Move def_chain iterator to MemorySSA.h so it can be reused

llvm-svn: 299297

1 files changed, 0 insertions, 36 deletions

diff --git a/llvm/lib/Transforms/Utils/MemorySSA.cpp b/llvm/lib/Transforms/Utils/MemorySSA.cpp
index 35a63bf9d3d..5a3b163992e 100644
--- a/llvm/lib/Transforms/Utils/MemorySSA.cpp
+++ b/llvm/lib/Transforms/Utils/MemorySSA.cpp
@@ -375,42 +375,6 @@ public:
   }
 };
 
-/// Walks the defining uses of MemoryDefs. Stops after we hit something that has
-/// no defining use (e.g. a MemoryPhi or liveOnEntry). Note that, when comparing
-/// against a null def_chain_iterator, this will compare equal only after
-/// walking said Phi/liveOnEntry.
-struct def_chain_iterator
-    : public iterator_facade_base<def_chain_iterator, std::forward_iterator_tag,
-                                  MemoryAccess *> {
-  def_chain_iterator() : MA(nullptr) {}
-  def_chain_iterator(MemoryAccess *MA) : MA(MA) {}
-
-  MemoryAccess *operator*() const { return MA; }
-
-  def_chain_iterator &operator++() {
-    // N.B. liveOnEntry has a null defining access.
-    if (auto *MUD = dyn_cast<MemoryUseOrDef>(MA))
-      MA = MUD->getDefiningAccess();
-    else
-      MA = nullptr;
-    return *this;
-  }
-
-  bool operator==(const def_chain_iterator &O) const { return MA == O.MA; }
-
-private:
-  MemoryAccess *MA;
-};
-
-static iterator_range<def_chain_iterator>
-def_chain(MemoryAccess *MA, MemoryAccess *UpTo = nullptr) {
-#ifdef EXPENSIVE_CHECKS
-  assert((!UpTo || find(def_chain(MA), UpTo) != def_chain_iterator()) &&
-         "UpTo isn't in the def chain!");
-#endif
-  return make_range(def_chain_iterator(MA), def_chain_iterator(UpTo));
-}
-
 /// Verifies that `Start` is clobbered by `ClobberAt`, and that nothing
 /// inbetween `Start` and `ClobberAt` can clobbers `Start`.
 ///