Minor compile-time optimization; don't bother checking
canClobberPhysRegDefs if the successor node doesn't
clobber any physical registers.

llvm-svn: 67587
diff --git a/llvm/lib/CodeGen/SelectionDAG/ScheduleDAGRRList.cpp b/llvm/lib/CodeGen/SelectionDAG/ScheduleDAGRRList.cpp
index 39c4f4e..30dc476 100644
--- a/llvm/lib/CodeGen/SelectionDAG/ScheduleDAGRRList.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/ScheduleDAGRRList.cpp
@@ -1392,7 +1392,7 @@
           continue;
         // Don't constrain nodes with physical register defs if the
         // predecessor can clobber them.
-        if (SuccSU->hasPhysRegDefs) {
+        if (SuccSU->hasPhysRegDefs && SU->hasPhysRegClobbers) {
           if (canClobberPhysRegDefs(SuccSU, SU, TII, TRI))
             continue;
         }