Allow TableGen DAG arguments to be just a name.

DAG arguments can optionally be named:

  (dag node, node:$name)

With this change, the node is also optional:

  (dag node, node:$name, $name)

The missing node is treated as an UnsetInit, so the above is equivalent
to:

  (dag node, node:$name, ?:$name)

This syntax is useful in output patterns where we currently require the
types of variables to be repeated:

  def : Pat<(subc i32:$b, i32:$c), (SUBCCrr i32:$b, i32:$c)>;

This is preferable:

  def : Pat<(subc i32:$b, i32:$c), (SUBCCrr $b, $c)>;

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@177843 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 12 insertions, 0 deletions

diff --git a/test/TableGen/Dag.td b/test/TableGen/Dag.td
index 40399a4..14d616b 100644
--- a/test/TableGen/Dag.td
+++ b/test/TableGen/Dag.td
@@ -70,3 +70,15 @@ def VAL4 : bar<foo2, somedef2>;
 // CHECK-NEXT:  dag Dag3 = (somedef2 2);
 // CHECK-NEXT:  NAME = ?
 // CHECK-NEXT: }
+
+def VAL5 : bar<foo2, somedef2> {
+  // Named operands.
+  let Dag1 = (somedef1 1:$name1);
+
+  // Name, no node.
+  let Dag2 = (somedef2 $name2, $name3);
+}
+
+// CHECK:      def VAL5 {
+// CHECK-NEXT:  dag Dag1 = (somedef1 1:$name1);
+// CHECK-NEXT:  dag Dag2 = (somedef2 ?:$name2, ?:$name3);