Revert "TableGen: Fix typeIsConvertibleTo for record types"

This reverts r325884.

Clang's TableGen has dependencies on the exact ordering of superclasses.
Revert this change fully for now to fix the build.

Change-Id: Ib297f5571cc7809f00838702ad7ab53d47335b26
llvm-svn: 325891
diff --git a/llvm/lib/TableGen/Record.cpp b/llvm/lib/TableGen/Record.cpp
index c94bd59..80c0973 100644
--- a/llvm/lib/TableGen/Record.cpp
+++ b/llvm/lib/TableGen/Record.cpp
@@ -141,6 +141,10 @@
   if (RTy->getRecord() == Rec || Rec->isSubClassOf(RTy->getRecord()))
     return true;
 
+  for (const auto &SCPair : RTy->getRecord()->getSuperClasses())
+    if (Rec->isSubClassOf(SCPair.first))
+      return true;
+
   return false;
 }
 
@@ -169,16 +173,6 @@
         return NewType2;
     }
   }
-
-  if (ListRecTy *ListTy1 = dyn_cast<ListRecTy>(T1)) {
-    if (ListRecTy *ListTy2 = dyn_cast<ListRecTy>(T2)) {
-      RecTy* NewType = resolveTypes(ListTy1->getElementType(),
-                                    ListTy2->getElementType());
-      if (NewType)
-        return NewType->getListTy();
-    }
-  }
-
   return nullptr;
 }
 
diff --git a/llvm/lib/TableGen/TGParser.cpp b/llvm/lib/TableGen/TGParser.cpp
index 4dd05fd..10345b9 100644
--- a/llvm/lib/TableGen/TGParser.cpp
+++ b/llvm/lib/TableGen/TGParser.cpp
@@ -198,8 +198,6 @@
 
   // Since everything went well, we can now set the "superclass" list for the
   // current record.
-  CurRec->addSuperClass(SC, SubClass.RefRange);
-
   ArrayRef<std::pair<Record *, SMRange>> SCs = SC->getSuperClasses();
   for (const auto &SCPair : SCs) {
     if (CurRec->isSubClassOf(SCPair.first))
@@ -207,6 +205,11 @@
                    "Already subclass of '" + SCPair.first->getName() + "'!\n");
     CurRec->addSuperClass(SCPair.first, SCPair.second);
   }
+
+  if (CurRec->isSubClassOf(SC))
+    return Error(SubClass.RefRange.Start,
+                 "Already subclass of '" + SC->getName() + "'!\n");
+  CurRec->addSuperClass(SC, SubClass.RefRange);
   return false;
 }
 
@@ -1064,10 +1067,12 @@
         return nullptr;
       }
 
-      Type = resolveTypes(MHSTy, RHSTy);
-      if (!Type) {
-        TokError(Twine("inconsistent types '") + MHSTy->getAsString() +
-                 "' and '" + RHSTy->getAsString() + "' for !if");
+      if (MHSTy->typeIsConvertibleTo(RHSTy)) {
+        Type = RHSTy;
+      } else if (RHSTy->typeIsConvertibleTo(MHSTy)) {
+        Type = MHSTy;
+      } else {
+        TokError("inconsistent types for !if");
         return nullptr;
       }
       break;
diff --git a/llvm/test/TableGen/if-type.td b/llvm/test/TableGen/if-type.td
deleted file mode 100644
index 809195b..0000000
--- a/llvm/test/TableGen/if-type.td
+++ /dev/null
@@ -1,11 +0,0 @@
-// RUN: not llvm-tblgen %s 2>&1 | FileCheck %s
-// XFAIL: vg_leak
-
-class A<int dummy> {}
-class B<int dummy> : A<dummy> {}
-class C<int dummy> : A<dummy> {}
-
-// CHECK: Value 'x' of type 'C' is incompatible with initializer '{{.*}}' of type 'A'
-class X<int cc, B b, C c> {
-  C x = !if(cc, b, c);
-}
diff --git a/llvm/test/TableGen/if.td b/llvm/test/TableGen/if.td
index f2a4bc1..019e4dd 100644
--- a/llvm/test/TableGen/if.td
+++ b/llvm/test/TableGen/if.td
@@ -69,34 +69,10 @@
 // CHECK-NEXT: int i = 0;
 def DI1: I1<1>;
 
-// CHECK: def DI2 {
+// CHECK: def DI2 {     // I1 I2
 // CHECK-NEXT: int i = 0;
 def DI2: I2<1>;
 
-// Check that !if with operands of different subtypes can initialize a
-// supertype variable.
-//
-// CHECK: def EXd1 {
-// CHECK:   E x = E1d;
-// CHECK: }
-//
-// CHECK: def EXd2 {
-// CHECK:   E x = E2d;
-// CHECK: }
-class E<int dummy> {}
-class E1<int dummy> : E<dummy> {}
-class E2<int dummy> : E<dummy> {}
-
-class EX<int cc, E1 b, E2 c> {
-  E x = !if(cc, b, c);
-}
-
-def E1d : E1<0>;
-def E2d : E2<0>;
-
-def EXd1 : EX<1, E1d, E2d>;
-def EXd2 : EX<0, E1d, E2d>;
-
 // CHECK:      def One
 // CHECK-NEXT: list<int> first = [1, 2, 3];
 // CHECK-NEXT: list<int> rest = [1, 2, 3];