From f84aa88202807f811723ff1c29e47eb389eb3294 Mon Sep 17 00:00:00 2001
From: Andrew Noyes <andrew@weaselab.dev>
Date: Fri, 23 Feb 2024 13:31:05 -0800
Subject: [PATCH] Copy old node to new more efficiently

Presumably it's generating good code for the memcpy with a static size,
and hopefully also eliminating redundant stores
---
 ConflictSet.cpp | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/ConflictSet.cpp b/ConflictSet.cpp
index 4a7aac8..e29094a 100644
--- a/ConflictSet.cpp
+++ b/ConflictSet.cpp
@@ -1419,12 +1419,13 @@ bool checkRangeRead(Node *n, std::span<const uint8_t> begin,
         longestCommonPrefixPartialKey(self->partialKey, key.data(), commonLen);
     if (partialKeyIndex < self->partialKeyLen) {
       auto *old = self;
+
       self = allocators->node4.allocate();
-      self->maxVersion = old->maxVersion;
+
+      memcpy((void *)self, old, offsetof(Node, type));
       self->partialKeyLen = partialKeyIndex;
-      self->parent = old->parent;
-      self->parentsIndex = old->parentsIndex;
-      memcpy(self->partialKey, old->partialKey, partialKeyIndex);
+      self->entryPresent = false;
+      self->numChildren = 0;
 
       getOrCreateChild(self, old->partialKey[partialKeyIndex], allocators) =
           old;