[ExecuTorch] Make optimized op_exp support bf16

Pull Request resolved: pytorch/executorch#5677

needed to unblock UnaryUfuncRealHBToFloatHTest change that should be stacked on this rev.
ghstack-source-id: 245578280
@exported-using-ghexport

Differential Revision: [D63438655](https://our.internmc.facebook.com/intern/diff/D63438655/)

Author: swolchok

kernels/optimized/cpu/op_exp.cpp

@@ -26,9 +26,9 @@ template <
     typename CTYPE_IN,
     typename CTYPE_OUT,
     typename std::enable_if<
-        std::is_same<CTYPE_IN, CTYPE_OUT>::value &&
-            !std::is_same<CTYPE_IN, exec_aten::Half>::value &&
-            !std::is_same<CTYPE_OUT, exec_aten::Half>::value,
+        std::is_same_v<CTYPE_IN, CTYPE_OUT> &&
+            !std::is_same_v<CTYPE_IN, exec_aten::Half> &&
+            !std::is_same_v<CTYPE_OUT, exec_aten::BFloat16>,
         int>::type = 0>
 void exp_data(
     const CTYPE_IN* in_data,
@@ -46,9 +46,11 @@ template <
     typename CTYPE_IN,
     typename CTYPE_OUT,
     typename std::enable_if<
-        !std::is_same<CTYPE_IN, CTYPE_OUT>::value ||
-            std::is_same<CTYPE_IN, exec_aten::Half>::value ||
-            std::is_same<CTYPE_OUT, exec_aten::Half>::value,
+        !std::is_same_v<CTYPE_IN, CTYPE_OUT> ||
+            std::is_same_v<CTYPE_IN, exec_aten::Half> ||
+            std::is_same_v<CTYPE_IN, exec_aten::BFloat16> ||
+            std::is_same_v<CTYPE_OUT, exec_aten::Half> ||
+            std::is_same_v<CTYPE_OUT, exec_aten::BFloat16>,
         int>::type = 0>
 void exp_data(
     const CTYPE_IN* in_data,
@@ -76,13 +78,14 @@ Tensor& opt_exp_out(KernelRuntimeContext& ctx, const Tensor& in, Tensor& out) {
 
   ET_KERNEL_CHECK(ctx, tensor_is_floating_type(out), InvalidArgument, out);
 
-  ET_SWITCH_REALHB_TYPES(in.scalar_type(), ctx, "exp.out", CTYPE_IN, [&] {
-    ET_SWITCH_FLOATH_TYPES(out.scalar_type(), ctx, "exp.out", CTYPE_OUT, [&] {
-      exp_data<CTYPE_IN, CTYPE_OUT>(
-          in.const_data_ptr<CTYPE_IN>(),
-          in.numel(),
-          out.mutable_data_ptr<CTYPE_OUT>());
-    });
+  ET_SWITCH_REALHBBF16_TYPES(in.scalar_type(), ctx, "exp.out", CTYPE_IN, [&] {
+    ET_SWITCH_FLOATHBF16_TYPES(
+        out.scalar_type(), ctx, "exp.out", CTYPE_OUT, [&] {
+          exp_data<CTYPE_IN, CTYPE_OUT>(
+              in.const_data_ptr<CTYPE_IN>(),
+              in.numel(),
+              out.mutable_data_ptr<CTYPE_OUT>());
+        });
   });
 
   return out;