Update comments on Group::is_identity impl

Author: Avaneesh-axiom

extensions/ecc/guest/src/edwards.rs

@@ -172,6 +172,16 @@ macro_rules! impl_te_group_ops {
                     *self = self.add_impl(self)
                 }
             }
+
+            // Note: It was found that implementing `is_identity` in group.rs as a default
+            // implementation increases the cycle count by 50% on the ecrecover benchmark. For
+            // this reason, we implement it here instead. We hypothesize that this is due to
+            // compiler optimizations that are not possible when the `is_identity` function is
+            // defined in a different source file.
+            #[inline(always)]
+            fn is_identity(&self) -> bool {
+                self == &<Self as Group>::IDENTITY
+            }
         }
 
         impl core::ops::Add<&$struct_name> for $struct_name {

extensions/ecc/guest/src/weierstrass.rs

@@ -451,11 +451,11 @@ macro_rules! impl_sw_group_ops {
                 self.double_assign_impl::<true>();
             }
 
-            // This implementation is the same as the default implementation in the `Group` trait,
-            // but it was found that overriding the default implementation reduced the cycle count
-            // by 50% on the ecrecover benchmark.
-            // We hypothesize that this is due to compiler optimizations that are not possible when
-            // the `is_identity` function is defined in a different source file.
+            // Note: It was found that implementing `is_identity` in group.rs as a default
+            // implementation increases the cycle count by 50% on the ecrecover benchmark. For
+            // this reason, we implement it here instead. We hypothesize that this is due to
+            // compiler optimizations that are not possible when the `is_identity` function is
+            // defined in a different source file.
             #[inline(always)]
             fn is_identity(&self) -> bool {
                 self == &<Self as Group>::IDENTITY