Index: clang/include/clang/Basic/LangOptions.h
===================================================================
--- clang/include/clang/Basic/LangOptions.h
+++ clang/include/clang/Basic/LangOptions.h
@@ -312,7 +312,7 @@
   }
 
   bool assumeFunctionsAreConvergent() const {
-    return (CUDA && CUDAIsDevice) || OpenCL;
+    return ConvergentFunctions;
   }
 
   /// Return the OpenCL C or C++ version as a VersionTuple.
Index: clang/include/clang/Basic/LangOptions.def
===================================================================
--- clang/include/clang/Basic/LangOptions.def
+++ clang/include/clang/Basic/LangOptions.def
@@ -122,6 +122,7 @@
 LANGOPT(ConstStrings      , 1, 0, "const-qualified string support")
 ENUM_LANGOPT(LaxVectorConversions, LaxVectorConversionKind, 2,
              LaxVectorConversionKind::All, "lax vector conversions")
+LANGOPT(ConvergentFunctions, 1, 1, "Assume convergent functions")
 LANGOPT(AltiVec           , 1, 0, "AltiVec-style vector initializers")
 LANGOPT(ZVector           , 1, 0, "System z vector extensions")
 LANGOPT(Exceptions        , 1, 0, "exception handling")
Index: clang/include/clang/Driver/Options.td
===================================================================
--- clang/include/clang/Driver/Options.td
+++ clang/include/clang/Driver/Options.td
@@ -548,6 +548,9 @@
   MetaVarName<"<directory>">;
 def c : Flag<["-"], "c">, Flags<[DriverOption]>, Group<Action_Group>,
   HelpText<"Only run preprocess, compile, and assemble steps">;
+def fconvergent_functions : Joined<["-"], "fconvergent-functions">, Group<f_Group>, Flags<[CC1Option]>,
+  HelpText<"Assume functions may be convergent">;
+
 def cuda_device_only : Flag<["--"], "cuda-device-only">,
   HelpText<"Compile CUDA code for device only">;
 def cuda_host_only : Flag<["--"], "cuda-host-only">,
Index: clang/lib/Frontend/CompilerInvocation.cpp
===================================================================
--- clang/lib/Frontend/CompilerInvocation.cpp
+++ clang/lib/Frontend/CompilerInvocation.cpp
@@ -2756,6 +2756,9 @@
   Opts.BlocksRuntimeOptional = Args.hasArg(OPT_fblocks_runtime_optional);
   Opts.Coroutines = Opts.CPlusPlus2a || Args.hasArg(OPT_fcoroutines_ts);
 
+  Opts.ConvergentFunctions = Opts.OpenCL || (Opts.CUDA && Opts.CUDAIsDevice) ||
+    Args.hasArg(OPT_fconvergent_functions);
+
   Opts.DoubleSquareBracketAttributes =
       Args.hasFlag(OPT_fdouble_square_bracket_attributes,
                    OPT_fno_double_square_bracket_attributes,
Index: clang/test/CodeGen/convergent-functions.cpp
===================================================================
--- /dev/null
+++ clang/test/CodeGen/convergent-functions.cpp
@@ -0,0 +1,8 @@
+// RUN: %clang_cc1 -triple i386-pc-win32 -emit-llvm -fconvergent-functions -o - < %s | FileCheck -check-prefix=CONVFUNC %s
+// RUN: %clang_cc1 -triple i386-pc-win32 -emit-llvm -o - < %s | FileCheck -check-prefix=NOCONVFUNC %s
+
+// Test that the -fconvergent-functions flag works
+
+// CONVFUNC: attributes #0 = { convergent {{.*}} }
+// NOCONVFUNC-NOT: convergent
+void func() { }
Index: clang/test/CodeGenCUDA/propagate-metadata.cu
===================================================================
--- clang/test/CodeGenCUDA/propagate-metadata.cu
+++ clang/test/CodeGenCUDA/propagate-metadata.cu
@@ -11,7 +11,7 @@
 
 // Build the bitcode library.  This is not built in CUDA mode, otherwise it
 // might have incompatible attributes.  This mirrors how libdevice is built.
-// RUN: %clang_cc1 -x c++ -emit-llvm-bc -ftrapping-math -DLIB \
+// RUN: %clang_cc1 -x c++ -fconvergent-functions -emit-llvm-bc -ftrapping-math -DLIB \
 // RUN:   %s -o %t.bc -triple nvptx-unknown-unknown
 
 // RUN: %clang_cc1 -x cuda %s -emit-llvm -mlink-builtin-bitcode %t.bc -o - \
@@ -53,7 +53,8 @@
 
 // Check the attribute list.
 // CHECK: attributes [[attr]] = {
-// CHECK: "no-trapping-math"="true"
+// CHECK-SAME: convergent
+// CHECK-SAME: "no-trapping-math"="true"
 
 // FTZ-SAME: "nvptx-f32ftz"="true"
 // NOFTZ-NOT: "nvptx-f32ftz"="true"