diff --git a/llvm/utils/TableGen/CodeGenDAGPatterns.cpp b/llvm/utils/TableGen/CodeGenDAGPatterns.cpp
--- a/llvm/utils/TableGen/CodeGenDAGPatterns.cpp
+++ b/llvm/utils/TableGen/CodeGenDAGPatterns.cpp
@@ -68,6 +68,7 @@
 // inference will apply to each mode separately.
 
 TypeSetByHwMode::TypeSetByHwMode(ArrayRef<ValueTypeByHwMode> VTList) {
+  AddrSpaces.reserve(VTList.size());
   for (const ValueTypeByHwMode &VVT : VTList) {
     insert(VVT);
     AddrSpaces.push_back(VVT.PtrAddrSpace);