Works with GCC

src/include/migraphx/migraphx_float8.hpp

@@ -22,12 +22,13 @@
 
 #ifndef MIGRAPHX_GUARD_RTGLIB_FLOAT8_HPP
 #define MIGRAPHX_GUARD_RTGLIB_FLOAT8_HPP
-
+#if defined(__clang__) and !defined(__GNUC__)
 #pragma clang diagnostic push
 #pragma clang diagnostic ignored "-Wold-style-cast"
 #pragma clang diagnostic ignored "-Wfloat-equal"
 #pragma clang diagnostic ignored "-Wmacro-redefined"
 #pragma clang diagnostic ignored "-Wc++20-extensions"
+#endif
 
 #if(defined(__HIP_PLATFORM_HCC__) || defined(__HIP_PLATFORM_AMD__))
 // need to include hip_runtime.h otherwise it complains about __host__ and __device__
@@ -428,6 +429,7 @@ inline std::ostream& operator<<(std::ostream& os, const migraphx_fp8::hip_f8<T>&
         return U(static_cast<float>(lhs) binary_op static_cast<float>(rhs));    \
     }
 
+// TODO: these should return floats
 MIGRAPHX_FP8_BINARY_OP(*, migraphx_fp8::hip_f8<T>)
 MIGRAPHX_FP8_BINARY_OP(-, migraphx_fp8::hip_f8<T>)
 MIGRAPHX_FP8_BINARY_OP(/, migraphx_fp8::hip_f8<T>)
@@ -602,5 +604,7 @@ struct common_type<migraphx_fp8::fp8e4m3fnuz, migraphx_fp8::fp8e4m3fnuz>
 
 } // namespace std
 // =================================================================================================
+#if defined(__clang__) and !defined(__GNUC__)
 #pragma clang diagnostic pop
+#endif
 #endif // MIGRAPHX_GUARD_RTGLIB_FLOAT8_HPP

src/include/migraphx/migraphx_hip_f8_impl.hpp

@@ -22,11 +22,12 @@
 
 #ifndef MIGRAPHX_HIP_FP8_IMPL_HPP
 #define MIGRAPHX_HIP_FP8_IMPL_HPP
-
+#if !defined(__GNUC__)
 #pragma clang diagnostic push
-#pragma clang diagnostic ignored "-Wundefined-reinterpret-cast"
 #pragma clang diagnostic ignored "-Wreserved-identifier"
+#endif
 
+#define CONST_FOLD(x) (__builtin_constant_p(x) ? (x) : (x))
 namespace migraphx_hip_f8_impl {
 namespace detail {
 template <bool B, class T, class F>
@@ -55,17 +56,25 @@ MIGRAPHX_HIP_HOST_DEVICE constexpr uint8_t cast_to_f8(T _x, bool stoch, uint32_t
     static_assert(wm + we == 7, "wm+we==7");
 
     const int mfmt = (sizeof(T) == 4) ? 23 : 10;
-    uint32_t x;
-    if(sizeof(T) == 4)
-        x = reinterpret_cast<uint32_t&>(_x);
+    typename detail::conditional<sizeof(T) == 2, uint16_t, uint32_t>::type x;
+
+#if defined(__GNUC__) and !defined(__clang__)
+    if constexpr(sizeof(T) == 4)
+        x = CONST_FOLD(*reinterpret_cast<uint32_t*>(&_x));
+    else
+        x = CONST_FOLD(*reinterpret_cast<uint16_t*>(&_x));
+#else
+    if constexpr(sizeof(T) == 4)
+        x = __builtin_bit_cast(uint32_t, _x);
     else
-        x = reinterpret_cast<uint16_t&>(_x);
+        x = __builtin_bit_cast(uint16_t, _x);
+#endif
 
     uint32_t head, mantissa;
     int exponent, bias;
     uint32_t sign;
 
-    if(sizeof(T) == 4)
+    if constexpr(sizeof(T) == 4)
     {
         head     = x & 0xFF800000;
         mantissa = x & 0x7FFFFF;
@@ -233,14 +242,22 @@ MIGRAPHX_HIP_HOST_DEVICE constexpr T cast_from_f8(uint8_t x)
     constexpr int wmo = 23;
 
     T fInf, fNegInf, fNaN, fNeg0;
-    const uint32_t ifInf    = 0x7F800000;
-    const uint32_t ifNegInf = 0xFF800000;
-    const uint32_t ifNaN    = 0x7F800001;
-    const uint32_t ifNeg0   = 0x80000000;
-    fInf                    = reinterpret_cast<const float&>(ifInf);
-    fNegInf                 = reinterpret_cast<const float&>(ifNegInf);
-    fNaN                    = reinterpret_cast<const float&>(ifNaN);
-    fNeg0                   = reinterpret_cast<const float&>(ifNeg0);
+    uint32_t ifInf    = 0x7F800000;
+    uint32_t ifNegInf = 0xFF800000;
+    uint32_t ifNaN    = 0x7F800001;
+    uint32_t ifNeg0   = 0x80000000;
+#if defined(__GNUC__) and !defined(__clang__)
+    fInf    = CONST_FOLD(*(reinterpret_cast<float*>(&ifInf)));
+    fNegInf = CONST_FOLD(*(reinterpret_cast<float*>(&ifNegInf)));
+    fNaN    = CONST_FOLD(*(reinterpret_cast<float*>(&ifNaN)));
+    fNeg0   = CONST_FOLD(*(reinterpret_cast<float*>(&ifNeg0)));
+#else
+    // TODO: need to change T for half but right now it would never be called with half
+    fInf    = __builtin_bit_cast(float, ifInf);
+    fNegInf = __builtin_bit_cast(float, ifNegInf);
+    fNaN    = __builtin_bit_cast(float, ifNaN);
+    fNeg0   = __builtin_bit_cast(float, ifNeg0);
+#endif
 
     if(x == 0)
         return 0;
@@ -288,9 +305,15 @@ MIGRAPHX_HIP_HOST_DEVICE constexpr T cast_from_f8(uint8_t x)
         retval = (sign << 15) | (exponent << 10) | mantissa;
     else
         retval = (sign << 31) | (exponent << 23) | mantissa;
-    return reinterpret_cast<const T&>(retval);
+#if defined(__GNUC__) and !defined(__clang__)
+    return CONST_FOLD(*reinterpret_cast<T*>(&retval));
+#else
+    return __builtin_bit_cast(T, retval);
+#endif
 }
 
 } // namespace migraphx_hip_f8_impl
+#if !defined(__GNUC__)
 #pragma clang diagnostic pop
+#endif
 #endif // MIGRAPHX_HIP_FP8_IMPL_HPP