diff --git a/Modules/Platform/Windows-MSVC.cmake b/Modules/Platform/Windows-MSVC.cmake
index 1920a7c61..6c254ede4 100644
--- a/Modules/Platform/Windows-MSVC.cmake
+++ b/Modules/Platform/Windows-MSVC.cmake
@@ -305,7 +305,7 @@ macro(__windows_compiler_msvc lang)
     set(CMAKE_${lang}_FLAGS_DEBUG_INIT "-D_DEBUG /MDd -gline-tables-only -fno-inline -O0 ${_RTC1}")
     set(CMAKE_${lang}_FLAGS_RELEASE_INIT "/MD -O2 -DNDEBUG")
     set(CMAKE_${lang}_FLAGS_RELWITHDEBINFO_INIT "/MD -gline-tables-only -O2 -fno-inline -DNDEBUG")
-    set(CMAKE_${lang}_FLAGS_MINSIZEREL_INIT "/MD -Os -DNDEBUG")
+    set(CMAKE_${lang}_FLAGS_MINSIZEREL_INIT "/MD -DNDEBUG") # TODO: Add '-Os' once VS generator maps it properly for Clang
   else()
     set(CMAKE_${lang}_FLAGS_INIT "${_PLATFORM_DEFINES}${_PLATFORM_DEFINES_${lang}} /D_WINDOWS /W3${_FLAGS_${lang}}")
     set(CMAKE_${lang}_FLAGS_DEBUG_INIT "/D_DEBUG /MDd /Zi /Ob0 /Od ${_RTC1}")
diff --git a/Source/cmVS14CLFlagTable.h b/Source/cmVS14CLFlagTable.h
index 4243f30d1..5812e79e8 100644
--- a/Source/cmVS14CLFlagTable.h
+++ b/Source/cmVS14CLFlagTable.h
@@ -16,7 +16,6 @@ static cmVS7FlagTable cmVS14CLFlagTable[] = {
 
   { "Optimization", "", "Custom", "Custom", 0 },
   { "Optimization", "Od", "Disabled", "Disabled", 0 },
-  { "Optimization", "Os", "Minimize Size", "MinSize", 0 },
   { "Optimization", "O1", "Minimize Size", "MinSpace", 0 },
   { "Optimization", "O2", "Maximize Speed", "MaxSpeed", 0 },
   { "Optimization", "Ox", "Full Optimization", "Full", 0 },