Fix the varying sort comparator in ShaderD3D.

The comparator was actually a <= operator, while sort requires a
strict < operator. This was causing a potential assertion failure.

Bug report from Kerim Borchaev.

BUG=angle:742

Change-Id: I37c2925ab0b85e70ee1b2be3c72c6ddc062e8d28
Reviewed-on: https://chromium-review.googlesource.com/218506
Tested-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Shannon Woods <shannonwoods@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>

2 files changed, 38 insertions, 1 deletions

diff --git a/src/libGLESv2/renderer/d3d/ShaderD3D.cpp b/src/libGLESv2/renderer/d3d/ShaderD3D.cpp
index 57edb290..c472113e 100644
--- a/src/libGLESv2/renderer/d3d/ShaderD3D.cpp
+++ b/src/libGLESv2/renderer/d3d/ShaderD3D.cpp
@@ -348,7 +348,7 @@ bool ShaderD3D::compareVarying(const gl::PackedVarying &x, const gl::PackedVaryi
         return true;
     }
 
-    return gl::VariableSortOrder(x.type) <= gl::VariableSortOrder(y.type);
+    return gl::VariableSortOrder(x.type) < gl::VariableSortOrder(y.type);
 }
 
 unsigned int ShaderD3D::getUniformRegister(const std::string &uniformName) const
diff --git a/tests/angle_tests/GLSLTest.cpp b/tests/angle_tests/GLSLTest.cpp
index 233edb38..b47b3f76 100644
--- a/tests/angle_tests/GLSLTest.cpp
+++ b/tests/angle_tests/GLSLTest.cpp
@@ -226,6 +226,43 @@ TEST_F(GLSLTest, InvariantVaryingOut)
     EXPECT_NE(0u, program);
 }
 
+TEST_F(GLSLTest, FrontFacingAndVarying)
+{
+    const std::string vertexShaderSource = SHADER_SOURCE
+    (
+        attribute vec4 a_position;
+        varying float v_varying;
+        void main()
+        {
+            v_varying = a_position.x;
+            gl_Position = a_position;
+        }
+    );
+
+    const std::string fragmentShaderSource = SHADER_SOURCE
+    (
+        precision mediump float;
+        varying float v_varying;
+        void main()
+        {
+            vec4 c;
+
+            if (gl_FrontFacing)
+            {
+                c = vec4(v_varying, 0, 0, 1.0);
+            }
+            else
+            {
+                c = vec4(0, v_varying, 0, 1.0);
+            }
+            gl_FragColor = c;
+        }
+    );
+
+    GLuint program = CompileProgram(vertexShaderSource, fragmentShaderSource);
+    EXPECT_NE(0u, program);
+}
+
 TEST_F(GLSLTest, InvariantVaryingIn)
 {
     const std::string fragmentShaderSource = SHADER_SOURCE