diff --git a/lib/CodeGen/RegAllocFast.cpp b/lib/CodeGen/RegAllocFast.cpp
index b3832221514..8a22e632734 100644
--- a/lib/CodeGen/RegAllocFast.cpp
+++ b/lib/CodeGen/RegAllocFast.cpp
@@ -711,13 +711,10 @@ void RAFast::handleThroughOperands(MachineInstr *MI,
     if (!MO.isReg() || !MO.isDef()) continue;
     unsigned Reg = MO.getReg();
     if (!Reg || !TargetRegisterInfo::isPhysicalRegister(Reg)) continue;
-    UsedInInstr.set(Reg);
-    if (ThroughRegs.count(PhysRegState[Reg]))
-      definePhysReg(MI, Reg, regFree);
-    for (const uint16_t *AS = TRI->getAliasSet(Reg); *AS; ++AS) {
-      UsedInInstr.set(*AS);
-      if (ThroughRegs.count(PhysRegState[*AS]))
-        definePhysReg(MI, *AS, regFree);
+    for (MCRegAliasIterator AI(Reg, TRI, true); AI.isValid(); ++AI) {
+      UsedInInstr.set(*AI);
+      if (ThroughRegs.count(PhysRegState[*AI]))
+        definePhysReg(MI, *AI, regFree);
     }
   }
 
@@ -1036,9 +1033,8 @@ void RAFast::AllocateBasicBlock() {
         if (!Reg || !TargetRegisterInfo::isPhysicalRegister(Reg)) continue;
         // Look for physreg defs and tied uses.
         if (!MO.isDef() && !MI->isRegTiedToDefOperand(i)) continue;
-        UsedInInstr.set(Reg);
-        for (const uint16_t *AS = TRI->getAliasSet(Reg); *AS; ++AS)
-          UsedInInstr.set(*AS);
+        for (MCRegAliasIterator AI(Reg, TRI, true); AI.isValid(); ++AI)
+          UsedInInstr.set(*AI);
       }
     }
 
diff --git a/lib/CodeGen/RegisterScavenging.cpp b/lib/CodeGen/RegisterScavenging.cpp
index 03bd82e225d..c965d8715b0 100644
--- a/lib/CodeGen/RegisterScavenging.cpp
+++ b/lib/CodeGen/RegisterScavenging.cpp
@@ -43,10 +43,8 @@ void RegScavenger::setUsed(unsigned Reg) {
 }
 
 bool RegScavenger::isAliasUsed(unsigned Reg) const {
-  if (isUsed(Reg))
-    return true;
-  for (const uint16_t *R = TRI->getAliasSet(Reg); *R; ++R)
-    if (isUsed(*R))
+  for (MCRegAliasIterator AI(Reg, TRI, true); AI.isValid(); ++AI)
+    if (isUsed(*AI))
       return true;
   return false;
 }
@@ -296,9 +294,8 @@ unsigned RegScavenger::findSurvivorReg(MachineBasicBlock::iterator StartMI,
           isVirtKillInsn = true;
         continue;
       }
-      Candidates.reset(MO.getReg());
-      for (const uint16_t *R = TRI->getAliasSet(MO.getReg()); *R; R++)
-        Candidates.reset(*R);
+      for (MCRegAliasIterator AI(MO.getReg(), TRI, true); AI.isValid(); ++AI)
+        Candidates.reset(*AI);
     }
     // If we're not in a virtual reg's live range, this is a valid
     // restore point.
diff --git a/lib/CodeGen/SelectionDAG/ScheduleDAGFast.cpp b/lib/CodeGen/SelectionDAG/ScheduleDAGFast.cpp
index 24da432a47a..b7ce48a4892 100644
--- a/lib/CodeGen/SelectionDAG/ScheduleDAGFast.cpp
+++ b/lib/CodeGen/SelectionDAG/ScheduleDAGFast.cpp
@@ -441,19 +441,14 @@ static bool CheckForLiveRegDef(SUnit *SU, unsigned Reg,
                                SmallVector<unsigned, 4> &LRegs,
                                const TargetRegisterInfo *TRI) {
   bool Added = false;
-  if (LiveRegDefs[Reg] && LiveRegDefs[Reg] != SU) {
-    if (RegAdded.insert(Reg)) {
-      LRegs.push_back(Reg);
-      Added = true;
-    }
-  }
-  for (const uint16_t *Alias = TRI->getAliasSet(Reg); *Alias; ++Alias)
-    if (LiveRegDefs[*Alias] && LiveRegDefs[*Alias] != SU) {
-      if (RegAdded.insert(*Alias)) {
-        LRegs.push_back(*Alias);
+  for (MCRegAliasIterator AI(Reg, TRI, true); AI.isValid(); ++AI) {
+    if (LiveRegDefs[*AI] && LiveRegDefs[*AI] != SU) {
+      if (RegAdded.insert(*AI)) {
+        LRegs.push_back(*AI);
         Added = true;
       }
     }
+  }
   return Added;
 }