Index: include/llvm/Support/LowLevelTypeImpl.h
===================================================================
--- include/llvm/Support/LowLevelTypeImpl.h
+++ include/llvm/Support/LowLevelTypeImpl.h
@@ -104,6 +104,10 @@
     return getScalarSizeInBits() * getNumElements();
   }
 
+  LLT getScalarType() const {
+    return isVector() ? getElementType() : *this;
+  }
+
   unsigned getScalarSizeInBits() const {
     assert(RawData != 0 && "Invalid Type");
     if (!IsVector) {
Index: lib/CodeGen/GlobalISel/MachineIRBuilder.cpp
===================================================================
--- lib/CodeGen/GlobalISel/MachineIRBuilder.cpp
+++ lib/CodeGen/GlobalISel/MachineIRBuilder.cpp
@@ -244,11 +244,28 @@
 MachineInstrBuilder MachineIRBuilder::buildConstant(const DstOp &Res,
                                                     const ConstantInt &Val) {
   LLT Ty = Res.getLLTTy(*getMRI());
+  LLT EltTy = Ty.getScalarType();
 
   const ConstantInt *NewVal = &Val;
-  if (Ty.getScalarSizeInBits() != Val.getBitWidth())
-    NewVal = ConstantInt::get(getMF().getFunction().getContext(),
-                              Val.getValue().sextOrTrunc(Ty.getSizeInBits()));
+  if (EltTy.getSizeInBits() != Val.getBitWidth()) {
+    NewVal = ConstantInt::get(
+      getMF().getFunction().getContext(),
+      Val.getValue().sextOrTrunc(EltTy.getSizeInBits()));
+  }
+
+  if (Ty.isVector()) {
+    unsigned EltReg = getMRI()->createGenericVirtualRegister(EltTy);
+    buildInstr(TargetOpcode::G_CONSTANT)
+      .addDef(EltReg)
+      .addCImm(NewVal);
+
+    auto MIB = buildInstr(TargetOpcode::G_BUILD_VECTOR);
+    Res.addDefToMIB(*getMRI(), MIB);
+
+    for (unsigned I = 0, E = Ty.getNumElements(); I != E; ++I)
+      MIB.addUse(EltReg);
+    return MIB;
+  }
 
   auto MIB = buildInstr(TargetOpcode::G_CONSTANT);
   Res.addDefToMIB(*getMRI(), MIB);
@@ -266,7 +283,24 @@
 
 MachineInstrBuilder MachineIRBuilder::buildFConstant(const DstOp &Res,
                                                      const ConstantFP &Val) {
-  assert(!Res.getLLTTy(*getMRI()).isPointer() && "invalid operand type");
+  LLT Ty = Res.getLLTTy(*getMRI());
+
+  assert(!Ty.isPointer() && "invalid operand type");
+
+  if (Ty.isVector()) {
+    unsigned EltReg
+      = getMRI()->createGenericVirtualRegister(Ty.getElementType());
+    buildInstr(TargetOpcode::G_FCONSTANT)
+      .addDef(EltReg)
+      .addFPImm(&Val);
+
+    auto MIB = buildInstr(TargetOpcode::G_BUILD_VECTOR);
+    Res.addDefToMIB(*getMRI(), MIB);
+
+    for (unsigned I = 0, E = Ty.getNumElements(); I != E; ++I)
+      MIB.addUse(EltReg);
+    return MIB;
+  }
 
   auto MIB = buildInstr(TargetOpcode::G_FCONSTANT);
   Res.addDefToMIB(*getMRI(), MIB);