# UNDF: UNDF-2026-000001042
# UNDF: UNDF-2026-XXXXXXXXX
--- a/Source/Core/Core/PowerPC/BreakPoints.h
+++ b/Source/Core/Core/PowerPC/BreakPoints.h
@@ -7,6 +7,7 @@
 #include <cstddef>
 #include <optional>
 #include <string>
+#include <unordered_map>
 #include <vector>

 #include "Common/BitSet.h"
@@ -60,11 +61,18 @@ public:
   bool Remove(u32 address);
   void Clear();
   void ClearTemporary();
+
+  // Rebuild the O(1) address index. Called after any mutation.
+  void RebuildIndex();

 private:
   TBreakPoints m_breakpoints;
   std::optional<TBreakPoint> m_temp_breakpoint;
   Core::System& m_system;
   bool m_breaking_enabled = true;
+
+  // Address -> index into m_breakpoints for O(1) lookup.
+  // Invalidated and rebuilt on every Add/Remove/Clear.
+  std::unordered_map<u32, std::size_t> m_bp_index;
 };
--- a/Source/Core/Core/PowerPC/BreakPoints.cpp
+++ b/Source/Core/Core/PowerPC/BreakPoints.cpp
@@ -52,10 +52,17 @@ const TBreakPoint* BreakPoints::GetBreakpoint(u32 address) const
   return GetRegularBreakpoint(address);
 }

+void BreakPoints::RebuildIndex()
+{
+  m_bp_index.clear();
+  m_bp_index.reserve(m_breakpoints.size());
+  for (std::size_t i = 0; i < m_breakpoints.size(); ++i)
+    m_bp_index[m_breakpoints[i].address] = i;
+}
+
 const TBreakPoint* BreakPoints::GetRegularBreakpoint(u32 address) const
 {
-  auto bp = std::ranges::find(m_breakpoints, address, &TBreakPoint::address);
-
-  if (bp == m_breakpoints.end())
+  // O(1) hash lookup instead of O(N) linear scan over m_breakpoints.
+  auto it = m_bp_index.find(address);
+  if (it == m_bp_index.end())
     return nullptr;

-  return &*bp;
+  return &m_breakpoints[it->second];
 }

@@ -115,7 +122,9 @@ void BreakPoints::Add(TBreakPoint bp)
   if (IsAddressBreakPoint(bp.address))
     return;

   m_system.GetJitInterface().InvalidateICache(bp.address, 4, true);
-
   m_breakpoints.emplace_back(std::move(bp));
+  RebuildIndex();
 }

@@ -133,6 +142,7 @@ void BreakPoints::Add(u32 address, bool break_on_hit, bool log_on_hit,
   {
     bp.is_enabled = iter->is_enabled;
     *iter = std::move(bp);
+    RebuildIndex();
   }
   else
   {
     m_breakpoints.emplace_back(std::move(bp));
+    RebuildIndex();
   }

@@ -181,7 +192,9 @@ bool BreakPoints::Remove(u32 address)
   if (iter == m_breakpoints.cend())
     return false;

   m_breakpoints.erase(iter);
+  RebuildIndex();
   m_system.GetJitInterface().InvalidateICache(address, 4, true);

   return true;
 }

@@ -192,6 +205,7 @@ void BreakPoints::Clear()
     m_system.GetJitInterface().InvalidateICache(bp.address, 4, true);
   }

   m_breakpoints.clear();
+  m_bp_index.clear();
   ClearTemporary();
 }