From 6d8017d07ed88e5ea7063683df3d8d8110da6ba3 Mon Sep 17 00:00:00 2001
From: ToweringTopaz <87142001+ToweringTopaz@users.noreply.github.com>
Date: Tue, 23 Aug 2022 15:38:13 -0500
Subject: [PATCH] Optimize Create2.computeAddress (#3600)

Co-authored-by: Hadrien Croubois <hadrien.croubois@gmail.com>
Co-authored-by: Francisco <frangio.1@gmail.com>
---
 CHANGELOG.md                |  1 +
 contracts/utils/Create2.sol | 29 +++++++++++++++++++++++------
 2 files changed, 24 insertions(+), 6 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index e54573795..e18691c7d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -18,6 +18,7 @@
  * `VestingWallet`: remove unused library `Math.sol`. ([#3605](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3605))
  * `ECDSA`: Remove redundant check on the `v` value. ([#3591](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3591))
  * `VestingWallet`: add `releasable` getters. ([#3580](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3580))
+ * `Create2`: optimize address computation by using assembly instead of `abi.encodePacked`. ([#3600](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3600))
 
 ### Deprecations
 
diff --git a/contracts/utils/Create2.sol b/contracts/utils/Create2.sol
index b1e4ee15c..80acc3e2f 100644
--- a/contracts/utils/Create2.sol
+++ b/contracts/utils/Create2.sol
@@ -31,8 +31,7 @@ library Create2 {
         uint256 amount,
         bytes32 salt,
         bytes memory bytecode
-    ) internal returns (address) {
-        address addr;
+    ) internal returns (address addr) {
         require(address(this).balance >= amount, "Create2: insufficient balance");
         require(bytecode.length != 0, "Create2: bytecode length is zero");
         /// @solidity memory-safe-assembly
@@ -40,7 +39,6 @@ library Create2 {
             addr := create2(amount, add(bytecode, 0x20), mload(bytecode), salt)
         }
         require(addr != address(0), "Create2: Failed on deploy");
-        return addr;
     }
 
     /**
@@ -59,8 +57,27 @@ library Create2 {
         bytes32 salt,
         bytes32 bytecodeHash,
         address deployer
-    ) internal pure returns (address) {
-        bytes32 _data = keccak256(abi.encodePacked(bytes1(0xff), deployer, salt, bytecodeHash));
-        return address(uint160(uint256(_data)));
+    ) internal pure returns (address addr) {
+        /// @solidity memory-safe-assembly
+        assembly {
+            let ptr := mload(0x40) // Get free memory pointer
+
+            // |                   | ↓ ptr ...  ↓ ptr + 0x0B (start) ...  ↓ ptr + 0x20 ...  ↓ ptr + 0x40 ...   |
+            // |-------------------|---------------------------------------------------------------------------|
+            // | bytecodeHash      |                                                        CCCCCCCCCCCCC...CC |
+            // | salt              |                                      BBBBBBBBBBBBB...BB                   |
+            // | deployer          | 000000...0000AAAAAAAAAAAAAAAAAAA...AA                                     |
+            // | 0xFF              |            FF                                                             |
+            // |-------------------|---------------------------------------------------------------------------|
+            // | memory            | 000000...00FFAAAAAAAAAAAAAAAAAAA...AABBBBBBBBBBBBB...BBCCCCCCCCCCCCC...CC |
+            // | keccak(start, 85) |            ↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑ |
+
+            mstore(add(ptr, 0x40), bytecodeHash)
+            mstore(add(ptr, 0x20), salt)
+            mstore(ptr, deployer) // Right-aligned with 12 preceding garbage bytes
+            let start := add(ptr, 0x0b) // The hashed data starts at the final garbage byte which we will set to 0xff
+            mstore8(start, 0xff)
+            addr := keccak256(start, 85)
+        }
     }
 }