ValueTracking: Handle exp/exp2 in computeKnownFPClass

[arsenm]

Summary

This is the same as isKnownNeverNaN

[kpn]

llvm/lib/Analysis/ValueTracking.cpp

4555

Infinity. In chapter 9.2.1 of 754-2019 it defines exp(0) and exp2(0) as 1. Since we know this isn't infinity, it seems like now is a good time to add a check?

[jcranmer-intel]

llvm/lib/Analysis/ValueTracking.cpp

4555

exp/exp2 is never a negative number, not even -0 (exp(-inf) = +0).

[arsenm]

Never negative

[arsenm]

d46f8c6ec98e3965139d055cc27c34e946f74a1d

llvm/lib/Analysis/ValueTracking.cpp

         // As there's no spec for denormal flushing, be conservative with the
         // treatment of denormals that could be flushed to zero. For older
         // subtargets on AMDGPU the min/max instructions would not flush the
         // output and return the original value.
         //
         // TODO: This could be refined based on the sign
         if ((Known.KnownFPClasses & fcZero) != fcNone &&
             !Known.isKnownNeverSubnormal()) {
           const Function *Parent = II->getFunction();
           DenormalMode Mode = Parent->getDenormalMode(
               II->getType()->getScalarType()->getFltSemantics());
           if (Mode != DenormalMode::getIEEE())
             Known.KnownFPClasses |= fcZero;
         }
 
         break;
       }

           if (KnownSrc.isKnownNever(fcNegNormal))
             Known.knownNot(fcNegNormal);
 
           // Sign should be preserved
           Known.SignBit = KnownSrc.SignBit;
         }
         break;
       }
+      case Intrinsic::exp:
+      case Intrinsic::exp2: {
+        Known.knownNot(fcNegative);
+        if ((InterestedClasses & fcNan) == fcNone)
+          break;
+
+        KnownFPClass KnownSrc;
+        computeKnownFPClass(II->getArgOperand(0), DemandedElts,
+                            InterestedClasses, KnownSrc, Depth + 1, Q, TLI);
+        if (KnownSrc.isKnownNeverNaN()) {
+          Known.knownNot(fcNan);
+          Known.SignBit = false;
+        }
+
+        break;
+      }
       case Intrinsic::arithmetic_fence: {
         computeKnownFPClass(II->getArgOperand(0), DemandedElts,
                             InterestedClasses, Known, Depth + 1, Q, TLI);
         break;
       }
       default:
         break;
       }

llvm/test/Transforms/Attributor/nofpclass-exp.ll

 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 2
 ; RUN: opt -aa-pipeline=basic-aa -passes=attributor -attributor-manifest-internal -S < %s | FileCheck %s --check-prefixes=CHECK,TUNIT
 
 declare float @llvm.exp.f32(float)
 declare float @llvm.exp2.f32(float)
 
 define float @ret_exp(float %arg0) {
-; CHECK-LABEL: define float @ret_exp
+; CHECK-LABEL: define nofpclass(ninf nzero nsub nnorm) float @ret_exp
 ; CHECK-SAME: (float [[ARG0:%.*]]) #[[ATTR1:[0-9]+]] {
-; CHECK-NEXT:    [[CALL:%.*]] = call float @llvm.exp.f32(float [[ARG0]]) #[[ATTR2:[0-9]+]]
+; CHECK-NEXT:    [[CALL:%.*]] = call nofpclass(ninf nzero nsub nnorm) float @llvm.exp.f32(float [[ARG0]]) #[[ATTR2:[0-9]+]]
 ; CHECK-NEXT:    ret float [[CALL]]
 ;
   %call = call float @llvm.exp.f32(float %arg0)
   ret float %call
 }
 
 define float @ret_exp_noinf(float nofpclass(inf) %arg0) {
-; CHECK-LABEL: define float @ret_exp_noinf
+; CHECK-LABEL: define nofpclass(ninf nzero nsub nnorm) float @ret_exp_noinf
 ; CHECK-SAME: (float nofpclass(inf) [[ARG0:%.*]]) #[[ATTR1]] {
-; CHECK-NEXT:    [[CALL:%.*]] = call float @llvm.exp.f32(float [[ARG0]]) #[[ATTR2]]
+; CHECK-NEXT:    [[CALL:%.*]] = call nofpclass(ninf nzero nsub nnorm) float @llvm.exp.f32(float [[ARG0]]) #[[ATTR2]]
 ; CHECK-NEXT:    ret float [[CALL]]
 ;
   %call = call float @llvm.exp.f32(float %arg0)
   ret float %call
 }
 
