From 12c6ed2568ae8406f398f9bbb98eb41b0d1b85d7 Mon Sep 17 00:00:00 2001
From: Andrew Noyes <andrew@weaselab.dev>
Date: Thu, 27 Jun 2024 17:21:41 -0700
Subject: [PATCH] Reorganize to prepare for better vectorized first/last page

---
 ConflictSet.cpp | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/ConflictSet.cpp b/ConflictSet.cpp
index 78f8e2a..d7470e1 100644
--- a/ConflictSet.cpp
+++ b/ConflictSet.cpp
@@ -1820,8 +1820,13 @@ bool checkMaxBetweenExclusive(Node *n, int begin, int end,
   }
   case Type_Node256: {
     auto *self = static_cast<Node256 *>(n);
+    if (end <= 0) {
+      return true;
+    }
+    const int firstPage = begin >> Node256::kMaxOfMaxShift;
+    const int lastPage = (end - 1) >> Node256::kMaxOfMaxShift;
     // Check the first page
-    if (self->maxOfMax[begin >> Node256::kMaxOfMaxShift] > readVersion) {
+    if (self->maxOfMax[firstPage] > readVersion) {
       bool result = true;
       for (int i = 0; i < Node256::kMaxOfMaxPageSize; ++i) {
         int j = (begin & ~(Node256::kMaxOfMaxPageSize - 1)) + i;
@@ -1832,8 +1837,7 @@ bool checkMaxBetweenExclusive(Node *n, int begin, int end,
       }
     }
     // Check the last page
-    if (end >= 1 &&
-        self->maxOfMax[(end - 1) >> Node256::kMaxOfMaxShift] > readVersion) {
+    if (self->maxOfMax[lastPage] > readVersion) {
       bool result = true;
       for (int i = 0; i < Node256::kMaxOfMaxPageSize; ++i) {
         int j = ((end - 1) & ~(Node256::kMaxOfMaxPageSize - 1)) + i;
@@ -1849,10 +1853,10 @@ bool checkMaxBetweenExclusive(Node *n, int begin, int end,
       conflict |= (self->maxOfMax[i] > readVersion) << i;
     }
     // Only keep inner pages
-    const int pageBegin = (begin >> Node256::kMaxOfMaxShift) + 1;
-    const int pageEnd = (end - 1) >> Node256::kMaxOfMaxShift;
-    conflict &= (1 << pageEnd) - 1;
-    conflict >>= pageBegin;
+    const int innerPageBegin = (begin >> Node256::kMaxOfMaxShift) + 1;
+    const int innerPageEnd = (end - 1) >> Node256::kMaxOfMaxShift;
+    conflict &= (1 << innerPageEnd) - 1;
+    conflict >>= innerPageBegin;
     return !conflict;
   }
   default:                   // GCOVR_EXCL_LINE