[ESIMD][NFC] Remove some unused HOST code (#12122)

It is cascade removal of some unused code after removing
esimd/detail/host_util.hpp and removing __ESIMD_EMU_DNS namespace.
Even with this change ESIMD headers still have lots of unused HOST-only
code.

Signed-off-by: Klochkov, Vyacheslav N <[email protected]>

Author: v-klochkov

sycl/include/sycl/ext/intel/esimd/detail/bfloat16_type_traits.hpp

@@ -55,12 +55,7 @@ template <int N> struct vector_conversion_traits<bfloat16, N> {
     // cast from _Float16 to int16_t:
     return sycl::bit_cast<vector_type_t<RawT, N>>(ConvVal);
 #else
-    vector_type_t<RawT, N> Output = 0;
-
-    for (int i = 0; i < N; i++) {
-      Output[i] = sycl::bit_cast<RawT>(static_cast<bfloat16>(Val[i]));
-    }
-    return Output;
+    __ESIMD_UNSUPPORTED_ON_HOST;
 #endif // __SYCL_DEVICE_ONLY__
   }
 
@@ -71,12 +66,7 @@ template <int N> struct vector_conversion_traits<bfloat16, N> {
     RawVecT Bits = sycl::bit_cast<RawVecT>(Val);
     return __esimd_bf_cvt<StdT, vc_be_bfloat16_raw_t, N>(Bits);
 #else
-    vector_type_t<StdT, N> Output;
-
-    for (int i = 0; i < N; i++) {
-      Output[i] = sycl::bit_cast<bfloat16>(Val[i]);
-    }
-    return Output;
+    __ESIMD_UNSUPPORTED_ON_HOST;
 #endif // __SYCL_DEVICE_ONLY__
   }
 };

sycl/include/sycl/ext/intel/esimd/detail/defines_elementary.hpp

@@ -53,7 +53,6 @@
 // Macros for internal use
 #define __ESIMD_NS sycl::ext::intel::esimd
 #define __ESIMD_DNS sycl::ext::intel::esimd::detail
-#define __ESIMD_EMU_DNS sycl::ext::intel::esimd::emu::detail
 #define __ESIMD_ENS sycl::ext::intel::experimental::esimd
 #define __ESIMD_EDNS sycl::ext::intel::experimental::esimd::detail
 #define __ESIMD_XMX_NS sycl::ext::intel::esimd::xmx

sycl/include/sycl/ext/intel/esimd/detail/half_type_traits.hpp

@@ -63,15 +63,7 @@ template <int N> struct vector_conversion_traits<sycl::half, N> {
       ;
 #else
   {
-    vector_type_t<half_raw_type, N> Output = 0;
-
-    for (int i = 0; i < N; i += 1) {
-      // 1. Convert Val[i] to float (x) using c++ static_cast
-      // 2. Convert x to half (using float2half)
-      // 3. Output[i] = half_of(x)
-      Output[i] = ::sycl::detail::float2Half(static_cast<float>(Val[i]));
-    }
-    return Output;
+    __ESIMD_UNSUPPORTED_ON_HOST;
   }
 #endif // __SYCL_DEVICE_ONLY__
 
@@ -82,15 +74,7 @@ template <int N> struct vector_conversion_traits<sycl::half, N> {
       ;
 #else
   {
-    vector_type_t<StdT, N> Output;
-
-    for (int i = 0; i < N; i += 1) {
-      // 1. Convert Val[i] to float y(using half2float)
-      // 2. Convert y to StdT using c++ static_cast
-      // 3. Store in Output[i]
-      Output[i] = static_cast<StdT>(::sycl::detail::half2Float(Val[i]));
-    }
-    return Output;
+    __ESIMD_UNSUPPORTED_ON_HOST;
   }
 #endif // __SYCL_DEVICE_ONLY__
 };
@@ -111,7 +95,7 @@ class WrapperElementTypeProxy {
 
   static ESIMD_INLINE sycl::half bitcast_to_wrapper_scalar(half_raw_type Val) {
 #ifndef __SYCL_DEVICE_ONLY__
-    return sycl::half(::sycl::detail::host_half_impl::half(Val));
+    __ESIMD_UNSUPPORTED_ON_HOST;
 #else
     sycl::half Res;
     Res.Data = Val;