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, 11 insertions, 3 deletions

diff --git a/llvm/utils/TableGen/DAGISelMatcherGen.cpp b/llvm/utils/TableGen/DAGISelMatcherGen.cpp
index 8541390b417..e91fd1e7dde 100644
--- a/llvm/utils/TableGen/DAGISelMatcherGen.cpp
+++ b/llvm/utils/TableGen/DAGISelMatcherGen.cpp
@@ -218,6 +218,17 @@ void MatcherGen::EmitLeafMatchCode(const TreePatternNode *N) {
   }
 
   Record *LeafRec = DI->getDef();
+
+  // A ValueType leaf node can represent a register when named, or itself when
+  // unnamed.
+  if (LeafRec->isSubClassOf("ValueType")) {
+    // A named ValueType leaf always matches: (add i32:$a, i32:$b).
+    if (N->hasName())
+      return;
+    // An unnamed ValueType as in (sext_inreg GPR:$foo, i8).
+    return AddMatcher(new CheckValueTypeMatcher(LeafRec->getName()));
+  }
+
   if (// Handle register references.  Nothing to do here, they always match.
       LeafRec->isSubClassOf("RegisterClass") ||
       LeafRec->isSubClassOf("RegisterOperand") ||
@@ -236,9 +247,6 @@ void MatcherGen::EmitLeafMatchCode(const TreePatternNode *N) {
     return;
   }
 
-  if (LeafRec->isSubClassOf("ValueType"))
-    return AddMatcher(new CheckValueTypeMatcher(LeafRec->getName()));
-
   if (LeafRec->isSubClassOf("CondCode"))
     return AddMatcher(new CheckCondCodeMatcher(LeafRec->getName()));