULE_TARGET ${MODULE_VARIANT_NAME}
         SDK ${sdk}
@@ -1996,7 +2015,7 @@ function(add_swift_target_library name)
       set(resource_dir_sdk_subdir "${SWIFT_SDK_${sdk}_LIB_SUBDIR}")
       precondition(resource_dir_sdk_subdir)
 
-      if(SWIFTLIB_SHARED)
+      if(SWIFTLIB_SHARED OR SWIFTLIB_INSTALL_WITH_SHARED)
         set(resource_dir "swift")
         set(file_permissions
             OWNER_READ OWNER_WRITE OWNER_EXECUTE
@@ -2058,10 +2077,18 @@ function(add_swift_target_library name)
           list(APPEND THIN_INPUT_TARGETS_STATIC "${TARGET}-static")
         endforeach()
 
+        if(SWIFTLIB_INSTALL_WITH_SHARED)
+          set(install_subdir "swift")
+          set(universal_subdir ${SWIFTLIB_DIR})
+        else()
+          set(install_subdir "swift_static")
+          set(universal_subdir ${SWIFTSTATICLIB_DIR})
+        endif()
+
         set(lipo_target_static
             "${name}-${SWIFT_SDK_${sdk}_LIB_SUBDIR}-static")
         set(UNIVERSAL_LIBRARY_NAME
-            "${SWIFTSTATICLIB_DIR}/${SWIFT_SDK_${sdk}_LIB_SUBDIR}/${CMAKE_STATIC_LIBRARY_PREFIX}${name}${CMAKE_STATIC_LIBRARY_SUFFIX}")
+            "${universal_subdir}/${SWIFT_SDK_${sdk}_LIB_SUBDIR}/${CMAKE_STATIC_LIBRARY_PREFIX}${name}${CMAKE_STATIC_LIBRARY_SUFFIX}")
         _add_swift_lipo_target(SDK
                                  ${sdk}
                                TARGET
@@ -2070,7 +2097,7 @@ function(add_swift_target_library name)
                                  "${UNIVERSAL_LIBRARY_NAME}"
                                ${THIN_INPUT_TARGETS_STATIC})
         swift_install_in_component(FILES "${UNIVERSAL_LIBRARY_NAME}"
-                                   DESTINATION "lib${LLVM_LIBDIR_SUFFIX}/swift_static/${resource_dir_sdk_subdir}"
+                                   DESTINATION "lib${LLVM_LIBDIR_SUFFIX}/${install_subdir}/${resource_dir_sdk_subdir}"
                                    PERMISSIONS
                                      OWNER_READ OWNER_WRITE
                                      GROUP_READ
diff --git a/cmake/modules/SwiftSource.cmake b/cmake/modules/SwiftSource.cmake
index 2ddc724f1649d..9eeef768b586f 100644
--- a/cmake/modules/SwiftSource.cmake
+++ b/cmake/modules/SwiftSource.cmake
@@ -253,12 +253,10 @@ function(_compile_swift_files
     list(APPEND swift_flags "-module-name" "${SWIFTFILE_MODULE_NAME}")
   endif()
 
-  # Force swift 5 mode for Standard Library.
+  # Force swift 5 mode for Standard Library and overlays.
   if (SWIFTFILE_IS_STDLIB)
     list(APPEND swift_flags "-swift-version" "5")
   endif()
-
-  # Force swift 4 compatibility mode for overlays.
   if (SWIFTFILE_IS_SDK_OVERLAY)
     list(APPEND swift_flags "-swift-version" "5")
   endif()
@@ -267,6 +265,12 @@ function(_compile_swift_files
     list(APPEND swift_flags "-autolink-force-load")
   endif()
 
+  # Don't need to link runtime compatibility libraries for older runtimes 
+  # into the new runtime.
+  if (SWIFTFILE_IS_STDLIB OR SWIFTFILE_IS_SDK_OVERLAY)
+    list(APPEND swift_flags "-runtime-compatibility-version" "none")
+  endif()
+
   if (SWIFTFILE_IS_STDLIB_CORE OR SWIFTFILE_IS_SDK_OVERLAY)
     list(APPEND swift_flags "-warn-swift3-objc-inference-complete")
   endif()
diff --git a/include/swift/AST/IRGenOptions.h b/include/swift/AST/IRGenOptions.h
index bfb330e767756..fe9f08e0e4695 100644
--- a/include/swift/AST/IRGenOptions.h
+++ b/include/swift/AST/IRGenOptions.h
@@ -26,6 +26,7 @@
 // FIXME: This include is just for llvm::SanitizerCoverageOptions. We should
 // split the header upstream so we don't include so much.
 #include "llvm/Transforms/Instrumentation.h"
+#include "llvm/Support/VersionTuple.h"
 #include <string>
 #include <vector>
 
