Index: lib/Transforms/InstCombine/InstCombineCalls.cpp
===================================================================
--- lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -998,6 +998,65 @@
   return nullptr;
 }
 
+Instruction *InstCombiner::getReducedInstruction(IntrinsicInst *II) {
+  Value *Arg0 = II->getArgOperand(0);
+  Value *Arg1 = II->getArgOperand(1);
+  Value *X = nullptr;
+  Value *Y = nullptr;
+
+  if (II->getIntrinsicID() == Intrinsic::maxnum) {
+    // fmax(x, fmin(x, y)) -> select isnan(x)?y:x
+    // fmax(y, fmin(x, y)) -> select isnan(y)?x:y
+    if (match(Arg1, m_FMin(m_Value(X), m_Value(Y)))) {
+      if (Arg0 == X || Arg0 == Y) {
+        IntrinsicInst *I = cast<IntrinsicInst>(Arg1);
+        if (I->hasNoNaNs())
+          return replaceInstUsesWith(*II, Arg0);
+        Instruction *Result = new FCmpInst(II, FCmpInst::FCMP_UNO, Arg0, Arg0);
+        return SelectInst::Create(Result, Arg0 == X ? Y : X, Arg0);
+      }
+    }
+    // fmax(fmin(x, y), x) -> select isnan(x)?y:x
+    // fmax(fmin(x, y), y) -> select isnan(y)?x:y
+    if (match(Arg0, m_FMin(m_Value(X), m_Value(Y)))) {
+      if (Arg1 == X || Arg1 == Y) {
+        IntrinsicInst *I = cast<IntrinsicInst>(Arg0);
+        if (I->hasNoNaNs())
+          return replaceInstUsesWith(*II, Arg1);
+        Instruction *Result = new FCmpInst(II, FCmpInst::FCMP_UNO, Arg1, Arg1);
+        return SelectInst::Create(Result, Arg1 == X ? Y : X, Arg1);
+      }
+    }
+
+  } else {
+    // fmin(x, fmax(x, y)) -> select isnan(x)?y:x
+    // fmin(y, fmax(x, y)) -> select isnan(y)?x:y
+    if (match(Arg1, m_FMax(m_Value(X), m_Value(Y)))) {
+      if (Arg0 == X || Arg0 == Y) {
+        IntrinsicInst *I = cast<IntrinsicInst>(Arg1);
+        if (I->hasNoNaNs())
+          return replaceInstUsesWith(*II, Arg0);
+        Instruction *Result = new FCmpInst(II, FCmpInst::FCMP_UNO, Arg0, Arg0);
+        return SelectInst::Create(Result, Arg0 == X ? Y : X, Arg0);
+      }
+    }
+
+    // fmin(fmax(x, y), x) -> select isnan(x)?y:x
+    // fmin(fmax(x, y), y) -> select isnan(y)?x:y
+    if (match(Arg0, m_FMax(m_Value(X), m_Value(Y)))) {
+      if (Arg1 == X || Arg1 == Y) {
+        IntrinsicInst *I = cast<IntrinsicInst>(Arg0);
+        if (I->hasNoNaNs())
+          return replaceInstUsesWith(*II, Arg1);
+        Instruction *Result = new FCmpInst(II, FCmpInst::FCMP_UNO, Arg1, Arg1);
+        return SelectInst::Create(Result, Arg1 == X ? Y : X, Arg1);
+      }
+    }
+  }
+
+  return nullptr;
+}
+
 static Value *simplifyMinnumMaxnum(const IntrinsicInst &II) {
   Value *Arg0 = II.getArgOperand(0);
   Value *Arg1 = II.getArgOperand(1);
@@ -1524,6 +1583,10 @@
     }
     if (Value *V = simplifyMinnumMaxnum(*II))
       return replaceInstUsesWith(*II, V);
+
+    if (Instruction *I = getReducedInstruction(II))
+      return I;
+
     break;
   }
   case Intrinsic::ppc_altivec_lvx:
Index: lib/Transforms/InstCombine/InstCombineInternal.h
===================================================================
--- lib/Transforms/InstCombine/InstCombineInternal.h
+++ lib/Transforms/InstCombine/InstCombineInternal.h
@@ -172,6 +172,8 @@
 
   bool MadeIRChange;
 
