diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h
@@ -284,7 +284,8 @@
     return CurInst ? CurInst->getDebugLoc() : DebugLoc();
   }
 
-  void CopyValueToVirtualRegister(const Value *V, unsigned Reg);
+  void CopyValueToVirtualRegister(const Value *V, unsigned Reg,
+                                  ISD::NodeType ExtendType = ISD::ANY_EXTEND);
 
   void visit(const Instruction &I);
 
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -918,10 +918,7 @@
                                           CallConv.getValue(), RegVTs[Value])
                                     : RegVTs[Value];
 
-    // We need to zero extend constants that are liveout to match assumptions
-    // in FunctionLoweringInfo::ComputePHILiveOutRegInfo.
-    if (ExtendKind == ISD::ANY_EXTEND &&
-        (TLI.isZExtFree(Val, RegisterVT) || isa<ConstantSDNode>(Val)))
+    if (ExtendKind == ISD::ANY_EXTEND && TLI.isZExtFree(Val, RegisterVT))
       ExtendKind = ISD::ZERO_EXTEND;
 
     getCopyToParts(DAG, dl, Val.getValue(Val.getResNo() + Value), &Parts[Part],
@@ -10011,8 +10008,9 @@
   llvm_unreachable("LowerOperation not implemented for this target!");
 }
 
-void
-SelectionDAGBuilder::CopyValueToVirtualRegister(const Value *V, unsigned Reg) {
+void SelectionDAGBuilder::CopyValueToVirtualRegister(const Value *V,
+                                                     unsigned Reg,
+                                                     ISD::NodeType ExtendType) {
   SDValue Op = getNonRegisterValue(V);
   assert((Op.getOpcode() != ISD::CopyFromReg ||
           cast<RegisterSDNode>(Op.getOperand(1))->getReg() != Reg) &&
@@ -10027,10 +10025,11 @@
                    None); // This is not an ABI copy.
   SDValue Chain = DAG.getEntryNode();
 
-  ISD::NodeType ExtendType = ISD::ANY_EXTEND;
-  auto PreferredExtendIt = FuncInfo.PreferredExtendType.find(V);
-  if (PreferredExtendIt != FuncInfo.PreferredExtendType.end())
-    ExtendType = PreferredExtendIt->second;
+  if (ExtendType == ISD::ANY_EXTEND) {
+    auto PreferredExtendIt = FuncInfo.PreferredExtendType.find(V);
+    if (PreferredExtendIt != FuncInfo.PreferredExtendType.end())
+      ExtendType = PreferredExtendIt->second;
+  }
   RFV.getCopyToRegs(Op, DAG, getCurSDLoc(), Chain, nullptr, V, ExtendType);
   PendingExports.push_back(Chain);
 }
@@ -10640,7 +10639,11 @@
         unsigned &RegOut = ConstantsOut[C];
         if (RegOut == 0) {
           RegOut = FuncInfo.CreateRegs(C);
-          CopyValueToVirtualRegister(C, RegOut);
+          // We need to zero extend ConstantInt phi operands to match
+          // assumptions in FunctionLoweringInfo::ComputePHILiveOutRegInfo.
+          ISD::NodeType ExtendType =
+              isa<ConstantInt>(PHIOp) ? ISD::ZERO_EXTEND : ISD::ANY_EXTEND;
+          CopyValueToVirtualRegister(C, RegOut, ExtendType);
         }
         Reg = RegOut;
       } else {