@@ -224,6 +225,9 @@ class IRGenOptions {
   };
 
   TypeInfoDumpFilter TypeInfoFilter;
+  
+  /// Pull in runtime compatibility shim libraries by autolinking.
+  Optional<llvm::VersionTuple> AutolinkRuntimeCompatibilityLibraryVersion;
 
   IRGenOptions()
       : DWARFVersion(2), OutputKind(IRGenOutputKind::LLVMAssembly),
diff --git a/include/swift/Basic/Platform.h b/include/swift/Basic/Platform.h
index d59ef72e4297d..134b7a2cd43c6 100644
--- a/include/swift/Basic/Platform.h
+++ b/include/swift/Basic/Platform.h
@@ -19,6 +19,7 @@
 
 namespace llvm {
   class Triple;
+  class VersionTuple;
 }
 
 namespace swift {
@@ -85,6 +86,12 @@ namespace swift {
   /// The input triple should already be "normalized" in the sense that
   /// llvm::Triple::normalize() would not affect it.
   llvm::Triple getTargetSpecificModuleTriple(const llvm::Triple &triple);
+  
+  
+  /// Get the Swift runtime version to deploy back to, given a deployment target expressed as an
+  /// LLVM target triple.
+  Optional<llvm::VersionTuple>
+  getSwiftRuntimeCompatibilityVersionForTarget(const llvm::Triple &Triple);
 } // end namespace swift
 
 #endif // SWIFT_BASIC_PLATFORM_H
diff --git a/include/swift/Option/Options.td b/include/swift/Option/Options.td
index 53f8d3401a84d..c6f32a0d6bb32 100644
--- a/include/swift/Option/Options.td
+++ b/include/swift/Option/Options.td
@@ -892,4 +892,9 @@ def vfsoverlay_EQ : Joined<["-"], "vfsoverlay=">,
 def runtime_compatibility_version : Separate<["-"], "runtime-compatibility-version">,
   Flags<[FrontendOption]>,
   HelpText<"Link compatibility library for Swift runtime version, or 'none'">;
+
+def disable_autolinking_runtime_compatibility : Flag<["-"], "disable-autolinking-runtime-compatibility">,
+  Flags<[FrontendOption]>,
+  HelpText<"Do not use autolinking for runtime compatibility libraries">;
+
 include "FrontendOptions.td"
diff --git a/lib/Basic/Platform.cpp b/lib/Basic/Platform.cpp
index c385d666028c9..90bc7d52cc203 100644
--- a/lib/Basic/Platform.cpp
+++ b/lib/Basic/Platform.cpp
@@ -14,6 +14,7 @@
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/ADT/StringSwitch.h"
 #include "llvm/ADT/Triple.h"
+#include "llvm/Support/VersionTuple.h"
 
 using namespace swift;
 
@@ -313,3 +314,37 @@ llvm::Triple swift::getTargetSpecificModuleTriple(const llvm::Triple &triple) {
   return triple;
 }
 
