Store Result* pointer instead of index

ConflictSet.cpp

@@ -4094,13 +4094,34 @@ namespace interleaved_insert {
 
 typedef PRESERVE_NONE void (*Continuation)(struct Job *, struct Context *);
 
+struct Result {
+  Result() = default;
+  Result(Node *insertionPoint, TrivialSpan remaining)
+      : insertionPoint(insertionPoint), remaining(remaining),
+        endInsertionPoint(nullptr) {}
+  Result(Node *insertionPoint, TrivialSpan remaining, Node *endInsertionPoint,
+         TrivialSpan endRemaining)
+      : insertionPoint(insertionPoint), remaining(remaining),
+        endInsertionPoint(endInsertionPoint), endRemaining(endRemaining) {}
+
+  Node *insertionPoint;
+  TrivialSpan remaining;
+
+  Node *endInsertionPoint;  // Range write only
+  TrivialSpan endRemaining; // Range write only
+
+  Result *nextRangeWrite; // Linked list to skip over point writes in phase 3.
+                          // Populated in phase 2
+};
+static_assert(std::is_trivial_v<Result>);
+
 // State relevant to an individual insertion
 struct Job {
   TrivialSpan remaining;
   Node *n;
   TaggedNodePointer child;
   int childIndex;
-  int index;
+  Result *result;
   TrivialSpan begin;   // Range write only
   TrivialSpan end;     // Range write only
   Node *endNode;       // Range write only
@@ -4165,30 +4186,6 @@ struct Job {
   }
 };
 
-// Result of an insertion.  The search path of insertionPoint + remaining == the
-// original key, and there is existing node in the tree further along the search
-// path of the original key
-struct Result {
-  Result() = default;
-  Result(Node *insertionPoint, TrivialSpan remaining)
-      : insertionPoint(insertionPoint), remaining(remaining),
-        endInsertionPoint(nullptr) {}
-  Result(Node *insertionPoint, TrivialSpan remaining, Node *endInsertionPoint,
-         TrivialSpan endRemaining)
-      : insertionPoint(insertionPoint), remaining(remaining),
-        endInsertionPoint(endInsertionPoint), endRemaining(endRemaining) {}
-
-  Node *insertionPoint;
-  TrivialSpan remaining;
-
-  Node *endInsertionPoint;  // Range write only
-  TrivialSpan endRemaining; // Range write only
-
-  Result *nextRangeWrite; // Linked list to skip over point writes in phase 3.
-                          // Populated in phase 2
-};
-static_assert(std::is_trivial_v<Result>);
-
 // State relevant to every insertion
 struct Context {
   int count;
@@ -4250,7 +4247,7 @@ void pointIter(Job *job, Context *context) {
     int partialKeyIndex =
         longestCommonPrefix(child->partialKey(), key.data(), commonLen);
     if (partialKeyIndex < child->partialKeyLen) {
-      context->results[job->index] = {job->n, job->remaining};
+      *job->result = {job->n, job->remaining};
       MUSTTAIL return complete(job, context);
     }
   }
@@ -4271,12 +4268,12 @@ void pointIter(Job *job, Context *context) {
   }
 
   if (job->remaining.size() == 0) [[unlikely]] {
-    context->results[job->index] = {job->n, job->remaining};
+    *job->result = {job->n, job->remaining};
     MUSTTAIL return complete(job, context);
   }
 
   if (!job->getChildAndIndex(child, job->remaining.front())) [[unlikely]] {
-    context->results[job->index] = {job->n, job->remaining};
+    *job->result = {job->n, job->remaining};
     MUSTTAIL return complete(job, context);
   }
 
@@ -4312,7 +4309,7 @@ template <class NodeT> void commonPrefixIter(Job *job, Context *context) {
     int prefixLen = job->commonPrefixLen - job->remaining.size();
     assert(prefixLen >= 0);
     assert(job->n != nullptr);
-    context->results[job->index] = {
+    *job->result = {
         job->n,
         job->begin.subspan(prefixLen, job->begin.size() - prefixLen),
         job->n,
@@ -4366,13 +4363,13 @@ template <class NodeT> void endIter(Job *job, Context *context) {
   TaggedNodePointer *child =
       getChildUpdatingMaxVersion(endNode, job->end, context->writeVersion);
   if (child == nullptr) [[unlikely]] {
-    context->results[job->index] = {job->n, job->begin, job->endNode, job->end};
+    *job->result = {job->n, job->begin, job->endNode, job->end};
     assert(job->endNode != nullptr);
     MUSTTAIL return complete(job, context);
   }
   job->endNode = *child;
   if (job->remaining.size() == 0) [[unlikely]] {
-    context->results[job->index] = {job->n, job->begin, job->endNode, job->end};
+    *job->result = {job->n, job->begin, job->endNode, job->end};
     assert(job->endNode != nullptr);
     MUSTTAIL return complete(job, context);
   }
@@ -4383,7 +4380,7 @@ template <class NodeT> void endIter(Job *job, Context *context) {
 }
 
 void Job::init(Context *context, int index) {
-  this->index = index;
+  result = context->results + index;
   n = context->root;
 
   if (context->writes[index].end.len == 0) {
@@ -4962,9 +4959,7 @@ struct __attribute__((visibility("hidden"))) ConflictSet::Impl {
     // Phase 1: Search for insertion points concurrently, without modifying the
     // structure of the tree.
 
-    if (count == 0) {
-      return;
-    }
+    assert(count > 1);
 
     constexpr int kStackResultMax = 100;
     interleaved_insert::Result stackResults[kStackResultMax];