X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=utils%2FTableGen%2FCodeGenInstruction.cpp;h=fb9ad9371bea479846fa816dad02a3554e318c85;hb=8dd6f0c8353f80de6526810899f271d539f6929c;hp=46e6591fdc91ae0924f3ee8f011c65673f9166f5;hpb=2a8cd57566dd0eb62831b4c7429e46947a52a879;p=oota-llvm.git

diff --git a/utils/TableGen/CodeGenInstruction.cpp b/utils/TableGen/CodeGenInstruction.cpp
index 46e6591fdc9..fb9ad9371be 100644
--- a/utils/TableGen/CodeGenInstruction.cpp
+++ b/utils/TableGen/CodeGenInstruction.cpp
@@ -468,9 +468,13 @@ bool CodeGenInstAlias::tryAliasOpMatch(DagInit *Result, unsigned AliasOpNo,
   if (ADI && ADI->getDef()->getName() == "zero_reg") {
 
     // Check if this is an optional def.
-    if (!InstOpRec->isSubClassOf("OptionalDefOperand"))
-      throw TGError(Loc, "reg0 used for result that is not an "
-                    "OptionalDefOperand!");
+    // Tied operands where the source is a sub-operand of a complex operand
+    // need to represent both operands in the alias destination instruction.
+    // Allow zero_reg for the tied portion. This can and should go away once
+    // the MC representation of things doesn't use tied operands at all.
+    //if (!InstOpRec->isSubClassOf("OptionalDefOperand"))
+    //  throw TGError(Loc, "reg0 used for result that is not an "
+    //                "OptionalDefOperand!");
 
     ResOp = ResultOperand(static_cast<Record*>(0));
     return true;
@@ -537,8 +541,11 @@ CodeGenInstAlias::CodeGenInstAlias(Record *R, CodeGenTarget &T) : TheDef(R) {
   unsigned AliasOpNo = 0;
   for (unsigned i = 0, e = ResultInst->Operands.size(); i != e; ++i) {
 
-    // Tied registers don't have an entry in the result dag.
-    if (ResultInst->Operands[i].getTiedRegister() != -1)
+    // Tied registers don't have an entry in the result dag unless they're part
+    // of a complex operand, in which case we include them anyways, as we
+    // don't have any other way to specify the whole operand.
+    if (ResultInst->Operands[i].MINumOperands == 1 &&
+        ResultInst->Operands[i].getTiedRegister() != -1)
       continue;
 
     if (AliasOpNo >= Result->getNumArgs())