+Optional<llvm::VersionTuple>
+swift::getSwiftRuntimeCompatibilityVersionForTarget(const llvm::Triple &Triple){
+  unsigned Major, Minor, Micro;
+  
+  if (Triple.isMacOSX()) {
+    Triple.getMacOSXVersion(Major, Minor, Micro);
+    if (Major == 10) {
+      if (Minor <= 14) {
+        return llvm::VersionTuple(5, 0);
+      } else {
+        return None;
+      }
+    } else {
+      return None;
+    }
+  } else if (Triple.isiOS()) { // includes tvOS
+    Triple.getiOSVersion(Major, Minor, Micro);
+    if (Major <= 12) {
+      return llvm::VersionTuple(5, 0);
+    } else {
+      return None;
+    }
+  } else if (Triple.isWatchOS()) {
+    Triple.getWatchOSVersion(Major, Minor, Micro);
+    if (Major <= 5) {
+      return llvm::VersionTuple(5, 0);
+    } else {
+      return None;
+    }
+  } else {
+    return None;
+  }
+}
+
diff --git a/lib/Driver/DarwinToolChains.cpp b/lib/Driver/DarwinToolChains.cpp
index 738089e27c954..2c10be0348c52 100644
--- a/lib/Driver/DarwinToolChains.cpp
+++ b/lib/Driver/DarwinToolChains.cpp
@@ -33,6 +33,7 @@
 #include "llvm/Support/Path.h"
 #include "llvm/Support/Process.h"
 #include "llvm/Support/Program.h"
+#include "llvm/Support/VersionTuple.h"
 
 using namespace swift;
 using namespace swift::driver;
@@ -221,42 +222,6 @@ static bool wantsObjCRuntime(const llvm::Triple &triple) {
   llvm_unreachable("unknown Darwin OS");
 }
 
-/// Return the earliest backward deployment compatibility version we need to
-/// link in for the given target triple, if any.
-static Optional<std::pair<unsigned, unsigned>>
-getSwiftRuntimeCompatibilityVersionForTarget(const llvm::Triple &Triple) {
-  unsigned Major, Minor, Micro;
-  
-  if (Triple.isMacOSX()) {
-    Triple.getMacOSXVersion(Major, Minor, Micro);
-    if (Major == 10) {
-      if (Minor <= 14) {
-        return std::make_pair(5u, 0u);
-      } else {
-        return None;
-      }
-    } else {
-      return None;
-    }
-  } else if (Triple.isiOS()) { // includes tvOS
-    Triple.getiOSVersion(Major, Minor, Micro);
-    if (Major <= 12) {
-      return std::make_pair(5u, 0u);
-    } else {
-      return None;
-    }
-  } else if (Triple.isWatchOS()) {
-    Triple.getWatchOSVersion(Major, Minor, Micro);
-    if (Major <= 5) {
-      return std::make_pair(5u, 0u);
-    } else {
-      return None;
-    }
-  } else {
-    return None;
-  }
-}
-
 ToolChain::InvocationInfo
 toolchains::Darwin::constructInvocation(const LinkJobAction &job,
                                         const JobContext &context) const
@@ -431,12 +396,13 @@ toolchains::Darwin::constructInvocation(const LinkJobAction &job,
 
   // Link compatibility libraries, if we're deploying back to OSes that
   // have an older Swift runtime.
-  Optional<std::pair<unsigned, unsigned>> runtimeCompatibilityVersion;
+  Optional<llvm::VersionTuple> runtimeCompatibilityVersion;
   
   if (context.Args.hasArg(options::OPT_runtime_compatibility_version)) {
-    auto value = context.Args.getLastArgValue(options::OPT_runtime_compatibility_version);
+    auto value = context.Args.getLastArgValue(
+                                    options::OPT_runtime_compatibility_version);
     if (value.equals("5.0")) {
-      runtimeCompatibilityVersion = std::make_pair(5u, 0u);
+      runtimeCompatibilityVersion = llvm::VersionTuple(5, 0);
     } else if (value.equals("none")) {
       runtimeCompatibilityVersion = None;
     } else {
@@ -448,7 +414,7 @@ toolchains::Darwin::constructInvocation(const LinkJobAction &job,
   }
   
   if (runtimeCompatibilityVersion) {
-    if (*runtimeCompatibilityVersion <= std::make_pair(5u, 0u)) {
+    if (*runtimeCompatibilityVersion <= llvm::VersionTuple(5, 0)) {
       // Swift 5.0 compatibility library
       SmallString<128> BackDeployLib;
       BackDeployLib.append(RuntimeLibPath);
diff --git a/lib/Driver/ToolChains.cpp b/lib/Driver/ToolChains.cpp
index ad75b4b454f50..9c377c066bbe6 100644
--- a/lib/Driver/ToolChains.cpp
+++ b/lib/Driver/ToolChains.cpp
@@ -433,6 +433,17 @@ ToolChain::constructInvocation(const CompileJobAction &job,
     Arguments.push_back("-debug-info-store-invocation");
   }
 
