Switch all register list clients to the new MC*Iterator interface.

No functional change intended.

Sorry for the churn. The iterator classes are supposed to help avoid
giant commits like this one in the future. The TableGen-produced
register lists are getting quite large, and it may be necessary to
change the table representation.

This makes it possible to do so without changing all clients (again).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@157854 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/RegAllocPBQP.cpp b/lib/CodeGen/RegAllocPBQP.cpp
index cfdfa59..4084ebb 100644
--- a/lib/CodeGen/RegAllocPBQP.cpp
+++ b/lib/CodeGen/RegAllocPBQP.cpp
@@ -291,15 +291,11 @@
       }
 
       // Also remove any aliases.
-      const uint16_t *aliasItr = tri->getAliasSet(preg);
-      if (aliasItr != 0) {
-        for (; *aliasItr != 0; ++aliasItr) {
-          VRAllowed::iterator eraseItr =
-            std::find(vrAllowed.begin(), vrAllowed.end(), *aliasItr);
-
-          if (eraseItr != vrAllowed.end()) {
-            vrAllowed.erase(eraseItr);
-          }
+      for (MCRegAliasIterator AI(preg, tri, false); AI.isValid(); ++AI) {
+        VRAllowed::iterator eraseItr =
+          std::find(vrAllowed.begin(), vrAllowed.end(), *AI);
+        if (eraseItr != vrAllowed.end()) {
+          vrAllowed.erase(eraseItr);
         }
       }
     }