Index: llvm/lib/Analysis/ValueTracking.cpp
===================================================================
--- llvm/lib/Analysis/ValueTracking.cpp
+++ llvm/lib/Analysis/ValueTracking.cpp
@@ -4548,6 +4548,11 @@
       }
       case Intrinsic::exp:
       case Intrinsic::exp2: {
+        KnownFPClass KnownSrc;
+        computeKnownFPClass(II->getArgOperand(0), DemandedElts,
+                            InterestedClasses, KnownSrc, Depth + 1, Q, TLI);
+        if (KnownSrc.isKnownNeverNaN())
+          Known.knownNot(fcNan);
         break;
       }
       case Intrinsic::arithmetic_fence: {
Index: llvm/test/Transforms/Attributor/nofpclass-exp.ll
===================================================================
--- llvm/test/Transforms/Attributor/nofpclass-exp.ll
+++ llvm/test/Transforms/Attributor/nofpclass-exp.ll
@@ -45,9 +45,9 @@
 }
 
 define float @ret_exp_nonan(float nofpclass(nan) %arg0) {
-; CHECK-LABEL: define float @ret_exp_nonan
+; CHECK-LABEL: define nofpclass(nan) float @ret_exp_nonan
 ; CHECK-SAME: (float nofpclass(nan) [[ARG0:%.*]]) #[[ATTR1]] {
-; CHECK-NEXT:    [[CALL:%.*]] = call float @llvm.exp.f32(float [[ARG0]]) #[[ATTR2]]
+; CHECK-NEXT:    [[CALL:%.*]] = call nofpclass(nan) float @llvm.exp.f32(float [[ARG0]]) #[[ATTR2]]
 ; CHECK-NEXT:    ret float [[CALL]]
 ;
   %call = call float @llvm.exp.f32(float %arg0)
@@ -55,9 +55,9 @@
 }
 
 define float @ret_exp_nonan_noinf(float nofpclass(nan inf) %arg0) {
-; CHECK-LABEL: define float @ret_exp_nonan_noinf
+; CHECK-LABEL: define nofpclass(nan) float @ret_exp_nonan_noinf
 ; CHECK-SAME: (float nofpclass(nan inf) [[ARG0:%.*]]) #[[ATTR1]] {
-; CHECK-NEXT:    [[CALL:%.*]] = call float @llvm.exp.f32(float [[ARG0]]) #[[ATTR2]]
+; CHECK-NEXT:    [[CALL:%.*]] = call nofpclass(nan) float @llvm.exp.f32(float [[ARG0]]) #[[ATTR2]]
 ; CHECK-NEXT:    ret float [[CALL]]
 ;
   %call = call float @llvm.exp.f32(float %arg0)
@@ -65,9 +65,9 @@
 }
 
 define float @ret_exp_nonan_noinf_nozero(float nofpclass(nan inf zero) %arg0) {
-; CHECK-LABEL: define float @ret_exp_nonan_noinf_nozero
+; CHECK-LABEL: define nofpclass(nan) float @ret_exp_nonan_noinf_nozero
 ; CHECK-SAME: (float nofpclass(nan inf zero) [[ARG0:%.*]]) #[[ATTR1]] {
-; CHECK-NEXT:    [[CALL:%.*]] = call float @llvm.exp.f32(float [[ARG0]]) #[[ATTR2]]
+; CHECK-NEXT:    [[CALL:%.*]] = call nofpclass(nan) float @llvm.exp.f32(float [[ARG0]]) #[[ATTR2]]
 ; CHECK-NEXT:    ret float [[CALL]]
 ;
   %call = call float @llvm.exp.f32(float %arg0)
@@ -95,10 +95,10 @@
 }
 
 define float @ret_exp_positive_source(i32 %arg) {
-; CHECK-LABEL: define float @ret_exp_positive_source
+; CHECK-LABEL: define nofpclass(nan) float @ret_exp_positive_source
 ; CHECK-SAME: (i32 [[ARG:%.*]]) #[[ATTR1]] {
 ; CHECK-NEXT:    [[UITOFP:%.*]] = uitofp i32 [[ARG]] to float
-; CHECK-NEXT:    [[CALL:%.*]] = call float @llvm.exp.f32(float [[UITOFP]]) #[[ATTR2]]
+; CHECK-NEXT:    [[CALL:%.*]] = call nofpclass(nan) float @llvm.exp.f32(float [[UITOFP]]) #[[ATTR2]]
 ; CHECK-NEXT:    ret float [[CALL]]
 ;
   %uitofp = uitofp i32 %arg to float
@@ -108,10 +108,10 @@
 
