Index: cmake/modules/HandleLLVMOptions.cmake
===================================================================
--- cmake/modules/HandleLLVMOptions.cmake
+++ cmake/modules/HandleLLVMOptions.cmake
@@ -363,6 +363,36 @@
 
   append("/Zc:inline" CMAKE_C_FLAGS CMAKE_CXX_FLAGS)
 
+  if (NOT LLVM_ENABLE_TIMESTAMPS AND CMAKE_CXX_COMPILER_ID MATCHES "Clang")
+    # clang-cl and cl by default produce non-deterministic binaries because
+    # link.exe /incremental requires a timestamp in the .obj file.  clang-cl
+    # has the flag /Brepro to force deterministic binaries, so pass that when
+    # LLVM_ENABLE_TIMESTAMPS is turned off.
+    # This checks CMAKE_CXX_COMPILER_ID in addition to check_cxx_compiler_flag()
+    # because cl.exe does not emit an error on flags it doesn't understand,
+    # letting check_cxx_compiler_flag() claim it understands all flags.
+    check_cxx_compiler_flag("/Brepro" SUPPORTS_BREPRO)
+    append_if(SUPPORTS_BREPRO "/Brepro" CMAKE_C_FLAGS CMAKE_CXX_FLAGS)
+
+    if (SUPPORTS_BREPRO)
+      # Check if /INCREMENTAL is passed to the linker and complain that it
+      # won't work with /Brepro.
+      string(TOUPPER "${CMAKE_EXE_LINKER_FLAGS}" upper_exe_flags)
+      string(TOUPPER "${CMAKE_MODULE_LINKER_FLAGS}" upper_module_flags)
+      string(TOUPPER "${CMAKE_SHARED_LINKER_FLAGS}" upper_shared_flags)
+
+      string(FIND "${upper_exe_flags}" "/INCREMENTAL" exe_index)
+      string(FIND "${upper_module_flags}" "/INCREMENTAL" module_index)
+      string(FIND "${upper_shared_flags}" "/INCREMENTAL" shared_index)
+      
+      if (${exe_index} GREATER -1 OR
+          ${module_index} GREATER -1 OR
+          ${shared_index} GREATER -1)
+        message(FATAL_ERROR "LLVM_ENABLE_TIMESTAMPS not compatible with /INCREMENTAL linking")
+      endif()
+    endif()
+  endif()
+
   # Disable sized deallocation if the flag is supported. MSVC fails to compile
   # the operator new overload in User otherwise.
   check_c_compiler_flag("/WX /Zc:sizedDealloc-" SUPPORTS_SIZED_DEALLOC)
Index: lib/MC/WinCOFFObjectWriter.cpp
===================================================================
--- lib/MC/WinCOFFObjectWriter.cpp
+++ lib/MC/WinCOFFObjectWriter.cpp
@@ -969,9 +969,6 @@
 
   Header.PointerToSymbolTable = offset;
 
-  // FIXME: Remove the #else branch and make the #if branch unconditional once
-  // LLVM's self host configuration is aware of /Brepro.
-#if (ENABLE_TIMESTAMPS == 1)
   // MS LINK expects to be able to use this timestamp to implement their
   // /INCREMENTAL feature.
   if (Asm.isIncrementalLinkerCompatible()) {
@@ -980,12 +977,9 @@
       Now = UINT32_MAX;
     Header.TimeDateStamp = Now;
   } else {
+    // Have deterministic output if /INCREMENTAL isn't needed. Also matches GNU.
     Header.TimeDateStamp = 0;
   }
-#else
-  // We want a deterministic output. It looks like GNU as also writes 0 in here.
-  Header.TimeDateStamp = 0;
-#endif
 
   // Write it all to disk...
   WriteFileHeader(Header);
Index: test/MC/COFF/timestamp.s
===================================================================
--- test/MC/COFF/timestamp.s
+++ test/MC/COFF/timestamp.s
@@ -1,5 +1,4 @@
 // RUN: llvm-mc -filetype=obj -triple i686-pc-win32 -incremental-linker-compatible %s -o - | llvm-readobj -h | FileCheck %s
-// REQUIRES: timestamps
 
 // CHECK: ImageFileHeader {
 // CHECK:   TimeDateStamp:
Index: test/lit.cfg
===================================================================
--- test/lit.cfg
+++ test/lit.cfg
@@ -459,10 +459,6 @@
 if not re.match(r'^x86_64.*-(mingw32|windows-gnu|win32)', config.target_triple):
     config.available_features.add('debug_frame')
 
-# Check if we are embedding timestamps.
-if config.enable_timestamps == '1':
-    config.available_features.add('timestamps')
-
 # Check if we should use gmalloc.
 use_gmalloc_str = lit_config.params.get('use_gmalloc', None)
 if use_gmalloc_str is not None:
Index: test/lit.site.cfg.in
===================================================================
--- test/lit.site.cfg.in
+++ test/lit.site.cfg.in
@@ -36,7 +36,6 @@
 config.have_zlib = "@HAVE_LIBZ@"
 config.have_dia_sdk = @HAVE_DIA_SDK@
 config.enable_ffi = "@LLVM_ENABLE_FFI@"
-config.enable_timestamps = "@ENABLE_TIMESTAMPS@"
 config.test_examples = "@ENABLE_EXAMPLES@"
 
 # Support substitution of the tools_dir with user parameters. This is