Parser: Implement extension GL_AMD_gpu_shader_half_float.

- Add built-in types: float16_t, f16vec, f16mat.
- Add support of half float constant: hf, HF.
- Extend built-in floating-point operators: +, -, *, /, ++, --, +=, -=,
  *=, /=, ==, !=, >=, <=, >, <.
- Add support of type conversions: float16_t -> XXX, XXX -> float16_t.
- Add new built-in functions.

glslang/Include/intermediate.h

@@ -119,6 +119,22 @@ enum TOperator {
     EOpConvFloatToUint64,
     EOpConvDoubleToUint64,
     EOpConvInt64ToUint64,
+#ifdef AMD_EXTENSIONS
+    EOpConvBoolToFloat16,
+    EOpConvIntToFloat16,
+    EOpConvUintToFloat16,
+    EOpConvFloatToFloat16,
+    EOpConvDoubleToFloat16,
+    EOpConvInt64ToFloat16,
+    EOpConvUint64ToFloat16,
+    EOpConvFloat16ToBool,
+    EOpConvFloat16ToInt,
+    EOpConvFloat16ToUint,
+    EOpConvFloat16ToFloat,
+    EOpConvFloat16ToDouble,
+    EOpConvFloat16ToInt64,
+    EOpConvFloat16ToUint64,
+#endif
 
     //
     // binary operations
@@ -236,6 +252,10 @@ enum TOperator {
     EOpUnpackInt2x32,
     EOpPackUint2x32,
     EOpUnpackUint2x32,
+#ifdef AMD_EXTENSIONS
+    EOpPackFloat2x16,
+    EOpUnpackFloat2x16,
+#endif
 
     EOpLength,
     EOpDistance,
@@ -396,6 +416,21 @@ enum TOperator {
     EOpConstructDMat4x2,
     EOpConstructDMat4x3,
     EOpConstructDMat4x4,
+#ifdef AMD_EXTENSIONS
+    EOpConstructFloat16,
+    EOpConstructF16Vec2,
+    EOpConstructF16Vec3,
+    EOpConstructF16Vec4,
+    EOpConstructF16Mat2x2,
+    EOpConstructF16Mat2x3,
+    EOpConstructF16Mat2x4,
+    EOpConstructF16Mat3x2,
+    EOpConstructF16Mat3x3,
+    EOpConstructF16Mat3x4,
+    EOpConstructF16Mat4x2,
+    EOpConstructF16Mat4x3,
+    EOpConstructF16Mat4x4,
+#endif
     EOpConstructStruct,
     EOpConstructTextureSampler,
     EOpConstructGuardEnd,