[llvm] Fix C++23 error in {Succ,Pred}Iterator

[victorvianna]

[1] calls insert in an underlying vector and in C++23 that requires the iterators to satisfy stricter constraints [2][3].

[1]

llvm-project/llvm/lib/Analysis/LazyValueInfo.cpp

Line 333 in 67e6a37

llvm::append_range(worklist, successors(ToUpdate));

[2]

llvm-project/libcxx/include/__vector/vector.h

Lines 645 to 649 in 20bcf12

	#if _LIBCPP_STD_VER >= 23
	if constexpr (!forward_iterator<_Iterator>) { // Handles input-only sized ranges for insert_range
	ranges::copy_n(std::move(__first), __n, __position);
	} else
	#endif

[3]

llvm-project/libcxx/include/__algorithm/ranges_copy_n.h

Line 61 in 20bcf12

template <input_iterator _Ip, weakly_incrementable _Op>

[llvmbot]

@llvm/pr-subscribers-llvm-ir

Author: Victor Vianna (victorvianna)

Changes

[1] calls insert in an underlying vector and in C++23 that requires the iterators to satisfy stricter constraints [2][3].

[1]

llvm-project/llvm/lib/Analysis/LazyValueInfo.cpp

Line 333 in 67e6a37

llvm::append_range(worklist, successors(ToUpdate));

[2]

llvm-project/libcxx/include/__vector/vector.h

Lines 645 to 649 in 20bcf12

	#if _LIBCPP_STD_VER >= 23
	if constexpr (!forward_iterator<_Iterator>) { // Handles input-only sized ranges for insert_range
	ranges::copy_n(std::move(__first), __n, __position);
	} else
	#endif

[3]

llvm-project/libcxx/include/__algorithm/ranges_copy_n.h

Line 61 in 20bcf12

template <input_iterator _Ip, weakly_incrementable _Op>

---

Full diff: https://github.com/llvm/llvm-project/pull/163555.diff

1 Files Affected:

• (modified) llvm/include/llvm/IR/CFG.h (+4-3)

diff --git a/llvm/include/llvm/IR/CFG.h b/llvm/include/llvm/IR/CFG.h
index 7c7e988fa9e8f..96d3b2fbb5b0b 100644
--- a/llvm/include/llvm/IR/CFG.h
+++ b/llvm/include/llvm/IR/CFG.h
@@ -42,9 +42,9 @@ template <class Ptr, class USE_iterator> // Predecessor Iterator
 class PredIterator {
 public:
   using iterator_category = std::forward_iterator_tag;
-  using value_type = Ptr;
+  using value_type = Ptr *;
   using difference_type = std::ptrdiff_t;
-  using pointer = Ptr *;
+  using pointer = Ptr **;
   using reference = Ptr *;
 
 protected:
@@ -141,7 +141,8 @@ class SuccIterator
                                   std::random_access_iterator_tag, BlockT, int,
                                   BlockT *, BlockT *> {
 public:
-  using difference_type = int;
+  using value_type = BlockT *;
+  using difference_type = std::ptrdiff_t;
   using pointer = BlockT *;
   using reference = BlockT *;
 

[victorvianna]

@frgossen PTAL