Index: llvm/lib/Analysis/ValueTracking.cpp
===================================================================
--- llvm/lib/Analysis/ValueTracking.cpp
+++ llvm/lib/Analysis/ValueTracking.cpp
@@ -4761,6 +4761,12 @@
       }
 
       // The sign for frem is the same as the first operand.
+      if (KnownLHS.cannotBeOrderedLessThanZero())
+        Known.knownNot(KnownFPClass::OrderedLessThanZeroMask);
+      if (KnownLHS.cannotBeOrderedGreaterThanZero())
+        Known.knownNot(KnownFPClass::OrderedGreaterThanZeroMask);
+
+      // See if we can be more aggressive about the sign of 0.
       if (KnownLHS.isKnownNever(fcNegative))
         Known.knownNot(fcNegative);
       if (KnownLHS.isKnownNever(fcPositive))
Index: llvm/test/Transforms/Attributor/nofpclass-frem.ll
===================================================================
--- llvm/test/Transforms/Attributor/nofpclass-frem.ll
+++ llvm/test/Transforms/Attributor/nofpclass-frem.ll
@@ -396,7 +396,7 @@
 }
 
 define float @ret_frem_no_neg_lhs(float nofpclass(ninf nsub nnorm) %arg0, float %arg1) #0 {
-; CHECK-LABEL: define float @ret_frem_no_neg_lhs
+; CHECK-LABEL: define nofpclass(ninf nsub nnorm) float @ret_frem_no_neg_lhs
 ; CHECK-SAME: (float nofpclass(ninf nsub nnorm) [[ARG0:%.*]], float [[ARG1:%.*]]) #[[ATTR0]] {
 ; CHECK-NEXT:    [[FREM:%.*]] = frem float [[ARG0]], [[ARG1]]
 ; CHECK-NEXT:    ret float [[FREM]]
@@ -426,7 +426,7 @@
 }
 
 define float @ret_frem_no_neg(float nofpclass(ninf nsub nnorm) %arg0, float nofpclass(ninf nsub nnorm) %arg1) #0 {
-; CHECK-LABEL: define float @ret_frem_no_neg
+; CHECK-LABEL: define nofpclass(ninf nsub nnorm) float @ret_frem_no_neg
 ; CHECK-SAME: (float nofpclass(ninf nsub nnorm) [[ARG0:%.*]], float nofpclass(ninf nsub nnorm) [[ARG1:%.*]]) #[[ATTR0]] {
 ; CHECK-NEXT:    [[FREM:%.*]] = frem float [[ARG0]], [[ARG1]]
 ; CHECK-NEXT:    ret float [[FREM]]
@@ -446,7 +446,7 @@
 }
 
 define float @ret_frem_no_neg_rhs_no_nzero(float nofpclass(ninf nsub nnorm) %arg0, float nofpclass(ninf nsub nnorm nzero) %arg1) #0 {
-; CHECK-LABEL: define float @ret_frem_no_neg_rhs_no_nzero
+; CHECK-LABEL: define nofpclass(ninf nsub nnorm) float @ret_frem_no_neg_rhs_no_nzero
 ; CHECK-SAME: (float nofpclass(ninf nsub nnorm) [[ARG0:%.*]], float nofpclass(ninf nzero nsub nnorm) [[ARG1:%.*]]) #[[ATTR0]] {
 ; CHECK-NEXT:    [[FREM:%.*]] = frem float [[ARG0]], [[ARG1]]
 ; CHECK-NEXT:    ret float [[FREM]]
@@ -486,7 +486,7 @@
 }
 
 define float @ret_frem_no_pos_zero_lhs(float nofpclass(pinf psub pnorm) %arg0, float %arg1) #0 {
-; CHECK-LABEL: define float @ret_frem_no_pos_zero_lhs
+; CHECK-LABEL: define nofpclass(pinf psub pnorm) float @ret_frem_no_pos_zero_lhs
 ; CHECK-SAME: (float nofpclass(pinf psub pnorm) [[ARG0:%.*]], float [[ARG1:%.*]]) #[[ATTR0]] {
 ; CHECK-NEXT:    [[FREM:%.*]] = frem float [[ARG0]], [[ARG1]]
 ; CHECK-NEXT:    ret float [[FREM]]