SWDEV-525933 - add constexpr operators for fp16/bf16 (#199)

Author: cjatin

hipamd/include/hip/amd_detail/amd_hip_bf16.h

@@ -123,7 +123,6 @@
 #if defined(__HIPCC_RTC__)
 #define __BF16_HOST_DEVICE__ __BF16_DEVICE__
 #else
-#include <algorithm>
 #include <climits>
 #include <cmath>
 #define __BF16_HOST_DEVICE__ __host__ __BF16_DEVICE__
@@ -215,7 +214,7 @@ struct __attribute__((aligned(2))) __hip_bfloat16 {
   __BF16_HOST_DEVICE__ __hip_bfloat16(const float val) : __x_bf16(static_cast<__bf16>(val)) {}
 
   /*! \brief create __hip_bfloat16 from a __hip_bfloat16_raw */
-  __BF16_HOST_DEVICE__ __hip_bfloat16(const __hip_bfloat16_raw& val) : __x(val.x) {}
+  __BF16_HOST_DEVICE__ constexpr __hip_bfloat16(const __hip_bfloat16_raw& val) : __x(val.x) {}
 
   /*! \brief create __hip_bfloat16 from __bf16 */
   __BF16_HOST_DEVICE__ __hip_bfloat16(const __bf16 val) : __x_bf16(val) {}
@@ -232,7 +231,7 @@ struct __attribute__((aligned(2))) __hip_bfloat16 {
   }
 
   /*! \brief return false if bfloat value is +0.0 or -0.0, returns true otherwise */
-  __BF16_HOST_DEVICE__ operator bool() const { return __x_bf16 != 0.0f; }
+  __BF16_HOST_DEVICE__ constexpr operator bool() const { return __x_bf16 != 0.0f; }
 
   /*! \brief return a casted char from underlying float val */
   __BF16_HOST_DEVICE__ operator char() const { return static_cast<char>(__x_bf16); }
@@ -370,7 +369,7 @@ struct __attribute__((aligned(4))) __hip_bfloat162 {
   __BF16_HOST_DEVICE__ __hip_bfloat162(const __hip_bfloat162& val) : x(val.x), y(val.y) {}
 
   /*! \brief create __hip_bfloat162 from two __hip_bfloat16 */
-  __BF16_HOST_DEVICE__ __hip_bfloat162(const __hip_bfloat16& a, const __hip_bfloat16& b)
+  __BF16_HOST_DEVICE__ constexpr __hip_bfloat162(const __hip_bfloat16& a, const __hip_bfloat16& b)
       : x(a), y(b) {}
 
   /*! \brief create __hip_bfloat162 from vector of __bf16_2 */

hipamd/include/hip/amd_detail/amd_hip_fp16.h

@@ -99,7 +99,7 @@ THE SOFTWARE.
             // CREATORS
             __HOST_DEVICE__
             __half() = default;
-            __HOST_DEVICE__
+            __HOST_DEVICE__ constexpr
             __half(const __half_raw& x) : data{x.data} {}
             #if !defined(__HIP_NO_HALF_CONVERSIONS__)
                 __HOST_DEVICE__
@@ -363,12 +363,9 @@ THE SOFTWARE.
             __half2(const __half2_raw& xx) : data{xx.data} {}
             __HOST_DEVICE__
             __half2(decltype(data) xx) : data{xx} {}
-            __HOST_DEVICE__
+            __HOST_DEVICE__ constexpr
             __half2(const __half& xx, const __half& yy)
-                :
-                data{static_cast<__half_raw>(xx).data,
-                     static_cast<__half_raw>(yy).data}
-            {}
+                : x(xx), y(yy) {}
             __HOST_DEVICE__
             __half2(const __half2&) = default;
             __HOST_DEVICE__