Inline val_at (#3273)

Summary:
Pull Request resolved: #3273

Otherwise, we require LTO for decent performance for this thing in kernels.

Reviewed By: kimishpatel, iseeyuan, manuelcandales

Differential Revision: D56503573

fbshipit-source-id: 186cd570919b38a072a316bd1e3da63f4dcda011

Author: swolchok

kernels/portable/cpu/util/kernel_ops_util.cpp

@@ -46,16 +46,6 @@ bool param_array_is_valid(
 
 } // namespace
 
-int64_t val_at(IntArrayRef array, size_t i, int64_t default_value) {
-  if (array.size() == 1) {
-    return array[0];
-  } else if (array.size() > 1) {
-    return array[i];
-  } else {
-    return default_value;
-  }
-}
-
 bool int_array_all_ge(IntArrayRef array, int64_t val) {
   for (size_t i = 0; i < array.size(); ++i) {
     if (array[i] < val) {

kernels/portable/cpu/util/kernel_ops_util.h

@@ -20,7 +20,15 @@ namespace executor {
  * the first element will be returned regardless of what i is requested to
  * simulate broadcasting.
  */
-int64_t val_at(IntArrayRef array, size_t i, int64_t default_value = 1);
+inline int64_t val_at(IntArrayRef array, size_t i, int64_t default_value = 1) {
+  if (array.size() == 1) {
+    return array[0];
+  } else if (array.size() > 1) {
+    return array[i];
+  } else {
+    return default_value;
+  }
+}
 
 /**
  * Checks that all elements of an IntArray are greater than or equal to `val`.