From 79175dbbae0069ea29ec1ec854f3d28346d33e71 Mon Sep 17 00:00:00 2001
From: Nicolai Haehnle <nhaehnle@gmail.com>
Date: Wed, 14 Mar 2018 11:00:48 +0000
Subject: [PATCH] TableGen: Allow dag operators to be resolved late

Change-Id: I51bb80fd5c48c8ac441ab11e43d43c1b91b4b590

Differential revision: https://reviews.llvm.org/D44113

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@327495 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/TableGen/Record.cpp         |  9 +++++++--
 test/TableGen/dag-functional.td | 17 +++++++++++++++--
 2 files changed, 22 insertions(+), 4 deletions(-)

diff --git a/lib/TableGen/Record.cpp b/lib/TableGen/Record.cpp
index 48197f04d11..e9325decfac 100644
--- a/lib/TableGen/Record.cpp
+++ b/lib/TableGen/Record.cpp
@@ -859,8 +859,13 @@ Init *BinOpInit::Fold(Record *CurRec, MultiClass *CurMultiClass) const {
     if (LHSs && RHSs) {
       DefInit *LOp = dyn_cast<DefInit>(LHSs->getOperator());
       DefInit *ROp = dyn_cast<DefInit>(RHSs->getOperator());
-      if (!LOp || !ROp || LOp->getDef() != ROp->getDef())
-        PrintFatalError("Concated Dag operators do not match!");
+      if (!LOp || !ROp)
+        break;
+      if (LOp->getDef() != ROp->getDef()) {
+        PrintFatalError(Twine("Concatenated Dag operators do not match: '") +
+                        LHSs->getAsString() + "' vs. '" + RHSs->getAsString() +
+                        "'");
+      }
       SmallVector<Init*, 8> Args;
       SmallVector<StringInit*, 8> ArgNames;
       for (unsigned i = 0, e = LHSs->getNumArgs(); i != e; ++i) {
diff --git a/test/TableGen/dag-functional.td b/test/TableGen/dag-functional.td
index dc1c37c8eca..6baee695ddd 100644
--- a/test/TableGen/dag-functional.td
+++ b/test/TableGen/dag-functional.td
@@ -40,7 +40,13 @@
 // CHECK:   dag d1 = (ops 1, ?:$name1, 2, 3);
 // CHECK: }
 
-def ops;
+// CHECK: def E0 {
+// CHECK:   dag ret = (ops 1, 2);
+// CHECK: }
+
+class Ops;
+
+def ops : Ops;
 
 class Node<int val, string name> {
   int Val = val;
@@ -100,4 +106,11 @@ def C0 : C<[1, 2], ["a", "b"]>;
 
 def D {
   dag d1 = !con((ops 1), (ops $name1), (ops), (ops 2, 3));
-}
\ No newline at end of file
+}
+
+class E<Ops op> {
+  // Allow concatenation of DAG nodes with operators from template arguments.
+  dag ret = !con((op 1), (op 2));
+}
+
+def E0 : E<ops>;