Allow direct value types in pattern definitions.

Just like register classes, value types can be used in two ways in
patterns:

  (sext_inreg i32:$src, i16)

In a named leaf node like i32:$src, the value type simply provides the
type of the node directly. This simplifies type inference a lot compared
to the current practice of specifiying types indirectly with register
classes.

As an unnamed leaf node, like i16 above, the value type represents
itself as an MVT::Other immediate.

llvm-svn: 177828

1 files changed, 18 insertions, 2 deletions

diff --git a/llvm/utils/TableGen/CodeGenDAGPatterns.cpp b/llvm/utils/TableGen/CodeGenDAGPatterns.cpp
index d35a2631ffb..5a6960a9825 100644
--- a/llvm/utils/TableGen/CodeGenDAGPatterns.cpp
+++ b/llvm/utils/TableGen/CodeGenDAGPatterns.cpp
@@ -1378,9 +1378,25 @@ static EEVT::TypeSet getImplicitType(Record *R, unsigned ResNo,
     return EEVT::TypeSet();
   }
 
-  if (R->isSubClassOf("ValueType") || R->isSubClassOf("CondCode")) {
+  if (R->isSubClassOf("ValueType")) {
     assert(ResNo == 0 && "This node only has one result!");
-    // Using a VTSDNode or CondCodeSDNode.
+    // An unnamed VTSDNode represents itself as an MVT::Other immediate.
+    //
+    //   (sext_inreg GPR:$src, i16)
+    //                         ~~~
+    if (Unnamed)
+      return EEVT::TypeSet(MVT::Other, TP);
+    // With a name, the ValueType simply provides the type of the named
+    // variable.
+    //
+    //   (sext_inreg i32:$src, i16)
+    //               ~~~~~~~~
+    return EEVT::TypeSet(getValueType(R), TP);
+  }
+
+  if (R->isSubClassOf("CondCode")) {
+    assert(ResNo == 0 && "This node only has one result!");
+    // Using a CondCodeSDNode.
     return EEVT::TypeSet(MVT::Other, TP);
   }