+  if (context.Args.hasArg(
+                      options::OPT_disable_autolinking_runtime_compatibility)) {
+    Arguments.push_back("-disable-autolinking-runtime-compatibility");
+  }
+                                 
+  if (auto arg = context.Args.getLastArg(
+                                  options::OPT_runtime_compatibility_version)) {
+    Arguments.push_back("-runtime-compatibility-version");
+    Arguments.push_back(arg->getValue());
+  }
+                                 
   return II;
 }
 
diff --git a/lib/Frontend/CompilerInvocation.cpp b/lib/Frontend/CompilerInvocation.cpp
index 8e8945bc6e228..116b426e9f0bb 100644
--- a/lib/Frontend/CompilerInvocation.cpp
+++ b/lib/Frontend/CompilerInvocation.cpp
@@ -1158,6 +1158,30 @@ static bool ParseIRGenArgs(IRGenOptions &Opts, ArgList &Args,
                      A->getAsString(Args), A->getValue());
     }
   }
+                             
+  // Autolink runtime compatibility libraries, if asked to.
+  if (!Args.hasArg(options::OPT_disable_autolinking_runtime_compatibility)) {
+    Optional<llvm::VersionTuple> runtimeCompatibilityVersion;
+    
+    if (auto versionArg = Args.getLastArg(
+                                  options::OPT_runtime_compatibility_version)) {
+      auto version = StringRef(versionArg->getValue());
+      if (version.equals("none")) {
+        runtimeCompatibilityVersion = None;
+      } else if (version.equals("5.0")) {
+        runtimeCompatibilityVersion = llvm::VersionTuple(5, 0);
+      } else {
+        Diags.diagnose(SourceLoc(), diag::error_invalid_arg_value,
+                       versionArg->getAsString(Args), version);
+      }
+    } else {
+      runtimeCompatibilityVersion =
+                           getSwiftRuntimeCompatibilityVersionForTarget(Triple);
+    }
+      
+    Opts.AutolinkRuntimeCompatibilityLibraryVersion =
+                                                    runtimeCompatibilityVersion;
+  }
 
   return false;
 }
diff --git a/lib/IRGen/GenDecl.cpp b/lib/IRGen/GenDecl.cpp
index 5226ce832bbd3..4de174a745013 100644
--- a/lib/IRGen/GenDecl.cpp
+++ b/lib/IRGen/GenDecl.cpp
@@ -445,6 +445,26 @@ void IRGenModule::emitSourceFile(SourceFile &SF) {
 
   if (ObjCInterop)
     this->addLinkLibrary(LinkLibrary("objc", LibraryKind::Library));
+  
+  // FIXME: It'd be better to have the driver invocation or build system that
+  // executes the linker introduce these compatibility libraries, since at
+  // that point we know whether we're building an executable, which is the only
+  // place where the compatibility libraries take effect. For the benefit of
+  // build systems that build Swift code, but don't use Swift to drive
+  // the linker, we can also use autolinking to pull in the compatibility
+  // libraries. This may however cause the library to get pulled in in
+  // situations where it isn't useful, such as for dylibs, though this is
+  // harmless aside from code size.
+  if (!IRGen.Opts.UseJIT) {
+    if (auto compatibilityVersion
+          = IRGen.Opts.AutolinkRuntimeCompatibilityLibraryVersion) {
+      if (*compatibilityVersion <= llvm::VersionTuple(5, 0)) {
+        this->addLinkLibrary(LinkLibrary("swiftCompatibility50",
+                                         LibraryKind::Library,
+                                         /*forceLoad*/ true));
+      }
+    }
+  }
 }
 
 /// Collect elements of an already-existing global list with the given
diff --git a/stdlib/public/Compatibility50/CMakeLists.txt b/stdlib/public/Compatibility50/CMakeLists.txt
index 970cae529207a..4773fcdabade2 100644
--- a/stdlib/public/Compatibility50/CMakeLists.txt
+++ b/stdlib/public/Compatibility50/CMakeLists.txt
@@ -1,10 +1,12 @@
 set(swift_runtime_compile_flags ${SWIFT_RUNTIME_CORE_CXX_FLAGS})
 set(swift_runtime_linker_flags ${SWIFT_RUNTIME_CORE_LINK_FLAGS})
 
