diff --git a/lib/Analysis/ConstantFolding.cpp b/lib/Analysis/ConstantFolding.cpp
index aaab600bfc6..0ddca5a0983 100644
--- a/lib/Analysis/ConstantFolding.cpp
+++ b/lib/Analysis/ConstantFolding.cpp
@@ -2305,6 +2305,25 @@ static Constant *ConstantFoldScalarCall2(StringRef Name,
                                          const CallBase *Call) {
   assert(Operands.size() == 2 && "Wrong number of operands.");
 
+  if (Ty->isFloatingPointTy()) {
+    // TODO: We should have undef handling for all of the FP intrinsics that
+    //       are attempted to be folded in this function.
+    bool IsOp0Undef = isa<UndefValue>(Operands[0]);
+    bool IsOp1Undef = isa<UndefValue>(Operands[1]);
+    switch (IntrinsicID) {
+    case Intrinsic::maxnum:
+    case Intrinsic::minnum:
+    case Intrinsic::maximum:
+    case Intrinsic::minimum:
+      // If one argument is undef, return the other argument.
+      if (IsOp0Undef)
+        return Operands[1];
+      if (IsOp1Undef)
+        return Operands[0];
+      break;
+    }
+  }
+
   if (auto *Op1 = dyn_cast<ConstantFP>(Operands[0])) {
     if (!Ty->isHalfTy() && !Ty->isFloatTy() && !Ty->isDoubleTy())
       return nullptr;
diff --git a/test/Transforms/InstSimplify/ConstProp/fp-undef.ll b/test/Transforms/InstSimplify/ConstProp/fp-undef.ll
index b77337a63a3..fd139f0b880 100644
--- a/test/Transforms/InstSimplify/ConstProp/fp-undef.ll
+++ b/test/Transforms/InstSimplify/ConstProp/fp-undef.ll
@@ -540,7 +540,7 @@ define <2 x double> @frem_undef_op0_constant_vec(<2 x double> %x) {
 
 define <2 x double> @maximum_nan_op0_vec_partial_undef_op1_undef(<2 x double> %x) {
 ; CHECK-LABEL: @maximum_nan_op0_vec_partial_undef_op1_undef(
-; CHECK-NEXT:    ret <2 x double> <double 0x7FF8000000000000, double 0x7FF8000000000000>
+; CHECK-NEXT:    ret <2 x double> <double 0x7FF8000000000000, double undef>
 ;
   %r = call <2 x double> @llvm.maximum.v2f64(<2 x double> <double 0x7ff8000000000000, double undef>, <2 x double> undef)
   ret <2 x double> %r
@@ -556,7 +556,7 @@ define <2 x double> @maximum_nan_op1_vec_partial_undef_op0_undef(<2 x double> %x
 
 define <2 x double> @minimum_nan_op0_vec_partial_undef_op1_undef(<2 x double> %x) {
 ; CHECK-LABEL: @minimum_nan_op0_vec_partial_undef_op1_undef(
-; CHECK-NEXT:    ret <2 x double> <double 0x7FF8000000000000, double 0x7FF8000000000000>
+; CHECK-NEXT:    ret <2 x double> <double 0x7FF8000000000000, double undef>
 ;
   %r = call <2 x double> @llvm.minimum.v2f64(<2 x double> <double 0x7ff8000000000000, double undef>, <2 x double> undef)
   ret <2 x double> %r
@@ -572,7 +572,7 @@ define <2 x double> @minimum_nan_op1_vec_partial_undef_op0_undef(<2 x double> %x
 
 define <2 x double> @maxnum_nan_op0_vec_partial_undef_op1_undef(<2 x double> %x) {
 ; CHECK-LABEL: @maxnum_nan_op0_vec_partial_undef_op1_undef(
-; CHECK-NEXT:    ret <2 x double> undef
+; CHECK-NEXT:    ret <2 x double> <double 0x7FF8000000000000, double undef>
 ;
   %r = call <2 x double> @llvm.maxnum.v2f64(<2 x double> <double 0x7ff8000000000000, double undef>, <2 x double> undef)
   ret <2 x double> %r
@@ -588,7 +588,7 @@ define <2 x double> @maxnum_nan_op1_vec_partial_undef_op0_undef(<2 x double> %x)
 
 define <2 x double> @minnum_nan_op0_vec_partial_undef_op1_undef(<2 x double> %x) {
 ; CHECK-LABEL: @minnum_nan_op0_vec_partial_undef_op1_undef(
-; CHECK-NEXT:    ret <2 x double> undef
+; CHECK-NEXT:    ret <2 x double> <double 0x7FF8000000000000, double undef>
 ;
   %r = call <2 x double> @llvm.minnum.v2f64(<2 x double> <double 0x7ff8000000000000, double undef>, <2 x double> undef)
   ret <2 x double> %r