+  Instruction *getReducedInstruction(IntrinsicInst *II);
+
 public:
   InstCombiner(InstCombineWorklist &Worklist, BuilderTy *Builder,
                bool MinimizeSize, bool ExpensiveCombines, AliasAnalysis *AA,
Index: test/Transforms/InstCombine/maxnum.ll
===================================================================
--- test/Transforms/InstCombine/maxnum.ll
+++ test/Transforms/InstCombine/maxnum.ll
@@ -1,6 +1,7 @@
 ; RUN: opt -S -instcombine < %s | FileCheck %s
 
 declare float @llvm.maxnum.f32(float, float) #0
+declare float @llvm.minnum.f32(float, float) #0
 declare float @llvm.maxnum.v2f32(<2 x float>, <2 x float>) #0
 declare <4 x float> @llvm.maxnum.v4f32(<4 x float>, <4 x float>) #0
 
@@ -219,4 +220,48 @@
   ret float %val
 }
 
+; CHECK-LABEL: @maxnum_x_minnum_x_y
+; CHECK-NEXT: %1 = fcmp uno float %x, 0.000000e+00
+; CHECK-NEXT: %b = select i1 %1, float %y, float %x
+; CHECK-NEXT: ret float %b
+define float @maxnum_x_minnum_x_y(float %x, float %y) #0 {
+  %a = call float @llvm.minnum.f32(float %x, float %y) #0
+  %b = call float @llvm.maxnum.f32(float %x, float %a) #0
+  ret float %b
+}
+
+; CHECK-LABEL: @maxnum_x_minnum_x_y_nnan
+; CHECK-NEXT: ret float %x
+define float @maxnum_x_minnum_x_y_nnan(float %x, float %y) #0 {
+  %a = call nnan float @llvm.minnum.f32(float %x, float %y) #0
+  %b = call float @llvm.maxnum.f32(float %x, float %a) #0
+  ret float %b
+}
+
+; CHECK-LABEL: @minnum_x_y_maxnum_y
+; CHECK-NEXT: %1 = fcmp uno float %y, 0.000000e+00
+; CHECK-NEXT: %b = select i1 %1, float %x, float %y
+; CHECK-NEXT: ret float %b
+define float @minnum_x_y_maxnum_y(float %x, float %y) #0 {
+  %a = call float @llvm.minnum.f32(float %x, float %y) #0
+  %b = call float @llvm.maxnum.f32(float %a, float %y) #0
+  ret float %b
+}
+
+; CHECK-LABEL: @minnum_x_y_maxnum_y_nnan
+; CHECK-NEXT: ret float %y
+define float @minnum_x_y_maxnum_y_nnan(float %x, float %y) #0 {
+  %a = call nnan float @llvm.minnum.f32(float %x, float %y) #0
+  %b = call float @llvm.maxnum.f32(float %a, float %y) #0
+  ret float %b
+}
+
+; CHECK-LABEL: @minnum_x_nan_maxnum_nan
+; CHECK-NEXT: ret float %x
+define float @minnum_x_nan_maxnum_nan(float %x) #0 {
+  %a = call float @llvm.minnum.f32(float %x, float 0x7FF8000000000000) #0
+  %b = call float @llvm.maxnum.f32(float %a, float 0x7FF8000000000000) #0
+  ret float %b
+}
+
 attributes #0 = { nounwind readnone }
Index: test/Transforms/InstCombine/minnum.ll
===================================================================
--- test/Transforms/InstCombine/minnum.ll
+++ test/Transforms/InstCombine/minnum.ll
@@ -1,13 +1,13 @@
 ; RUN: opt -S -instcombine < %s | FileCheck %s
 
 declare float @llvm.minnum.f32(float, float) #0
+declare float @llvm.maxnum.f32(float, float) #0
 declare float @llvm.minnum.v2f32(<2 x float>, <2 x float>) #0
 declare <4 x float> @llvm.minnum.v4f32(<4 x float>, <4 x float>) #0
 
 declare double @llvm.minnum.f64(double, double) #0
 declare <2 x double> @llvm.minnum.v2f64(<2 x double>, <2 x double>) #0
 
