InstSimplify: Use correct interested FP classes when simplifying fcmp

We are interested in the cases that we don't want, so this was
backwards.

Fixes regression reported after ddb3f12

Author: arsenm

llvm/lib/Analysis/InstructionSimplify.cpp

@@ -4129,7 +4129,7 @@ static Value *simplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
     // compare isn't a complete class test. e.g. > 1.0 implies fcPositive, but
     // isn't implementable as a class call.
     if (C->isNegative() && !C->isNegZero()) {
-      FPClassTest Interested = fcPositive | fcNan;
+      FPClassTest Interested = KnownFPClass::OrderedLessThanZeroMask;
 
       // FIXME: This assert won't always hold if we depend on the context
       // instruction above
@@ -4210,11 +4210,13 @@ static Value *simplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
   // TODO: Could fold this with above if there were a matcher which returned all
   // classes in a non-splat vector.
   if (match(RHS, m_AnyZeroFP())) {
-    FPClassTest Interested = FMF.noNaNs() ? fcPositive : fcPositive | fcNan;
-
     switch (Pred) {
     case FCmpInst::FCMP_OGE:
     case FCmpInst::FCMP_ULT: {
+      FPClassTest Interested = KnownFPClass::OrderedLessThanZeroMask;
+      if (!FMF.noNaNs())
+        Interested |= fcNan;
+
       KnownFPClass Known = computeLHSClass(Interested);
 
       // Positive or zero X >= 0.0 --> true
@@ -4226,6 +4228,7 @@ static Value *simplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
     }
     case FCmpInst::FCMP_UGE:
     case FCmpInst::FCMP_OLT: {
+      FPClassTest Interested = KnownFPClass::OrderedLessThanZeroMask;
       KnownFPClass Known = computeLHSClass(Interested);
 
       // Positive or zero or nan X >= 0.0 --> true

llvm/test/Transforms/InstSimplify/floating-point-compare.ll

@@ -1587,9 +1587,7 @@ define float @fast_square_must_be_positive_daz(float %arg, float %arg1) #0 {
 ; CHECK-NEXT:    [[I:%.*]] = fmul float [[ARG:%.*]], [[ARG]]
 ; CHECK-NEXT:    [[I2:%.*]] = fmul float [[ARG1:%.*]], [[ARG1]]
 ; CHECK-NEXT:    [[I3:%.*]] = fadd float [[I2]], [[I]]
-; CHECK-NEXT:    [[I4:%.*]] = fcmp olt float [[I3]], 0.000000e+00
-; CHECK-NEXT:    [[I5:%.*]] = select i1 [[I4]], float 0.000000e+00, float [[I3]]
-; CHECK-NEXT:    ret float [[I5]]
+; CHECK-NEXT:    ret float [[I3]]
 ;
 bb:
   %i = fmul float %arg, %arg
@@ -1607,9 +1605,7 @@ define float @fast_square_must_be_positive_daz_nnan(float %arg, float %arg1) #0
 ; CHECK-NEXT:    [[I:%.*]] = fmul float [[ARG:%.*]], [[ARG]]
 ; CHECK-NEXT:    [[I2:%.*]] = fmul float [[ARG1:%.*]], [[ARG1]]
 ; CHECK-NEXT:    [[I3:%.*]] = fadd float [[I2]], [[I]]
-; CHECK-NEXT:    [[I4:%.*]] = fcmp nnan olt float [[I3]], 0.000000e+00
-; CHECK-NEXT:    [[I5:%.*]] = select i1 [[I4]], float 0.000000e+00, float [[I3]]
-; CHECK-NEXT:    ret float [[I5]]
+; CHECK-NEXT:    ret float [[I3]]
 ;
 bb:
   %i = fmul float %arg, %arg
@@ -1627,9 +1623,7 @@ define float @must_be_olt_negative_constant_daz(float %arg, float %arg1) #0 {
 ; CHECK-NEXT:    [[I:%.*]] = fmul float [[ARG:%.*]], [[ARG]]
 ; CHECK-NEXT:    [[I2:%.*]] = fmul float [[ARG1:%.*]], [[ARG1]]
 ; CHECK-NEXT:    [[I3:%.*]] = fadd float [[I2]], [[I]]
-; CHECK-NEXT:    [[I4:%.*]] = fcmp olt float [[I3]], -1.000000e+00
-; CHECK-NEXT:    [[I5:%.*]] = select i1 [[I4]], float 0.000000e+00, float [[I3]]
-; CHECK-NEXT:    ret float [[I5]]
+; CHECK-NEXT:    ret float [[I3]]
 ;
 bb:
   %i = fmul float %arg, %arg
@@ -1647,9 +1641,7 @@ define float @must_be_olt_negative_constant_daz_nnan(float %arg, float %arg1) #0
 ; CHECK-NEXT:    [[I:%.*]] = fmul float [[ARG:%.*]], [[ARG]]
 ; CHECK-NEXT:    [[I2:%.*]] = fmul float [[ARG1:%.*]], [[ARG1]]
 ; CHECK-NEXT:    [[I3:%.*]] = fadd float [[I2]], [[I]]
-; CHECK-NEXT:    [[I4:%.*]] = fcmp nnan olt float [[I3]], -1.000000e+00
-; CHECK-NEXT:    [[I5:%.*]] = select i1 [[I4]], float 0.000000e+00, float [[I3]]
-; CHECK-NEXT:    ret float [[I5]]
+; CHECK-NEXT:    ret float [[I3]]
 ;
 bb:
   %i = fmul float %arg, %arg