1 files changed, 45 insertions, 0 deletions
diff --git a/include/llvm/IR/BasicBlock.h b/include/llvm/IR/BasicBlock.h
index c917b1f2cada..235cb57cfd09 100644
--- a/include/llvm/IR/BasicBlock.h
+++ b/include/llvm/IR/BasicBlock.h
@@ -33,6 +33,7 @@ class Function;
 class LandingPadInst;
 class LLVMContext;
 class Module;
+class PHINode;
 class TerminatorInst;
 class ValueSymbolTable;
 
@@ -261,6 +262,50 @@ public:
   inline const Instruction       &back() const { return InstList.back();  }
   inline       Instruction       &back()       { return InstList.back();  }
 
+  /// Iterator to walk just the phi nodes in the basic block.
+  template <typename PHINodeT = PHINode, typename BBIteratorT = iterator>
+  class phi_iterator_impl
+      : public iterator_facade_base<phi_iterator_impl<PHINodeT, BBIteratorT>,
+                                    std::forward_iterator_tag, PHINodeT> {
+    friend BasicBlock;
+
+    PHINodeT *PN;
+
+    phi_iterator_impl(PHINodeT *PN) : PN(PN) {}
+
+  public:
+    // Allow default construction to build variables, but this doesn't build
+    // a useful iterator.
+    phi_iterator_impl() = default;
+
+    // Allow conversion between instantiations where valid.
+    template <typename PHINodeU, typename BBIteratorU>
+    phi_iterator_impl(const phi_iterator_impl<PHINodeU, BBIteratorU> &Arg)
+        : PN(Arg.PN) {}
+
+    bool operator==(const phi_iterator_impl &Arg) const { return PN == Arg.PN; }
+
+    PHINodeT &operator*() const { return *PN; }
+
+    using phi_iterator_impl::iterator_facade_base::operator++;
+    phi_iterator_impl &operator++() {
+      assert(PN && "Cannot increment the end iterator!");
+      PN = dyn_cast<PHINodeT>(std::next(BBIteratorT(PN)));
+      return *this;
+    }
+  };
+  typedef phi_iterator_impl<> phi_iterator;
+  typedef phi_iterator_impl<const PHINode, BasicBlock::const_iterator>
+      const_phi_iterator;
+
+  /// Returns a range that iterates over the phis in the basic block.
+  ///
+  /// Note that this cannot be used with basic blocks that have no terminator.
+  iterator_range<const_phi_iterator> phis() const {
+    return const_cast<BasicBlock *>(this)->phis();
+  }
+  iterator_range<phi_iterator> phis();
+
   /// \brief Return the underlying instruction list container.
   ///
   /// Currently you need to access the underlying instruction list container