Replace the using of __expf by __ocml_exp_f32 to work-around the test_softmax_rank4 failure (#1394)

include/ck/tensor_operation/gpu/element/unary_element_wise_operation.hpp

@@ -431,7 +431,7 @@ struct Relu
 // https://paperswithcode.com/method/gelu
 // y = 0.5*x*(1+tanh(sqrt(2/pi)*(x+0.044715*x^3)))
 // host code use higher accuracy "exp" and "div"
-// gpu code use lower accuracy "__expf" and "rcp" function
+// gpu code use lower accuracy "_ocml_exp_f32" and "rcp" function
 struct FastGelu
 {
     template <typename Y, typename X>
@@ -451,7 +451,7 @@ struct FastGelu
         y               = x / (1.f + emu);
     }
 
-    // device code, use lower precision "__expf" and "rcp"
+    // device code, use lower precision "__ocml_exp_f32" and "rcp"
     template <>
     __device__ void operator()<float, float>(float& y, const float& x) const
     {
@@ -459,7 +459,7 @@ struct FastGelu
         const float c1  = -2.0 * 0.035677f;
         const float c2  = -2.0 * 0.797885f;
         const float u   = x * (c1 * x * x + c2);
-        const float emu = __expf(u);
+        const float emu = __ocml_exp_f32(u);
 
         y = x * ck::math::rcp(1.f + emu);
     }

include/ck/utility/math_v2.hpp

@@ -839,7 +839,7 @@ inline __device__ T rcp(T x)
 template <typename T>
 inline __device__ T exp(T x)
 {
-    return ck::type_convert<T>(__expf(ck::type_convert<float>(x)));
+    return ck::type_convert<T>(__ocml_exp_f32(ck::type_convert<float>(x)));
 };
 
 template <>
@@ -851,7 +851,7 @@ inline __device__ half_t exp<half_t>(half_t x)
 template <>
 inline __device__ float exp<float>(float x)
 {
-    return __expf(x);
+    return __ocml_exp_f32(x);
 };
 
 template <>

include/ck_tile/core/numeric/bfloat16.hpp

@@ -331,7 +331,10 @@ bfloat16_t sqrt(bfloat16_t x)
 };
 
 CK_TILE_DEVICE
-bfloat16_t exp(bfloat16_t x) { return static_cast<bfloat16_t>(__expf(static_cast<float>(x))); };
+bfloat16_t exp(bfloat16_t x)
+{
+    return static_cast<bfloat16_t>(__ocml_exp_f32(static_cast<float>(x)));
+};
 
 CK_TILE_DEVICE
 bfloat16_t exp2(bfloat16_t x) { return static_cast<bfloat16_t>(exp2f(static_cast<float>(x))); };

include/ck_tile/core/numeric/float8.hpp

@@ -835,7 +835,7 @@ CK_TILE_DEVICE
 fp8_t sqrt(fp8_t x) { return static_cast<fp8_t>(__builtin_amdgcn_sqrtf(static_cast<float>(x))); };
 
 CK_TILE_DEVICE
-fp8_t exp(fp8_t x) { return static_cast<fp8_t>(__expf(static_cast<float>(x))); };
+fp8_t exp(fp8_t x) { return static_cast<fp8_t>(__ocml_exp_f32(static_cast<float>(x))); };
 
 CK_TILE_DEVICE
 fp8_t exp2(fp8_t x) { return static_cast<fp8_t>(exp2f(static_cast<float>(x))); };
@@ -860,7 +860,7 @@ CK_TILE_DEVICE
 bf8_t sqrt(bf8_t x) { return static_cast<bf8_t>(__builtin_amdgcn_sqrtf(static_cast<float>(x))); };
 
 CK_TILE_DEVICE
-bf8_t exp(bf8_t x) { return static_cast<bf8_t>(__expf(static_cast<float>(x))); };
+bf8_t exp(bf8_t x) { return static_cast<bf8_t>(__ocml_exp_f32(static_cast<float>(x))); };
 
 CK_TILE_DEVICE
 bf8_t exp2(bf8_t x) { return static_cast<bf8_t>(exp2f(static_cast<float>(x))); };

include/ck_tile/core/numeric/half.hpp

@@ -374,7 +374,7 @@ half_t sqrt(half_t x)
 };
 
 CK_TILE_DEVICE
-half_t exp(half_t x) { return static_cast<half_t>(__expf(static_cast<float>(x))); };
+half_t exp(half_t x) { return static_cast<half_t>(__ocml_exp_f32(static_cast<float>(x))); };
 
 CK_TILE_DEVICE
 half_t exp2(half_t x) { return static_cast<half_t>(exp2f(static_cast<float>(x))); };

include/ck_tile/core/numeric/math.hpp

@@ -519,7 +519,7 @@ CK_TILE_DEVICE
 double sqrt(double x) { return __builtin_amdgcn_sqrt(x); };
 
 CK_TILE_DEVICE
-float exp(float x) { return __expf(x); };
+float exp(float x) { return __ocml_exp_f32(x); };
 
 CK_TILE_HOST
 float exp(float x) { return std::expf(x); }