[LLVM][TableGen] Support type casts of nodes with multiple results (#109728)

Currently, type casts can only be used to pattern match for intrinsics
with a single overloaded return value. For instance:
```
def int_foo : Intrinsic<[llvm_anyint_ty], []>;
def : Pat<(i32 (int_foo)), ...>;
```

This patch extends type casts to support matching intrinsics with
multiple overloaded return values. As an example, the following defines
a pattern that matches only if the overloaded intrinsic call returns an
`i16` for the first result and an `i32` for the second result:
```
def int_bar : Intrinsic<[llvm_anyint_ty, llvm_anyint_ty], []>;
def : Pat<([i16, i32] (int_bar)), ...>;
```

1 files changed, 5 insertions, 3 deletions

diff --git a/llvm/lib/TableGen/TGParser.cpp b/llvm/lib/TableGen/TGParser.cpp
index e3eed32..5e7b885 100644
--- a/llvm/lib/TableGen/TGParser.cpp
+++ b/llvm/lib/TableGen/TGParser.cpp
@@ -2866,11 +2866,13 @@ Init *TGParser::ParseSimpleValue(Record *CurRec, RecTy *ItemType,
 
     return ListInit::get(Vals, DeducedEltTy);
   }
-  case tgtok::l_paren: {         // Value ::= '(' IDValue DagArgList ')'
+  case tgtok::l_paren: { // Value ::= '(' IDValue DagArgList ')'
+                         // Value ::= '(' '[' ValueList ']' DagArgList ')'
     Lex.Lex();   // eat the '('
     if (Lex.getCode() != tgtok::Id && Lex.getCode() != tgtok::XCast &&
-        Lex.getCode() != tgtok::question && Lex.getCode() != tgtok::XGetDagOp) {
-      TokError("expected identifier in dag init");
+        Lex.getCode() != tgtok::question && Lex.getCode() != tgtok::XGetDagOp &&
+        Lex.getCode() != tgtok::l_square) {
+      TokError("expected identifier or list of value types in dag init");
       return nullptr;
     }