-declare float @llvm.maxnum.f32(float, float) #0
 
 ; CHECK-LABEL: @constant_fold_minnum_f32
 ; CHECK-NEXT: ret float 1.000000e+00
@@ -206,26 +206,6 @@
   ret float %c
 }
 
-; CHECK-LABEL: @minnum_x_maxnum_x_y
-; CHECK-NEXT: call float @llvm.maxnum.f32
-; CHECK-NEXT: call float @llvm.minnum.f32
-; CHECK-NEXT: ret float
-define float @minnum_x_maxnum_x_y(float %x, float %y) #0 {
-  %a = call float @llvm.maxnum.f32(float %x, float %y) #0
-  %b = call float @llvm.minnum.f32(float %x, float %a) #0
-  ret float %b
-}
-
-; CHECK-LABEL: @maxnum_x_minnum_x_y
-; CHECK-NEXT: call float @llvm.minnum.f32
-; CHECK-NEXT: call float @llvm.maxnum.f32
-; CHECK-NEXT: ret float
-define float @maxnum_x_minnum_x_y(float %x, float %y) #0 {
-  %a = call float @llvm.minnum.f32(float %x, float %y) #0
-  %b = call float @llvm.maxnum.f32(float %x, float %a) #0
-  ret float %b
-}
-
 ; CHECK-LABEL: @fold_minnum_f32_inf_val
 ; CHECK-NEXT: call float @llvm.minnum.f32(float %x, float 0x7FF0000000000000)
 ; CHECK-NEXT: ret float
@@ -241,4 +221,51 @@
   ret float %val
 }
 
+; CHECK-LABEL: @minnum_x_maxnum_x_y
+; CHECK-NEXT: %1 = fcmp uno float %x, 0.000000e+00
+; CHECK-NEXT: %b = select i1 %1, float %y, float %x
+; CHECK-NEXT: ret float %b
+
+define float @minnum_x_maxnum_x_y(float %x, float %y) #0 {
+  %a = call float @llvm.maxnum.f32(float %x, float %y) #0
+  %b = call float @llvm.minnum.f32(float %x, float %a) #0
+  ret float %b
+}
+
+; CHECK-LABEL: @minnum_x_maxnum_x_y_nnan
+; CHECK-NEXT: ret float %x
+
+define float @minnum_x_maxnum_x_y_nnan(float %x, float %y) #0 {
+  %a = call nnan float @llvm.maxnum.f32(float %x, float %y) #0
+  %b = call float @llvm.minnum.f32(float %x, float %a) #0
+  ret float %b
+}
+
+
+; CHECK-LABEL: @maxnum_x_y_minnum_y
+; CHECK-NEXT: %1 = fcmp uno float %y, 0.000000e+00
+; CHECK-NEXT: %b = select i1 %1, float %x, float %y
+; CHECK-NEXT: ret float %b
+define float @maxnum_x_y_minnum_y(float %x, float %y) #0 {
+  %a = call float @llvm.maxnum.f32(float %x, float %y) #0
+  %b = call float @llvm.minnum.f32(float %a, float %y) #0
+  ret float %b
+}
+
+; CHECK-LABEL: @maxnum_x_y_minnum_y_nnan
+; CHECK-NEXT: ret float %y
+define float @maxnum_x_y_minnum_y_nnan(float %x, float %y) #0 {
+  %a = call nnan float @llvm.maxnum.f32(float %x, float %y) #0
+  %b = call float @llvm.minnum.f32(float %a, float %y) #0
+  ret float %b
+}
+
+; CHECK-LABEL: @maxnum_y_nan_minnum_nan
+; CHECK-NEXT: ret float %y
+define float @maxnum_y_nan_minnum_nan(float %y) #0 {
+  %a = call float @llvm.maxnum.f32(float 0x7FF8000000000000, float %y) #0
+  %b = call float @llvm.minnum.f32(float %a,  float 0x7FF8000000000000) #0
+  ret float %b
+}
+
 attributes #0 = { nounwind readnone }