From: Giuseppe Ottaviano <ott@fb.com>
Date: Wed, 25 Nov 2015 21:39:14 +0000 (-0800)
Subject: Skip reallocation in shrink_to_fit for empty fbvector
X-Git-Tag: deprecate-dynamic-initializer~228
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=ac06a3093239f271ec81255ed8ad6c48b85e8f16;p=folly.git

Skip reallocation in shrink_to_fit for empty fbvector

Reviewed By: philippv

Differential Revision: D2696314

fb-gh-sync-id: 105de2d99bb9f5ac82310e37f9302022c103befc
---

diff --git a/folly/FBVector.h b/folly/FBVector.h
index 22d76034..c773a7f9 100644
--- a/folly/FBVector.h
+++ b/folly/FBVector.h
@@ -966,6 +966,12 @@ public:
   }
 
   void shrink_to_fit() noexcept {
+    if (empty()) {
+      // Just skip reallocation.
+      *this = fbvector();
+      return;
+    }
+
     auto const newCapacityBytes = folly::goodMallocSize(size() * sizeof(T));
     auto const newCap = newCapacityBytes / sizeof(T);
     auto const oldCap = capacity();