[AVX] Make ListInits Unique

Ensure ListInits are unique and only created once.  This will be
important for AVX as lists will be used extensively to pass generic
patterns, prefix information and other things to lower-level
pattern-generation classes.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136493 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 36 insertions, 1 deletions

diff --git a/utils/TableGen/Record.cpp b/utils/TableGen/Record.cpp
index 133a1581c0..4608d7aa14 100644
--- a/utils/TableGen/Record.cpp
+++ b/utils/TableGen/Record.cpp
@@ -583,8 +583,43 @@ const CodeInit *CodeInit::get(const std::string &V) {
   return I;
 }
 
+static void ProfileListInit(FoldingSetNodeID &ID,
+                            ArrayRef<const Init *> Range,
+                            RecTy *EltTy) {
+  ID.AddInteger(Range.size());
+  ID.AddPointer(EltTy);
+
+  for (ArrayRef<const Init *>::iterator i = Range.begin(),
+         iend = Range.end();
+       i != iend;
+       ++i)
+    ID.AddPointer(*i);
+}
+
 const ListInit *ListInit::get(ArrayRef<const Init *> Range, RecTy *EltTy) {
-  return new ListInit(Range, EltTy);
+  typedef FoldingSet<ListInit> Pool;
+  static Pool ThePool;
+
+  // Just use the FoldingSetNodeID to compute a hash.  Use a DenseMap
+  // for actual storage.
+  FoldingSetNodeID ID;
+  ProfileListInit(ID, Range, EltTy);
+
+  void *IP = 0;
+  if (const ListInit *I = ThePool.FindNodeOrInsertPos(ID, IP))
+    return I;
+
+  ListInit *I = new ListInit(Range, EltTy);
+  ThePool.InsertNode(I, IP);
+  return I;
+}
+
+void ListInit::Profile(FoldingSetNodeID &ID) const {
+  ListRecTy *ListType = dynamic_cast<ListRecTy *>(getType());
+  assert(ListType && "Bad type for ListInit!");
+  RecTy *EltTy = ListType->getElementType();
+
+  ProfileListInit(ID, Values, EltTy);
 }
 
 const Init *