-add_swift_target_library(swiftCompatibility50 TARGET_LIBRARY STATIC
+add_swift_target_library(swiftCompatibility50 TARGET_LIBRARY STATIC INSTALL_WITH_SHARED
   ProtocolConformance.cpp
   Overrides.cpp
   C_COMPILE_FLAGS ${swift_runtime_library_compile_flags}
   LINK_FLAGS ${swift_runtime_linker_flags}
   TARGET_SDKS ${SWIFT_APPLE_PLATFORMS}
-  INSTALL_IN_COMPONENT stdlib)
+  INSTALL_IN_COMPONENT compiler)
+
+
diff --git a/stdlib/public/Compatibility50/Overrides.cpp b/stdlib/public/Compatibility50/Overrides.cpp
index c88ce2bec1cb1..9d7f8eb28e047 100644
--- a/stdlib/public/Compatibility50/Overrides.cpp
+++ b/stdlib/public/Compatibility50/Overrides.cpp
@@ -31,3 +31,8 @@ __attribute__((used, section("__DATA,__swift_hooks"))) = {
   .version = 0,
   .conformsToProtocol = swift50override_conformsToProtocol,
 };
+
+// Allow this library to get force-loaded by autolinking
+__attribute__((weak, visibility("hidden")))
+extern "C"
+char _swift_FORCE_LOAD_$_swiftCompatibility50 = 0;
diff --git a/test/IRGen/autolink-runtime-compatibility.swift b/test/IRGen/autolink-runtime-compatibility.swift
new file mode 100644
index 0000000000000..e6d17fb4c6f02
--- /dev/null
+++ b/test/IRGen/autolink-runtime-compatibility.swift
@@ -0,0 +1,25 @@
+// REQUIRES: OS=macosx
+
+// Doesn't autolink compatibility library because autolinking is disabled
+// RUN: %target-swift-frontend -target x86_64-apple-macosx10.9 -disable-autolinking-runtime-compatibility -emit-ir -parse-stdlib %s | %FileCheck -check-prefix=NO-FORCE-LOAD %s
+// RUN: %target-swift-frontend -runtime-compatibility-version 5.0 -disable-autolinking-runtime-compatibility -emit-ir -parse-stdlib %s | %FileCheck -check-prefix=NO-FORCE-LOAD %s
+
+// Doesn't autolink compatibility library because runtime compatibility library is disabled
+// RUN: %target-swift-frontend -runtime-compatibility-version none -emit-ir -parse-stdlib %s | %FileCheck -check-prefix=NO-FORCE-LOAD %s
+
+// Doesn't autolink compatibility library because target OS doesn't need it
+// RUN: %target-swift-frontend -target x86_64-apple-macosx10.24 -emit-ir -parse-stdlib %s | %FileCheck -check-prefix=NO-FORCE-LOAD %s
+
+// Autolinks because compatibility library was explicitly asked for
+// RUN: %target-swift-frontend -runtime-compatibility-version 5.0 -emit-ir -parse-stdlib %s | %FileCheck -check-prefix=FORCE-LOAD %s
+// RUN: %target-swift-frontend -target x86_64-apple-macosx10.24 -runtime-compatibility-version 5.0 -emit-ir -parse-stdlib %s | %FileCheck -check-prefix=FORCE-LOAD %s
+
+public func foo() {}
+
+// NO-FORCE-LOAD-NOT: FORCE_LOAD
+// NO-FORCE-LOAD-NOT: !{!"-lswiftCompatibility50"}
+
+// FORCE-LOAD: declare {{.*}} @"_swift_FORCE_LOAD_$_swiftCompatibility50"
+
+// FORCE-LOAD-DAG: [[AUTOLINK_SWIFT_COMPAT:![0-9]+]] = !{!"-lswiftCompatibility50"}
+// FORCE-LOAD-DAG: !llvm.linker.options = !{{{.*}}[[AUTOLINK_SWIFT_COMPAT]]{{[,}]}}
diff --git a/test/IRGen/unused.sil b/test/IRGen/unused.sil
index fd260566bcacc..f005364ddb4ee 100644
--- a/test/IRGen/unused.sil
+++ b/test/IRGen/unused.sil
@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -primary-file %s -emit-ir | %FileCheck -check-prefix CHECK -check-prefix NEGATIVE -check-prefix CHECK-%target-object-format %s
+// RUN: %target-swift-frontend -runtime-compatibility-version none -primary-file %s -emit-ir | %FileCheck -check-prefix CHECK -check-prefix NEGATIVE -check-prefix CHECK-%target-object-format %s
 
