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/CallingConvLower.cpp b/lib/CodeGen/CallingConvLower.cpp
index 2b7dfdb..b2c976b 100644
--- a/lib/CodeGen/CallingConvLower.cpp
+++ b/lib/CodeGen/CallingConvLower.cpp
@@ -58,9 +58,8 @@
 
 /// MarkAllocated - Mark a register and all of its aliases as allocated.
 void CCState::MarkAllocated(unsigned Reg) {
-  for (const uint16_t *Alias = TRI.getOverlaps(Reg);
-       unsigned Reg = *Alias; ++Alias)
-    UsedRegs[Reg/32] |= 1 << (Reg&31);
+  for (MCRegAliasIterator AI(Reg, &TRI, true); AI.isValid(); ++AI)
+    UsedRegs[*AI/32] |= 1 << (*AI&31);
 }
 
 /// AnalyzeFormalArguments - Analyze an array of argument values,