Index: lib/Target/Mips/MipsCallingConv.td
===================================================================
--- lib/Target/Mips/MipsCallingConv.td
+++ lib/Target/Mips/MipsCallingConv.td
@@ -90,6 +90,9 @@
 // Only the return rules are defined here for O32. The rules for argument
 // passing are defined in MipsISelLowering.cpp.
 def RetCC_MipsO32 : CallingConv<[
+  // Promote i1/i8/i16 return values to i32.
+  CCIfType<[i1, i8, i16], CCPromoteToType<i32>>,
+
   // i32 are returned in registers V0, V1, A0, A1
   CCIfType<[i32], CCAssignToReg<[V0, V1, A0, A1]>>,
 
Index: lib/Target/Mips/MipsFastISel.cpp
===================================================================
--- lib/Target/Mips/MipsFastISel.cpp
+++ lib/Target/Mips/MipsFastISel.cpp
@@ -1112,6 +1112,8 @@
       CopyVT = MVT::i32;
 
     unsigned ResultReg = createResultReg(TLI.getRegClassFor(CopyVT));
+    if (!ResultReg)
+      return false;
     BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc,
             TII.get(TargetOpcode::COPY),
             ResultReg).addReg(RVLocs[0].getLocReg());
@@ -1142,7 +1144,7 @@
   MVT RetVT;
   if (CLI.RetTy->isVoidTy())
     RetVT = MVT::isVoid;
-  else if (!isTypeLegal(CLI.RetTy, RetVT))
+  else if (!isTypeSupported(CLI.RetTy, RetVT))
     return false;
 
   for (auto Flag : CLI.OutFlags)