2 files changed, 37 insertions, 4 deletions

diff --git a/llvm/lib/TableGen/Record.cpp b/llvm/lib/TableGen/Record.cpp
index 480a002b64a..4222a0b57fb 100644
--- a/llvm/lib/TableGen/Record.cpp
+++ b/llvm/lib/TableGen/Record.cpp
@@ -856,6 +856,24 @@ Init *BinOpInit::getStrConcat(Init *I0, Init *I1) {
   return BinOpInit::get(BinOpInit::STRCONCAT, I0, I1, StringRecTy::get());
 }
 
+static ListInit *ConcatListInits(const ListInit *LHS,
+                                 const ListInit *RHS) {
+  SmallVector<Init *, 8> Args;
+  Args.insert(Args.end(), LHS->begin(), LHS->end());
+  Args.insert(Args.end(), RHS->begin(), RHS->end());
+  return ListInit::get(Args, LHS->getElementType());
+}
+
+Init *BinOpInit::getListConcat(TypedInit *LHS, Init *RHS) {
+  assert(isa<ListRecTy>(LHS->getType()) && "First arg must be a list");
+
+  // Shortcut for the common case of concatenating two lists.
+   if (const ListInit *LHSList = dyn_cast<ListInit>(LHS))
+     if (const ListInit *RHSList = dyn_cast<ListInit>(RHS))
+       return ConcatListInits(LHSList, RHSList);
+   return BinOpInit::get(BinOpInit::LISTCONCAT, LHS, RHS, LHS->getType());
+}
+
 Init *BinOpInit::Fold(Record *CurRec) const {
   switch (getOpcode()) {
   case CONCAT: {
diff --git a/llvm/lib/TableGen/TGParser.cpp b/llvm/lib/TableGen/TGParser.cpp
index 58343bda275..90c9b390e10 100644
--- a/llvm/lib/TableGen/TGParser.cpp
+++ b/llvm/lib/TableGen/TGParser.cpp
@@ -2119,16 +2119,31 @@ Init *TGParser::ParseValue(Record *CurRec, RecTy *ItemType, IDParseMode Mode) {
 
     case tgtok::paste:
       SMLoc PasteLoc = Lex.getLoc();
-
-      // Create a !strconcat() operation, first casting each operand to
-      // a string if necessary.
-
       TypedInit *LHS = dyn_cast<TypedInit>(Result);
       if (!LHS) {
         Error(PasteLoc, "LHS of paste is not typed!");
         return nullptr;
       }
 
+      // Check if it's a 'listA # listB'
+      if (isa<ListRecTy>(LHS->getType())) {
+        Lex.Lex();  // Eat the '#'.
+
+        switch (Lex.getCode()) {
+        case tgtok::colon:
+        case tgtok::semi:
+        case tgtok::l_brace:
+          Result = LHS; // trailing paste, ignore.
+          break;
+        default:
+          Init *RHSResult = ParseValue(CurRec, ItemType, ParseNameMode);
+          Result = BinOpInit::getListConcat(LHS, RHSResult);
+        }
+        break;
+      }
+
+      // Create a !strconcat() operation, first casting each operand to
+      // a string if necessary.
       if (LHS->getType() != StringRecTy::get()) {
         LHS = dyn_cast<TypedInit>(
             UnOpInit::get(UnOpInit::CAST, LHS, StringRecTy::get())