 define float @ret_exp_nopinf(float nofpclass(pinf) %arg0) {
-; CHECK-LABEL: define float @ret_exp_nopinf
+; CHECK-LABEL: define nofpclass(ninf nzero nsub nnorm) float @ret_exp_nopinf
 ; CHECK-SAME: (float nofpclass(pinf) [[ARG0:%.*]]) #[[ATTR1]] {
-; CHECK-NEXT:    [[CALL:%.*]] = call float @llvm.exp.f32(float [[ARG0]]) #[[ATTR2]]
+; CHECK-NEXT:    [[CALL:%.*]] = call nofpclass(ninf nzero nsub nnorm) float @llvm.exp.f32(float [[ARG0]]) #[[ATTR2]]
 ; CHECK-NEXT:    ret float [[CALL]]
 ;
   %call = call float @llvm.exp.f32(float %arg0)
   ret float %call
 }
 
 define float @ret_exp_noninf(float nofpclass(ninf) %arg0) {
-; CHECK-LABEL: define float @ret_exp_noninf
+; CHECK-LABEL: define nofpclass(ninf nzero nsub nnorm) float @ret_exp_noninf
 ; CHECK-SAME: (float nofpclass(ninf) [[ARG0:%.*]]) #[[ATTR1]] {
-; CHECK-NEXT:    [[CALL:%.*]] = call float @llvm.exp.f32(float [[ARG0]]) #[[ATTR2]]
+; CHECK-NEXT:    [[CALL:%.*]] = call nofpclass(ninf nzero nsub nnorm) float @llvm.exp.f32(float [[ARG0]]) #[[ATTR2]]
 ; CHECK-NEXT:    ret float [[CALL]]
 ;
   %call = call float @llvm.exp.f32(float %arg0)
   ret float %call
 }
 
 define float @ret_exp_nonan(float nofpclass(nan) %arg0) {
-; CHECK-LABEL: define float @ret_exp_nonan
+; CHECK-LABEL: define nofpclass(nan ninf nzero nsub nnorm) 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 ninf nzero nsub nnorm) float @llvm.exp.f32(float [[ARG0]]) #[[ATTR2]]
 ; CHECK-NEXT:    ret float [[CALL]]
 ;
   %call = call float @llvm.exp.f32(float %arg0)
   ret float %call
 }
 
 define float @ret_exp_nonan_noinf(float nofpclass(nan inf) %arg0) {
-; CHECK-LABEL: define float @ret_exp_nonan_noinf
+; CHECK-LABEL: define nofpclass(nan ninf nzero nsub nnorm) 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 ninf nzero nsub nnorm) float @llvm.exp.f32(float [[ARG0]]) #[[ATTR2]]
 ; CHECK-NEXT:    ret float [[CALL]]
 ;
   %call = call float @llvm.exp.f32(float %arg0)
   ret float %call
 }
 
 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 ninf nzero nsub nnorm) 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 ninf nzero nsub nnorm) float @llvm.exp.f32(float [[ARG0]]) #[[ATTR2]]
 ; CHECK-NEXT:    ret float [[CALL]]
 ;
   %call = call float @llvm.exp.f32(float %arg0)
   ret float %call
 }
 
 define float @ret_exp_noinf_nozero(float nofpclass(inf zero) %arg0) {
-; CHECK-LABEL: define float @ret_exp_noinf_nozero
+; CHECK-LABEL: define nofpclass(ninf nzero nsub nnorm) float @ret_exp_noinf_nozero
 ; CHECK-SAME: (float nofpclass(inf zero) [[ARG0:%.*]]) #[[ATTR1]] {
-; CHECK-NEXT:    [[CALL:%.*]] = call float @llvm.exp.f32(float [[ARG0]]) #[[ATTR2]]
+; CHECK-NEXT:    [[CALL:%.*]] = call nofpclass(ninf nzero nsub nnorm) float @llvm.exp.f32(float [[ARG0]]) #[[ATTR2]]
 ; CHECK-NEXT:    ret float [[CALL]]
 ;
   %call = call float @llvm.exp.f32(float %arg0)
   ret float %call
 }
 
 define float @ret_exp_noinf_nonegzero(float nofpclass(inf nzero) %arg0) {
-; CHECK-LABEL: define float @ret_exp_noinf_nonegzero
+; CHECK-LABEL: define nofpclass(ninf nzero nsub nnorm) float @ret_exp_noinf_nonegzero
 ; CHECK-SAME: (float nofpclass(inf nzero) [[ARG0:%.*]]) #[[ATTR1]] {
-; CHECK-NEXT:    [[CALL:%.*]] = call float @llvm.exp.f32(float [[ARG0]]) #[[ATTR2]]
+; CHECK-NEXT:    [[CALL:%.*]] = call nofpclass(ninf nzero nsub nnorm) float @llvm.exp.f32(float [[ARG0]]) #[[ATTR2]]
 ; CHECK-NEXT:    ret float [[CALL]]
 ;
   %call = call float @llvm.exp.f32(float %arg0)
   ret float %call
 }
 
 define float @ret_exp_positive_source(i32 %arg) {
-; CHECK-LABEL: define float @ret_exp_positive_source
+; CHECK-LABEL: define nofpclass(nan ninf nzero nsub nnorm) 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 ninf nzero nsub nnorm) float @llvm.exp.f32(float [[UITOFP]]) #[[ATTR2]]
 ; CHECK-NEXT:    ret float [[CALL]]
 ;
   %uitofp = uitofp i32 %arg to float
   %call = call float @llvm.exp.f32(float %uitofp)
   ret float %call
 }
 
