diff --git a/Test/baseResults/vulkan.frag.out b/Test/baseResults/vulkan.frag.out
index 1df2c3eb..0e3057eb 100644
--- a/Test/baseResults/vulkan.frag.out
+++ b/Test/baseResults/vulkan.frag.out
@@ -40,7 +40,8 @@ ERROR: 0:92: 'call argument' : sampler constructor must appear at point of use
 ERROR: 0:93: ',' : sampler constructor must appear at point of use 
 ERROR: 0:94: ':' :  wrong operand types: no operation ':' exists that takes a left-hand operand of type 'temp sampler2D' and a right operand of type 'temp sampler2D' (or there is no acceptable conversion)
 ERROR: 0:94: 'call argument' : sampler constructor must appear at point of use 
-ERROR: 38 compilation errors.  No code generated.
+ERROR: 0:96: 'gl_NumSamples' : undeclared identifier 
+ERROR: 39 compilation errors.  No code generated.
 
 
 ERROR: Linking fragment stage: Only one push_constant block is allowed per stage
diff --git a/Test/vulkan.frag b/Test/vulkan.frag
index fd9106cd..16baf862 100644
--- a/Test/vulkan.frag
+++ b/Test/vulkan.frag
@@ -92,4 +92,6 @@ void callUserTexture()
     userTexture((sampler2D(t2d,s)), vTexCoord);                          // ERROR, not point of use
     userTexture((sampler2D(t2d,s), sampler2D(t2d,s)), vTexCoord);        // ERROR, not point of use
     userTexture(cond ? sampler2D(t2d,s) : sampler2D(t2d,s), vTexCoord);  // ERROR, no ?:, not point of use
+
+    gl_NumSamples;   // ERROR, not for Vulkan
 }
diff --git a/glslang/Include/revision.h b/glslang/Include/revision.h
index f99e69a3..4d968252 100644
--- a/glslang/Include/revision.h
+++ b/glslang/Include/revision.h
@@ -2,5 +2,5 @@
 // For the version, it uses the latest git tag followed by the number of commits.
 // For the date, it uses the current date (when then script is run).
 
-#define GLSLANG_REVISION "Overload400-PrecQual.1726"
+#define GLSLANG_REVISION "Overload400-PrecQual.1727"
 #define GLSLANG_DATE "02-Jan-2017"
diff --git a/glslang/MachineIndependent/Initialize.cpp b/glslang/MachineIndependent/Initialize.cpp
index c8739535..443cd7a3 100644
--- a/glslang/MachineIndependent/Initialize.cpp
+++ b/glslang/MachineIndependent/Initialize.cpp
@@ -3010,14 +3010,18 @@ void TBuiltIns::initialize(int version, EProfile profile, const SpvVersion& spvV
                 "flat in int gl_PrimitiveID;"
                 );
 
-        if (version >= 400)
+        if (version >= 400) {
             stageBuiltins[EShLangFragment].append(
                 "flat in  int  gl_SampleID;"
                 "     in  vec2 gl_SamplePosition;"
                 "flat in  int  gl_SampleMaskIn[];"
                 "     out int  gl_SampleMask[];"
-                "uniform int gl_NumSamples;"
                 );
+            if (spvVersion.spv == 0)
+                stageBuiltins[EShLangFragment].append(
+                    "uniform int gl_NumSamples;"
+                    );
+        }
 
         if (version >= 430)
             stageBuiltins[EShLangFragment].append(
@@ -3074,8 +3078,11 @@ void TBuiltIns::initialize(int version, EProfile profile, const SpvVersion& spvV
                 "      in mediump vec2 gl_SamplePosition;"
                 "flat  in highp    int gl_SampleMaskIn[];"
                 "     out highp    int gl_SampleMask[];"
-                "uniform lowp int gl_NumSamples;"
                 );
+            if (spvVersion.spv == 0)
+                stageBuiltins[EShLangFragment].append(  // GL_OES_sample_variables
+                    "uniform lowp int gl_NumSamples;"
+                    );
         }
         stageBuiltins[EShLangFragment].append(
             "highp float gl_FragDepthEXT;"       // GL_EXT_frag_depth
diff --git a/glslang/MachineIndependent/ParseHelper.cpp b/glslang/MachineIndependent/ParseHelper.cpp
index bf59b81b..a5f4d8dc 100644
--- a/glslang/MachineIndependent/ParseHelper.cpp
+++ b/glslang/MachineIndependent/ParseHelper.cpp
@@ -2502,7 +2502,6 @@ void TParseContext::atomicUintCheck(const TSourceLoc& loc, const TType& type, co
 
 void TParseContext::transparentCheck(const TSourceLoc& loc, const TType& type, const TString& /*identifier*/)
 {
-    // double standard due to gl_NumSamples
     if (parsingBuiltins)
         return;