Index: llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
===================================================================
--- llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -14040,7 +14040,8 @@
 }
 
 static SDValue visitFMinMax(SelectionDAG &DAG, SDNode *N,
-                            APFloat (*Op)(const APFloat &, const APFloat &)) {
+                            APFloat (*Op)(const APFloat &, const APFloat &),
+                            bool PropagatesNaN) {
   SDValue N0 = N->getOperand(0);
   SDValue N1 = N->getOperand(1);
   EVT VT = N->getValueType(0);
@@ -14058,23 +14059,28 @@
       !isConstantFPBuildVectorOrConstantFP(N1))
     return DAG.getNode(N->getOpcode(), SDLoc(N), VT, N1, N0);
 
+  // minnum(X, nan) -> X
+  // maxnum(X, nan) -> X
+  if (!PropagatesNaN && N1CFP && N1CFP->isNaN())
+    return N->getOperand(0);
+
   return SDValue();
 }
 
 SDValue DAGCombiner::visitFMINNUM(SDNode *N) {
-  return visitFMinMax(DAG, N, minnum);
+  return visitFMinMax(DAG, N, minnum, /* PropagatesNaN */ false);
 }
 
 SDValue DAGCombiner::visitFMAXNUM(SDNode *N) {
-  return visitFMinMax(DAG, N, maxnum);
+  return visitFMinMax(DAG, N, maxnum, /* PropagatesNaN */ false);
 }
 
 SDValue DAGCombiner::visitFMINIMUM(SDNode *N) {
-  return visitFMinMax(DAG, N, minimum);
+  return visitFMinMax(DAG, N, minimum, /* PropagatesNaN */ true);
 }
 
 SDValue DAGCombiner::visitFMAXIMUM(SDNode *N) {
-  return visitFMinMax(DAG, N, maximum);
+  return visitFMinMax(DAG, N, maximum, /* PropagatesNaN */ true);
 }
 
 SDValue DAGCombiner::visitFABS(SDNode *N) {
Index: llvm/test/CodeGen/X86/fmaxnum.ll
===================================================================
--- llvm/test/CodeGen/X86/fmaxnum.ll
+++ llvm/test/CodeGen/X86/fmaxnum.ll
@@ -610,35 +610,9 @@
 }
 
 define float @test_maxnum_const_nan(float %x) {
-; SSE-LABEL: test_maxnum_const_nan:
-; SSE:       # %bb.0:
-; SSE-NEXT:    movss {{.*#+}} xmm2 = mem[0],zero,zero,zero
-; SSE-NEXT:    movaps %xmm0, %xmm1
-; SSE-NEXT:    cmpunordss %xmm0, %xmm1
-; SSE-NEXT:    movaps %xmm1, %xmm3
-; SSE-NEXT:    andps %xmm2, %xmm3
-; SSE-NEXT:    maxss %xmm0, %xmm2
-; SSE-NEXT:    andnps %xmm2, %xmm1
-; SSE-NEXT:    orps %xmm3, %xmm1
-; SSE-NEXT:    movaps %xmm1, %xmm0
-; SSE-NEXT:    retq
-;
-; AVX1-LABEL: test_maxnum_const_nan:
-; AVX1:       # %bb.0:
-; AVX1-NEXT:    vmovss {{.*#+}} xmm1 = mem[0],zero,zero,zero
-; AVX1-NEXT:    vmaxss %xmm0, %xmm1, %xmm2
-; AVX1-NEXT:    vcmpunordss %xmm0, %xmm0, %xmm0
-; AVX1-NEXT:    vblendvps %xmm0, %xmm1, %xmm2, %xmm0
-; AVX1-NEXT:    retq
-;
-; AVX512-LABEL: test_maxnum_const_nan:
-; AVX512:       # %bb.0:
-; AVX512-NEXT:    vmovss {{.*#+}} xmm2 = mem[0],zero,zero,zero
-; AVX512-NEXT:    vmaxss %xmm0, %xmm2, %xmm1
-; AVX512-NEXT:    vcmpunordss %xmm0, %xmm0, %k1
-; AVX512-NEXT:    vmovss %xmm2, %xmm1, %xmm1 {%k1}
-; AVX512-NEXT:    vmovaps %xmm1, %xmm0
-; AVX512-NEXT:    retq
+; CHECK-LABEL: test_maxnum_const_nan:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    retq
   %r = call float @llvm.maxnum.f32(float %x, float 0x7fff000000000000)
   ret float %r
 }
Index: llvm/test/CodeGen/X86/fminnum.ll
===================================================================
--- llvm/test/CodeGen/X86/fminnum.ll
+++ llvm/test/CodeGen/X86/fminnum.ll
@@ -610,35 +610,9 @@
 }
 
 define float @test_minnum_const_nan(float %x) {
-; SSE-LABEL: test_minnum_const_nan:
-; SSE:       # %bb.0:
-; SSE-NEXT:    movss {{.*#+}} xmm2 = mem[0],zero,zero,zero
-; SSE-NEXT:    movaps %xmm0, %xmm1
-; SSE-NEXT:    cmpunordss %xmm0, %xmm1
-; SSE-NEXT:    movaps %xmm1, %xmm3
-; SSE-NEXT:    andps %xmm2, %xmm3
-; SSE-NEXT:    minss %xmm0, %xmm2
-; SSE-NEXT:    andnps %xmm2, %xmm1
-; SSE-NEXT:    orps %xmm3, %xmm1
-; SSE-NEXT:    movaps %xmm1, %xmm0
-; SSE-NEXT:    retq
-;
-; AVX1-LABEL: test_minnum_const_nan:
-; AVX1:       # %bb.0:
-; AVX1-NEXT:    vmovss {{.*#+}} xmm1 = mem[0],zero,zero,zero
-; AVX1-NEXT:    vminss %xmm0, %xmm1, %xmm2
-; AVX1-NEXT:    vcmpunordss %xmm0, %xmm0, %xmm0
-; AVX1-NEXT:    vblendvps %xmm0, %xmm1, %xmm2, %xmm0
-; AVX1-NEXT:    retq
-;
-; AVX512-LABEL: test_minnum_const_nan:
-; AVX512:       # %bb.0:
-; AVX512-NEXT:    vmovss {{.*#+}} xmm2 = mem[0],zero,zero,zero
-; AVX512-NEXT:    vminss %xmm0, %xmm2, %xmm1
-; AVX512-NEXT:    vcmpunordss %xmm0, %xmm0, %k1
-; AVX512-NEXT:    vmovss %xmm2, %xmm1, %xmm1 {%k1}
-; AVX512-NEXT:    vmovaps %xmm1, %xmm0
-; AVX512-NEXT:    retq
+; CHECK-LABEL: test_minnum_const_nan:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    retq
   %r = call float @llvm.minnum.f32(float %x, float 0x7fff000000000000)
   ret float %r
 }