From e7a0022232e5f9e947524c5b3216ed829fc92971 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Tom=C3=A1s?= <47506558+MegaRedHand@users.noreply.github.com>
Date: Mon, 31 Jul 2023 19:24:23 -0300
Subject: [PATCH] perf: remove unneeded bitshift in validated addresses
 insertion (#1208)

* Remove unneeded plus one

* Clean up `validate_*`'s code

* Replace `insert` with `push` in extend

* Change approach

The +1 in resize is used to avoid having to allocate in the case the next push falls outside capacity.
Instead, we use a replace in the place of the insert.

* Update changelog

---------

Co-authored-by: Pedro Fontana <fontana.pedro93@gmail.com>
---
 CHANGELOG.md                  |  2 ++
 vm/src/vm/vm_memory/memory.rs | 29 ++++++++++++++---------------
 2 files changed, 16 insertions(+), 15 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index dbf380cd34..ab33b72c76 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,8 @@
 
 * fix: CLI errors bad formatting and handling
 
+* perf: replace insertion with bit-setting in validated addresses [#1208](https://github.com/lambdaclass/cairo-vm/pull/1208)
+
 * fix: return error when a parsed hint's PC is invalid [#1340](https://github.com/lambdaclass/cairo-vm/pull/1340)
 
 * chore(deps): bump _cairo-lang_ dependencies to v2.1.0-rc2 [#1345](https://github.com/lambdaclass/cairo-vm/pull/1345)
diff --git a/vm/src/vm/vm_memory/memory.rs b/vm/src/vm/vm_memory/memory.rs
index bfe3d3d8dc..098e2480fd 100644
--- a/vm/src/vm/vm_memory/memory.rs
+++ b/vm/src/vm/vm_memory/memory.rs
@@ -75,8 +75,7 @@ impl AddressSet {
             if offset >= self.0[segment].len() {
                 self.0[segment].resize(offset + 1, false);
             }
-
-            self.0[segment].insert(offset, true);
+            self.0[segment].replace(offset, true);
         }
     }
 }
@@ -319,10 +318,8 @@ impl Memory {
             .and_then(|x| self.validation_rules.get(x))
         {
             if !self.validated_addresses.contains(&addr) {
-                {
-                    self.validated_addresses
-                        .extend(rule.0(self, addr)?.as_slice());
-                }
+                self.validated_addresses
+                    .extend(rule.0(self, addr)?.as_slice());
             }
         }
         Ok(())
@@ -331,15 +328,17 @@ impl Memory {
     ///Applies validation_rules to the current memory
     pub fn validate_existing_memory(&mut self) -> Result<(), MemoryError> {
         for (index, rule) in self.validation_rules.iter().enumerate() {
-            if let Some(rule) = rule {
-                if index < self.data.len() {
-                    for offset in 0..self.data[index].len() {
-                        let addr = Relocatable::from((index as isize, offset));
-                        if !self.validated_addresses.contains(&addr) {
-                            self.validated_addresses
-                                .extend(rule.0(self, addr)?.as_slice());
-                        }
-                    }
+            if index >= self.data.len() {
+                continue;
+            }
+            let Some(rule) = rule else {
+                continue;
+            };
+            for offset in 0..self.data[index].len() {
+                let addr = Relocatable::from((index as isize, offset));
+                if !self.validated_addresses.contains(&addr) {
+                    self.validated_addresses
+                        .extend(rule.0(self, addr)?.as_slice());
                 }
             }
         }