From 9046dc5a8fddfa3367f40617ec689fb86b9c417e Mon Sep 17 00:00:00 2001
From: Andrew Noyes <andrew@weaselab.dev>
Date: Sun, 7 Jul 2024 17:28:45 -0700
Subject: [PATCH] Only switch on type once in checkMaxBetweenExclusive

---
 ConflictSet.cpp | 97 ++++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 76 insertions(+), 21 deletions(-)

diff --git a/ConflictSet.cpp b/ConflictSet.cpp
index 8588061..31b7eb6 100644
--- a/ConflictSet.cpp
+++ b/ConflictSet.cpp
@@ -2001,31 +2001,30 @@ bool checkMaxBetweenExclusive(Node *n, int begin, int end,
 
   assert(!(begin == -1 && end == 256));
 
-  {
-    int c = getChildGeq(n, begin + 1);
-    if (c >= 0 && c < end) {
-      auto *child = getChildExists(n, c);
-      if (child->entryPresent) {
-        if (!(child->entry.rangeVersion <= readVersion)) {
-          return false;
-        };
-      }
-      begin = c;
-    } else {
-      return true;
-    }
-  }
-
-  // [begin, end) is now the half-open interval of children we're interested in.
-  assert(begin < end);
-
   switch (n->getType()) {
-  case Type_Node0: // GCOVR_EXCL_LINE
-    // We would have returned above, after not finding a child
-    __builtin_unreachable(); // GCOVR_EXCL_LINE
+  case Type_Node0:
+    return true;
   case Type_Node3: {
     auto *self = static_cast<Node3 *>(n);
 
+    {
+      int c = begin == 255 ? -1 : getChildGeqSimd(self, begin + 1);
+      if (c >= 0 && c < end) {
+        auto *child = self->children[getNodeIndex(self, c)];
+        if (child->entryPresent) {
+          if (!(child->entry.rangeVersion <= readVersion)) {
+            return false;
+          };
+        }
+        begin = c;
+      } else {
+        return true;
+      }
+      // [begin, end) is now the half-open interval of children we're interested
+      // in.
+      assert(begin < end);
+    }
+
     const unsigned shiftUpperBound = end - begin;
     const unsigned shiftAmount = begin;
     auto inBounds = [&](unsigned c) {
@@ -2045,11 +2044,48 @@ bool checkMaxBetweenExclusive(Node *n, int begin, int end,
   case Type_Node16: {
     auto *self = static_cast<Node16 *>(n);
 
+    {
+      int c = begin == 255 ? -1 : getChildGeqSimd(self, begin + 1);
+      if (c >= 0 && c < end) {
+        auto *child = self->children[getNodeIndex(self, c)];
+        if (child->entryPresent) {
+          if (!(child->entry.rangeVersion <= readVersion)) {
+            return false;
+          };
+        }
+        begin = c;
+      } else {
+        return true;
+      }
+      // [begin, end) is now the half-open interval of children we're interested
+      // in.
+      assert(begin < end);
+    }
+
     return scan16<kAVX512>(self->childMaxVersion, self->index, begin, end,
                            readVersion);
   }
   case Type_Node48: {
     auto *self = static_cast<Node48 *>(n);
+
+    {
+      int c = self->bitSet.firstSetGeq(begin + 1);
+      if (c >= 0 && c < end) {
+        auto *child = self->children[self->index[c]];
+        if (child->entryPresent) {
+          if (!(child->entry.rangeVersion <= readVersion)) {
+            return false;
+          };
+        }
+        begin = c;
+      } else {
+        return true;
+      }
+      // [begin, end) is now the half-open interval of children we're interested
+      // in.
+      assert(begin < end);
+    }
+
     // Check all pages
     static_assert(Node48::kMaxOfMaxPageSize == 16);
     for (int i = 0; i < Node48::kMaxOfMaxTotalPages; ++i) {
@@ -2067,6 +2103,25 @@ bool checkMaxBetweenExclusive(Node *n, int begin, int end,
   case Type_Node256: {
     static_assert(Node256::kMaxOfMaxTotalPages == 16);
     auto *self = static_cast<Node256 *>(n);
+
+    {
+      int c = self->bitSet.firstSetGeq(begin + 1);
+      if (c >= 0 && c < end) {
+        auto *child = self->children[c];
+        if (child->entryPresent) {
+          if (!(child->entry.rangeVersion <= readVersion)) {
+            return false;
+          };
+        }
+        begin = c;
+      } else {
+        return true;
+      }
+      // [begin, end) is now the half-open interval of children we're interested
+      // in.
+      assert(begin < end);
+    }
+
     const int firstPage = begin >> Node256::kMaxOfMaxShift;
     const int lastPage = (end - 1) >> Node256::kMaxOfMaxShift;
     // Check the only page if there's only one