Weight variables by their number of uses for register allocation.

src/IceTargetLoweringX8632.cpp

Index: src/IceTargetLoweringX8632.cpp
diff --git a/src/IceTargetLoweringX8632.cpp b/src/IceTargetLoweringX8632.cpp
index e9f998987ddc9d4bd6506365d458a934b2f90793..a4ceac061f63e4aa9199799df184c9ea84daf8e9 100644
--- a/src/IceTargetLoweringX8632.cpp
+++ b/src/IceTargetLoweringX8632.cpp
@@ -429,7 +429,7 @@ void TargetX8632::addProlog(CfgNode *Node) {
       [&VariablesLinkedToSpillSlots](Variable *Var) {
         if (auto *SpillVar =
                 llvm::dyn_cast<typename Traits::SpillVariable>(Var)) {
-          assert(Var->getWeight().isZero());
+          assert(Var->mustNotHaveReg());
           if (SpillVar->getLinkedTo() && !SpillVar->getLinkedTo()->hasReg()) {
             VariablesLinkedToSpillSlots.push_back(Var);
             return true;