 ; Could produce a nan because we don't know if the multiply is negative.
 define float @ret_exp_unknown_sign(float nofpclass(nan) %arg0, float nofpclass(nan) %arg1) {
-; CHECK-LABEL: define float @ret_exp_unknown_sign
+; CHECK-LABEL: define nofpclass(nan) float @ret_exp_unknown_sign
 ; CHECK-SAME: (float nofpclass(nan) [[ARG0:%.*]], float nofpclass(nan) [[ARG1:%.*]]) #[[ATTR1]] {
 ; CHECK-NEXT:    [[UNKNOWN_SIGN_NOT_NAN:%.*]] = fmul nnan float [[ARG0]], [[ARG1]]
-; CHECK-NEXT:    [[CALL:%.*]] = call float @llvm.exp.f32(float [[UNKNOWN_SIGN_NOT_NAN]]) #[[ATTR2]]
+; CHECK-NEXT:    [[CALL:%.*]] = call nofpclass(nan) float @llvm.exp.f32(float [[UNKNOWN_SIGN_NOT_NAN]]) #[[ATTR2]]
 ; CHECK-NEXT:    ret float [[CALL]]
 ;
   %unknown.sign.not.nan = fmul nnan float %arg0, %arg1
@@ -160,9 +160,9 @@
 }
 
 define float @ret_exp2_nonan(float nofpclass(nan) %arg0) {
-; CHECK-LABEL: define float @ret_exp2_nonan
+; CHECK-LABEL: define nofpclass(nan) float @ret_exp2_nonan
 ; CHECK-SAME: (float nofpclass(nan) [[ARG0:%.*]]) #[[ATTR1]] {
-; CHECK-NEXT:    [[CALL:%.*]] = call float @llvm.exp2.f32(float [[ARG0]]) #[[ATTR2]]
+; CHECK-NEXT:    [[CALL:%.*]] = call nofpclass(nan) float @llvm.exp2.f32(float [[ARG0]]) #[[ATTR2]]
 ; CHECK-NEXT:    ret float [[CALL]]
 ;
   %call = call float @llvm.exp2.f32(float %arg0)
@@ -170,9 +170,9 @@
 }
 
 define float @ret_exp2_nonan_noinf(float nofpclass(nan inf) %arg0) {
-; CHECK-LABEL: define float @ret_exp2_nonan_noinf
+; CHECK-LABEL: define nofpclass(nan) float @ret_exp2_nonan_noinf
 ; CHECK-SAME: (float nofpclass(nan inf) [[ARG0:%.*]]) #[[ATTR1]] {
-; CHECK-NEXT:    [[CALL:%.*]] = call float @llvm.exp2.f32(float [[ARG0]]) #[[ATTR2]]
+; CHECK-NEXT:    [[CALL:%.*]] = call nofpclass(nan) float @llvm.exp2.f32(float [[ARG0]]) #[[ATTR2]]
 ; CHECK-NEXT:    ret float [[CALL]]
 ;
   %call = call float @llvm.exp2.f32(float %arg0)
@@ -180,9 +180,9 @@
 }
 
 define float @ret_exp2_nonan_noinf_nozero(float nofpclass(nan inf zero) %arg0) {
-; CHECK-LABEL: define float @ret_exp2_nonan_noinf_nozero
+; CHECK-LABEL: define nofpclass(nan) float @ret_exp2_nonan_noinf_nozero
 ; CHECK-SAME: (float nofpclass(nan inf zero) [[ARG0:%.*]]) #[[ATTR1]] {
-; CHECK-NEXT:    [[CALL:%.*]] = call float @llvm.exp2.f32(float [[ARG0]]) #[[ATTR2]]
+; CHECK-NEXT:    [[CALL:%.*]] = call nofpclass(nan) float @llvm.exp2.f32(float [[ARG0]]) #[[ATTR2]]
 ; CHECK-NEXT:    ret float [[CALL]]
 ;
   %call = call float @llvm.exp2.f32(float %arg0)
@@ -210,10 +210,10 @@
 }
 
 define float @ret_exp2_positive_source(i32 %arg) {
-; CHECK-LABEL: define float @ret_exp2_positive_source
+; CHECK-LABEL: define nofpclass(nan) float @ret_exp2_positive_source
 ; CHECK-SAME: (i32 [[ARG:%.*]]) #[[ATTR1]] {
 ; CHECK-NEXT:    [[UITOFP:%.*]] = uitofp i32 [[ARG]] to float
-; CHECK-NEXT:    [[CALL:%.*]] = call float @llvm.exp2.f32(float [[UITOFP]]) #[[ATTR2]]
+; CHECK-NEXT:    [[CALL:%.*]] = call nofpclass(nan) float @llvm.exp2.f32(float [[UITOFP]]) #[[ATTR2]]
 ; CHECK-NEXT:    ret float [[CALL]]
 ;
   %uitofp = uitofp i32 %arg to float
@@ -223,10 +223,10 @@
 
 ; Could produce a nan because we don't know if the multiply is negative.
 define float @ret_exp2_unknown_sign(float nofpclass(nan) %arg0, float nofpclass(nan) %arg1) {
-; CHECK-LABEL: define float @ret_exp2_unknown_sign
+; CHECK-LABEL: define nofpclass(nan) float @ret_exp2_unknown_sign
 ; CHECK-SAME: (float nofpclass(nan) [[ARG0:%.*]], float nofpclass(nan) [[ARG1:%.*]]) #[[ATTR1]] {
 ; CHECK-NEXT:    [[UNKNOWN_SIGN_NOT_NAN:%.*]] = fmul nnan float [[ARG0]], [[ARG1]]
-; CHECK-NEXT:    [[CALL:%.*]] = call float @llvm.exp2.f32(float [[UNKNOWN_SIGN_NOT_NAN]]) #[[ATTR2]]
+; CHECK-NEXT:    [[CALL:%.*]] = call nofpclass(nan) float @llvm.exp2.f32(float [[UNKNOWN_SIGN_NOT_NAN]]) #[[ATTR2]]
 ; CHECK-NEXT:    ret float [[CALL]]
 ;
   %unknown.sign.not.nan = fmul nnan float %arg0, %arg1