[PATCH] D53260: [ADT] Fix a bug in DenseSet's initializer_list constructor.

[Lang Hames via Phabricator via llvm-commits]

lhames created this revision.
lhames added reviewers: chandlerc, dblaikie.
Herald added subscribers: kristina, dexonsmith.

Without this fix, DenseSet crashes with an assertion if constructed with an
initializer_list whose length is not a power of two.


Repository:
  rL LLVM

https://reviews.llvm.org/D53260

Files:
  include/llvm/ADT/DenseSet.h
  unittests/ADT/DenseSetTest.cpp


Index: unittests/ADT/DenseSetTest.cpp
===================================================================
--- unittests/ADT/DenseSetTest.cpp
+++ unittests/ADT/DenseSetTest.cpp
@@ -80,6 +80,12 @@
   EXPECT_EQ(0u, set.count(3));
 }
 
+TYPED_TEST(DenseSetTest, InitializerListWithNonPowerOfTwoLength) {
+  // Make sure the initializer list works even when its length is not a power
+  // of two.
+  TypeParam set({1, 2, 3});
+}
+
 TYPED_TEST(DenseSetTest, ConstIteratorComparison) {
   TypeParam set({1});
   const TypeParam &cset = set;
Index: include/llvm/ADT/DenseSet.h
===================================================================
--- include/llvm/ADT/DenseSet.h
+++ include/llvm/ADT/DenseSet.h
@@ -16,6 +16,7 @@
 
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/DenseMapInfo.h"
+#include "llvm/Support/MathExtras.h"
 #include "llvm/Support/type_traits.h"
 #include <algorithm>
 #include <cstddef>
@@ -67,7 +68,7 @@
   explicit DenseSetImpl(unsigned InitialReserve = 0) : TheMap(InitialReserve) {}
 
   DenseSetImpl(std::initializer_list<ValueT> Elems)
-      : DenseSetImpl(Elems.size()) {
+      : DenseSetImpl(NextPowerOf2(Elems.size())) {
     insert(Elems.begin(), Elems.end());
   }
 


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D53260.169618.patch
Type: text/x-patch
Size: 1202 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20181014/86ed74e3/attachment.bin>