From aaf0283f6686aab07e497afd839820a826841fad Mon Sep 17 00:00:00 2001
From: Andrew Noyes <andrew@weaselab.dev>
Date: Fri, 23 Feb 2024 12:12:01 -0800
Subject: [PATCH] Prefer getChild to getChildGeq in happy path

Saves instructions according to cachegrind
---
 ConflictSet.cpp | 35 ++++++++++++++++++++---------------
 1 file changed, 20 insertions(+), 15 deletions(-)

diff --git a/ConflictSet.cpp b/ConflictSet.cpp
index b6b910e..9558e43 100644
--- a/ConflictSet.cpp
+++ b/ConflictSet.cpp
@@ -811,8 +811,9 @@ bool checkPointRead(Node *n, const std::span<const uint8_t> key,
       goto downLeftSpine;
     }
 
-    int c = getChildGeq(n, remaining[0]);
-    if (c != remaining[0]) {
+    auto *child = getChild(n, remaining[0]);
+    if (child == nullptr) {
+      int c = getChildGeq(n, remaining[0]);
       if (c >= 0) {
         n = getChildExists(n, c);
         goto downLeftSpine;
@@ -822,7 +823,7 @@ bool checkPointRead(Node *n, const std::span<const uint8_t> key,
       }
     }
 
-    n = getChildExists(n, c);
+    n = child;
     remaining = remaining.subspan(1, remaining.size() - 1);
 
     if (n->partialKeyLen > 0) {
@@ -968,8 +969,9 @@ bool checkRangeStartsWith(Node *n, std::span<const uint8_t> key, int begin,
       return maxBetweenExclusive(n, begin, end) <= readVersion;
     }
 
-    int c = getChildGeq(n, remaining[0]);
-    if (c != remaining[0]) {
+    auto *child = getChild(n, remaining[0]);
+    if (child == nullptr) {
+      int c = getChildGeq(n, remaining[0]);
       if (c >= 0) {
         n = getChildExists(n, c);
         goto downLeftSpine;
@@ -979,7 +981,7 @@ bool checkRangeStartsWith(Node *n, std::span<const uint8_t> key, int begin,
       }
     }
 
-    n = getChildExists(n, c);
+    n = child;
     remaining = remaining.subspan(1, remaining.size() - 1);
 
     if (n->partialKeyLen > 0) {
@@ -1066,8 +1068,9 @@ struct CheckRangeLeftSide {
         }
       }
 
-      int c = getChildGeq(n, remaining[0]);
-      if (c != remaining[0]) {
+      auto *child = getChild(n, remaining[0]);
+      if (child == nullptr) {
+        int c = getChildGeq(n, remaining[0]);
         if (c >= 0) {
           if (searchPathLen < prefixLen) {
             n = getChildExists(n, c);
@@ -1082,7 +1085,7 @@ struct CheckRangeLeftSide {
         }
       }
 
-      n = getChildExists(n, c);
+      n = child;
       remaining = remaining.subspan(1, remaining.size() - 1);
       ++searchPathLen;
 
@@ -1208,8 +1211,9 @@ struct CheckRangeRightSide {
         return true;
       }
 
-      int c = getChildGeq(n, remaining[0]);
-      if (c != remaining[0]) {
+      auto *child = getChild(n, remaining[0]);
+      if (child == nullptr) {
+        int c = getChildGeq(n, remaining[0]);
         if (c >= 0) {
           n = getChildExists(n, c);
           return downLeftSpine();
@@ -1218,7 +1222,7 @@ struct CheckRangeRightSide {
         }
       }
 
-      n = getChildExists(n, c);
+      n = child;
       remaining = remaining.subspan(1, remaining.size() - 1);
       ++searchPathLen;
 
@@ -1585,8 +1589,9 @@ struct FirstGeqStepwise {
         return downLeftSpine();
       }
 
-      int c = getChildGeq(n, remaining[0]);
-      if (c != remaining[0]) {
+      auto *child = getChild(n, remaining[0]);
+      if (child == nullptr) {
+        int c = getChildGeq(n, remaining[0]);
         if (c >= 0) {
           n = getChildExists(n, c);
           return downLeftSpine();
@@ -1596,7 +1601,7 @@ struct FirstGeqStepwise {
         }
       }
 
-      n = getChildExists(n, c);
+      n = child;
       remaining = remaining.subspan(1, remaining.size() - 1);
 
       if (n->partialKeyLen > 0) {