Avoid creating virtual registers for unused values.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@101480 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index 412de1c..71da0ab 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -918,10 +918,10 @@
 /// created for it, emit nodes to copy the value into the virtual
 /// registers.
 void SelectionDAGBuilder::CopyToExportRegsIfNeeded(const Value *V) {
-  if (!V->use_empty()) {
-    DenseMap<const Value *, unsigned>::iterator VMI = FuncInfo.ValueMap.find(V);
-    if (VMI != FuncInfo.ValueMap.end())
-      CopyValueToVirtualRegister(V, VMI->second);
+  DenseMap<const Value *, unsigned>::iterator VMI = FuncInfo.ValueMap.find(V);
+  if (VMI != FuncInfo.ValueMap.end()) {
+    assert(!V->use_empty() && "Unused value assigned virtual registers!");
+    CopyValueToVirtualRegister(V, VMI->second);
   }
 }