fix a bug where we had an implicit assumption that the

result instruction operand numbering matched the result pattern.

Fixing this allows us to move the xchg/test aliases to the .td file.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@118334 91177308-0d34-0410-b5e6-96231b3b80d8

utils/TableGen/CodeGenInstruction.cpp

@@ -459,3 +459,21 @@ CodeGenInstAlias::CodeGenInstAlias(Record *R, CodeGenTarget &T) : TheDef(R) {
                   " instruction expects " + utostr(ResultInst->Operands.size())+
                   " operands!");
 }
+
+/// getResultInstOperandIndexForResultOperandIndex - Given an index into the
+/// ResultOperands array, translate it to a valid index in ResultInst's
+/// operand list.
+unsigned CodeGenInstAlias::
+getResultInstOperandIndexForResultOperandIndex(unsigned OpNo) const {
+  unsigned OpIdx = 0;
+  
+  for (unsigned i = 0;; ++i) {
+    assert(i != ResultInst->Operands.size() && "Didn't find entry");
+    if (ResultInst->Operands[i].getTiedRegister() != -1)
+      continue;
+
+    if (OpIdx == OpNo) return i;
+
+    ++OpIdx;
+  }
+}