 // REQUIRES: CPU=x86_64
 
diff --git a/test/Serialization/autolinking.swift b/test/Serialization/autolinking.swift
index 02062d51656ff..5ab7b673f8db2 100644
--- a/test/Serialization/autolinking.swift
+++ b/test/Serialization/autolinking.swift
@@ -1,23 +1,23 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-swift-frontend -emit-module -parse-stdlib -o %t -module-name someModule -module-link-name module %S/../Inputs/empty.swift
-// RUN: %target-swift-frontend -emit-ir -lmagic %s -I %t > %t/out.txt
+// RUN: %target-swift-frontend -runtime-compatibility-version none -emit-ir -lmagic %s -I %t > %t/out.txt
 // RUN: %FileCheck %s < %t/out.txt
 // RUN: %FileCheck -check-prefix=NO-FORCE-LOAD %s < %t/out.txt
 
 // RUN: %empty-directory(%t/someModule.framework/Modules/someModule.swiftmodule)
 // RUN: mv %t/someModule.swiftmodule %t/someModule.framework/Modules/someModule.swiftmodule/%target-swiftmodule-name
-// RUN: %target-swift-frontend -emit-ir -lmagic %s -F %t > %t/framework.txt
+// RUN: %target-swift-frontend -runtime-compatibility-version none -emit-ir -lmagic %s -F %t > %t/framework.txt
 // RUN: %FileCheck -check-prefix=FRAMEWORK %s < %t/framework.txt
 // RUN: %FileCheck -check-prefix=NO-FORCE-LOAD %s < %t/framework.txt
 
 // RUN: %target-swift-frontend -emit-module -parse-stdlib -o %t -module-name someModule -module-link-name module %S/../Inputs/empty.swift -autolink-force-load
-// RUN: %target-swift-frontend -emit-ir -lmagic %s -I %t > %t/force-load.txt
+// RUN: %target-swift-frontend -runtime-compatibility-version none -emit-ir -lmagic %s -I %t > %t/force-load.txt
 // RUN: %FileCheck %s < %t/force-load.txt
 // RUN: %FileCheck -check-prefix FORCE-LOAD-CLIENT -check-prefix FORCE-LOAD-CLIENT-%target-object-format %s < %t/force-load.txt
 
-// RUN: %target-swift-frontend -emit-ir -parse-stdlib -module-name someModule -module-link-name module %S/../Inputs/empty.swift | %FileCheck --check-prefix=NO-FORCE-LOAD %s
-// RUN: %target-swift-frontend -emit-ir -parse-stdlib -module-name someModule -module-link-name module %S/../Inputs/empty.swift -autolink-force-load | %FileCheck --check-prefix=FORCE-LOAD %s
-// RUN: %target-swift-frontend -emit-ir -parse-stdlib -module-name someModule -module-link-name 0module %S/../Inputs/empty.swift -autolink-force-load | %FileCheck --check-prefix=FORCE-LOAD-HEX %s
+// RUN: %target-swift-frontend -runtime-compatibility-version none -emit-ir -parse-stdlib -module-name someModule -module-link-name module %S/../Inputs/empty.swift | %FileCheck --check-prefix=NO-FORCE-LOAD %s
+// RUN: %target-swift-frontend -runtime-compatibility-version none -emit-ir -parse-stdlib -module-name someModule -module-link-name module %S/../Inputs/empty.swift -autolink-force-load | %FileCheck --check-prefix=FORCE-LOAD %s
+// RUN: %target-swift-frontend -runtime-compatibility-version none -emit-ir -parse-stdlib -module-name someModule -module-link-name 0module %S/../Inputs/empty.swift -autolink-force-load | %FileCheck --check-prefix=FORCE-LOAD-HEX %s
 
 // Linux uses a different autolinking mechanism, based on
 // swift-autolink-extract. This file tests the Darwin mechanism.