diff --git a/src/hb-subset-cff-common.hh b/src/hb-subset-cff-common.hh
index 364760626..e20de2204 100644
--- a/src/hb-subset-cff-common.hh
+++ b/src/hb-subset-cff-common.hh
@@ -235,8 +235,7 @@ struct subr_flattener_t
   bool flatten (str_buff_vec_t &flat_charstrings)
   {
     unsigned count = plan->num_output_glyphs ();
-    flat_charstrings.alloc (count, true);
-    if (!flat_charstrings.resize (count))
+    if (!flat_charstrings.resize_exact (count))
       return false;
     for (unsigned int i = 0; i < count; i++)
     {
@@ -271,8 +270,7 @@ struct subr_closures_t
 {
   subr_closures_t (unsigned int fd_count) : global_closure (), local_closures ()
   {
-    local_closures.alloc (fd_count, true);
-    local_closures.resize (fd_count);
+    local_closures.resize_exact (fd_count);
   }
 
   void reset ()
@@ -620,15 +618,12 @@ struct subr_subsetter_t
     if (cff_accelerator) {
       // If we are not dropping hinting then charstrings are not modified so we can
       // just use a reference to the cached copies.
-      cached_charstrings.alloc (plan->num_output_glyphs (), true);
-      cached_charstrings.resize (plan->num_output_glyphs ());
+      cached_charstrings.resize_exact (plan->num_output_glyphs ());
       parsed_global_subrs = &cff_accelerator->parsed_global_subrs;
       parsed_local_subrs = &cff_accelerator->parsed_local_subrs;
     } else {
-      parsed_charstrings.alloc (plan->num_output_glyphs (), true);
-      parsed_charstrings.resize (plan->num_output_glyphs ());
-      parsed_global_subrs_storage.alloc (acc.globalSubrs->count, true);
-      parsed_global_subrs_storage.resize (acc.globalSubrs->count);
+      parsed_charstrings.resize_exact (plan->num_output_glyphs ());
+      parsed_global_subrs_storage.resize_exact (acc.globalSubrs->count);
 
       if (unlikely (!parsed_local_subrs_storage.resize (fd_count))) return false;
 
@@ -740,8 +735,7 @@ struct subr_subsetter_t
 
   bool encode_charstrings (str_buff_vec_t &buffArray) const
   {
-    buffArray.alloc (plan->num_output_glyphs (), true);
-    if (unlikely (!buffArray.resize (plan->num_output_glyphs ())))
+    if (unlikely (!buffArray.resize_exact (plan->num_output_glyphs ())))
       return false;
     for (unsigned int i = 0; i < plan->num_output_glyphs (); i++)
     {
@@ -765,8 +759,7 @@ struct subr_subsetter_t
   {
     unsigned int  count = remap.get_population ();
 
-    buffArray.alloc (count, true);
-    if (unlikely (!buffArray.resize (count)))
+    if (unlikely (!buffArray.resize_exact (count)))
       return false;
     for (unsigned int new_num = 0; new_num < count; new_num++)
     {
diff --git a/src/hb-vector.hh b/src/hb-vector.hh
index 1cb4d8fd6..5a0576fdb 100644
--- a/src/hb-vector.hh
+++ b/src/hb-vector.hh
@@ -401,10 +401,10 @@ struct hb_vector_t
     return true;
   }
 
-  bool resize (int size_, bool initialize = true)
+  bool resize (int size_, bool initialize = true, bool exact = false)
   {
     unsigned int size = size_ < 0 ? 0u : (unsigned int) size_;
-    if (!alloc (size))
+    if (!alloc (size, exact))
       return false;
 
     if (size > length)
@@ -421,6 +421,10 @@ struct hb_vector_t
     length = size;
     return true;
   }
+  bool resize_exact (int size_, bool initialize = true)
+  {
+    return resize (size_, initialize, true);
+  }
 
   Type pop ()
   {