[RDF] Switch RegisterAggr to a bit vector of register units

This avoids many complications related to the complex register
aliasing schemes.

llvm-svn: 300345
diff --git a/llvm/lib/Target/Hexagon/HexagonOptAddrMode.cpp b/llvm/lib/Target/Hexagon/HexagonOptAddrMode.cpp
index 800d81b..b243de3 100644
--- a/llvm/lib/Target/Hexagon/HexagonOptAddrMode.cpp
+++ b/llvm/lib/Target/Hexagon/HexagonOptAddrMode.cpp
@@ -259,7 +259,7 @@
                      << Print<Liveness::RefMap>(phiUse, *DFG) << "\n");
         if (!phiUse.empty()) {
           for (auto I : phiUse) {
-            if (DR.Reg != I.first)
+            if (!DFG->getPRI().alias(RegisterRef(I.first), DR))
               continue;
             auto phiUseSet = I.second;
             for (auto phiUI : phiUseSet) {