From 4cdf6deb504a3d511623497433f27ccb6a8cb345 Mon Sep 17 00:00:00 2001
From: Andrew Noyes <andrew@weaselab.dev>
Date: Thu, 1 Aug 2024 10:28:50 -0700
Subject: [PATCH] Remove a branch in happy path in addWrites

---
 ConflictSet.cpp | 29 +++++++++++++++++------------
 1 file changed, 17 insertions(+), 12 deletions(-)

diff --git a/ConflictSet.cpp b/ConflictSet.cpp
index 9d138e4..51780e6 100644
--- a/ConflictSet.cpp
+++ b/ConflictSet.cpp
@@ -3174,19 +3174,24 @@ struct __attribute__((visibility("hidden"))) ConflictSet::Impl {
 
     assert(writeVersion >= newestVersionFullPrecision);
 
-    if (writeVersion > newestVersionFullPrecision + kNominalVersionWindow) {
-      destroyTree(root);
-      init(writeVersion - kNominalVersionWindow);
-    }
+    if (oldestExtantVersion < writeVersion - kMaxCorrectVersionWindow)
+        [[unlikely]] {
+      if (writeVersion > newestVersionFullPrecision + kNominalVersionWindow) {
+        destroyTree(root);
+        init(writeVersion - kNominalVersionWindow);
+      }
 
-    newestVersionFullPrecision = writeVersion;
-    newest_version.set(newestVersionFullPrecision);
-    setOldestVersion(
-        std::max(oldestVersionFullPrecision,
-                 newestVersionFullPrecision - kNominalVersionWindow));
-    while (oldestExtantVersion <
-           newestVersionFullPrecision - kMaxCorrectVersionWindow) {
-      gcScanStep(1000);
+      newestVersionFullPrecision = writeVersion;
+      newest_version.set(newestVersionFullPrecision);
+      setOldestVersion(newestVersionFullPrecision - kNominalVersionWindow);
+      while (oldestExtantVersion <
+             newestVersionFullPrecision - kMaxCorrectVersionWindow) {
+        gcScanStep(1000);
+      }
+    } else {
+      newestVersionFullPrecision = writeVersion;
+      newest_version.set(newestVersionFullPrecision);
+      setOldestVersion(newestVersionFullPrecision - kNominalVersionWindow);
     }
 
     for (int i = 0; i < count; ++i) {