Index: libcxxabi/src/demangle/Utility.h
===================================================================
--- libcxxabi/src/demangle/Utility.h
+++ libcxxabi/src/demangle/Utility.h
@@ -38,10 +38,13 @@
   void grow(size_t N) {
     size_t Need = N + CurrentPosition;
     if (Need > BufferCapacity) {
-      // Avoid many reallocations during startup, with a bit of hysteresis.
-      constexpr size_t MinInitAlloc = 1024;
-      Need = std::max(Need, MinInitAlloc);
-      BufferCapacity = std::max(Need, BufferCapacity * 2);
+      // Reduce the number of reallocations, with a bit of hysteresis. The
+      // number here is chosen so the first allocation will more-than-likely not
+      // allocate more than 1K.
+      Need += 1024 - 32;
+      BufferCapacity *= 2;
+      if (BufferCapacity < Need)
+        BufferCapacity = Need;
       Buffer = static_cast<char *>(std::realloc(Buffer, BufferCapacity));
       if (Buffer == nullptr)
         std::terminate();
Index: llvm/include/llvm/Demangle/Utility.h
===================================================================
--- llvm/include/llvm/Demangle/Utility.h
+++ llvm/include/llvm/Demangle/Utility.h
@@ -17,6 +17,7 @@
 #define DEMANGLE_UTILITY_H
 
 #include "StringView.h"
+#include <algorithm>
 #include <array>
 #include <cstdint>
 #include <cstdlib>
@@ -37,10 +38,13 @@
   void grow(size_t N) {
     size_t Need = N + CurrentPosition;
     if (Need > BufferCapacity) {
-      // Avoid many reallocations during startup, with a bit of hysteresis.
-      constexpr size_t MinInitAlloc = 1024;
-      Need = std::max(Need, MinInitAlloc);
-      BufferCapacity = std::max(Need, BufferCapacity * 2);
+      // Reduce the number of reallocations, with a bit of hysteresis. The
+      // number here is chosen so the first allocation will more-than-likely not
+      // allocate more than 1K.
+      Need += 1024 - 32;
+      BufferCapacity *= 2;
+      if (BufferCapacity < Need)
+        BufferCapacity = Need;
       Buffer = static_cast<char *>(std::realloc(Buffer, BufferCapacity));
       if (Buffer == nullptr)
         std::terminate();