COMPMID-1728 CL: Implement ArgMax/ArgMin

Change-Id: I7eae2e55cc0b0b7bbebb7617299daaca6f75f40c
Reviewed-on: https://review.mlplatform.org/292
Tested-by: Arm Jenkins <bsgcomp@arm.com>
Reviewed-by: Georgios Pinitas <georgios.pinitas@arm.com>
diff --git a/arm_compute/core/Types.h b/arm_compute/core/Types.h
index 5ddd207..7db2f5f 100644
--- a/arm_compute/core/Types.h
+++ b/arm_compute/core/Types.h
@@ -545,9 +545,11 @@
 /** Available reduction operations */
 enum class ReductionOperation
 {
-    SUM_SQUARE, /**< Sum of squares */
-    SUM,        /**< Sum */
-    MEAN_SUM,   /**< Mean of sum */
+    SUM_SQUARE,  /**< Sum of squares */
+    SUM,         /**< Sum */
+    MEAN_SUM,    /**< Mean of sum */
+    ARG_IDX_MAX, /**< Index of the max value */
+    ARG_IDX_MIN  /**< Index of the min value */
 };
 
 /** The normalization type used for the normalization layer */