[llvm] 8456e0c - [ADT] Allow std::next to work on BitVector's set_bits_iterator (#80830)

[via llvm-commits]

Author: Jay Foad
Date: 2024-02-13T11:03:20Z
New Revision: 8456e0c290f759807023924481712767a19464c2

URL: https://github.com/llvm/llvm-project/commit/8456e0c290f759807023924481712767a19464c2
DIFF: https://github.com/llvm/llvm-project/commit/8456e0c290f759807023924481712767a19464c2.diff

LOG: [ADT] Allow std::next to work on BitVector's set_bits_iterator (#80830)

Without this I would hit errors with libstdc++-12 like:

/usr/include/c++/12/bits/stl_iterator_base_funcs.h:230:5: note:
candidate template ignored: substitution failure [with _InputIterator =
llvm::const_set_bits_iterator_impl<llvm::BitVector>]: argument may not
have 'void' type
    next(_InputIterator __x, typename
    ^

Added: 
    

Modified: 
    llvm/include/llvm/ADT/BitVector.h
    llvm/unittests/ADT/BitVectorTest.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/include/llvm/ADT/BitVector.h b/llvm/include/llvm/ADT/BitVector.h
index e0de1afcc94182..0eaa77b6dd81ce 100644
--- a/llvm/include/llvm/ADT/BitVector.h
+++ b/llvm/include/llvm/ADT/BitVector.h
@@ -42,7 +42,7 @@ template <typename BitVectorT> class const_set_bits_iterator_impl {
 
 public:
   using iterator_category = std::forward_iterator_tag;
-  using 
diff erence_type   = void;
+  using 
diff erence_type   = std::ptr
diff _t;
   using value_type        = int;
   using pointer           = value_type*;
   using reference         = value_type&;

diff  --git a/llvm/unittests/ADT/BitVectorTest.cpp b/llvm/unittests/ADT/BitVectorTest.cpp
index e00e11e4655aa0..6a4780c143e548 100644
--- a/llvm/unittests/ADT/BitVectorTest.cpp
+++ b/llvm/unittests/ADT/BitVectorTest.cpp
@@ -1143,6 +1143,9 @@ TYPED_TEST(BitVectorTest, EmptyVectorGetData) {
 }
 
 TYPED_TEST(BitVectorTest, Iterators) {
+  TypeParam Singleton(1, true);
+  EXPECT_EQ(std::next(Singleton.set_bits_begin()), Singleton.set_bits_end());
+
   TypeParam Filled(10, true);
   EXPECT_NE(Filled.set_bits_begin(), Filled.set_bits_end());
   unsigned Counter = 0;