 ; 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 ninf nzero nsub nnorm) 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 ninf nzero nsub nnorm) float @llvm.exp.f32(float [[UNKNOWN_SIGN_NOT_NAN]]) #[[ATTR2]]
 ; CHECK-NEXT:    ret float [[CALL]]
 ;
   %unknown.sign.not.nan = fmul nnan float %arg0, %arg1
   %call = call float @llvm.exp.f32(float %unknown.sign.not.nan)
   ret float %call
 }
 
 define float @ret_exp2(float %arg0) {
-; CHECK-LABEL: define float @ret_exp2
+; CHECK-LABEL: define nofpclass(ninf nzero nsub nnorm) float @ret_exp2
 ; CHECK-SAME: (float [[ARG0:%.*]]) #[[ATTR1]] {
-; CHECK-NEXT:    [[CALL:%.*]] = call float @llvm.exp2.f32(float [[ARG0]]) #[[ATTR2]]
+; CHECK-NEXT:    [[CALL:%.*]] = call nofpclass(ninf nzero nsub nnorm) float @llvm.exp2.f32(float [[ARG0]]) #[[ATTR2]]
 ; CHECK-NEXT:    ret float [[CALL]]
 ;
   %call = call float @llvm.exp2.f32(float %arg0)
   ret float %call
 }
 
 define float @ret_exp2_noinf(float nofpclass(inf) %arg0) {
-; CHECK-LABEL: define float @ret_exp2_noinf
+; CHECK-LABEL: define nofpclass(ninf nzero nsub nnorm) float @ret_exp2_noinf
 ; CHECK-SAME: (float nofpclass(inf) [[ARG0:%.*]]) #[[ATTR1]] {
-; CHECK-NEXT:    [[CALL:%.*]] = call float @llvm.exp2.f32(float [[ARG0]]) #[[ATTR2]]
+; CHECK-NEXT:    [[CALL:%.*]] = call nofpclass(ninf nzero nsub nnorm) float @llvm.exp2.f32(float [[ARG0]]) #[[ATTR2]]
 ; CHECK-NEXT:    ret float [[CALL]]
 ;
   %call = call float @llvm.exp2.f32(float %arg0)
   ret float %call
 }
 
 define float @ret_exp2_nopinf(float nofpclass(pinf) %arg0) {
-; CHECK-LABEL: define float @ret_exp2_nopinf
+; CHECK-LABEL: define nofpclass(ninf nzero nsub nnorm) float @ret_exp2_nopinf
 ; CHECK-SAME: (float nofpclass(pinf) [[ARG0:%.*]]) #[[ATTR1]] {
-; CHECK-NEXT:    [[CALL:%.*]] = call float @llvm.exp2.f32(float [[ARG0]]) #[[ATTR2]]
+; CHECK-NEXT:    [[CALL:%.*]] = call nofpclass(ninf nzero nsub nnorm) float @llvm.exp2.f32(float [[ARG0]]) #[[ATTR2]]
 ; CHECK-NEXT:    ret float [[CALL]]
 ;
   %call = call float @llvm.exp2.f32(float %arg0)
   ret float %call
 }
 
 define float @ret_exp2_noninf(float nofpclass(ninf) %arg0) {
-; CHECK-LABEL: define float @ret_exp2_noninf
+; CHECK-LABEL: define nofpclass(ninf nzero nsub nnorm) float @ret_exp2_noninf
 ; CHECK-SAME: (float nofpclass(ninf) [[ARG0:%.*]]) #[[ATTR1]] {
-; CHECK-NEXT:    [[CALL:%.*]] = call float @llvm.exp2.f32(float [[ARG0]]) #[[ATTR2]]
+; CHECK-NEXT:    [[CALL:%.*]] = call nofpclass(ninf nzero nsub nnorm) float @llvm.exp2.f32(float [[ARG0]]) #[[ATTR2]]
 ; CHECK-NEXT:    ret float [[CALL]]
 ;
   %call = call float @llvm.exp2.f32(float %arg0)
   ret float %call
 }
 
 define float @ret_exp2_nonan(float nofpclass(nan) %arg0) {
-; CHECK-LABEL: define float @ret_exp2_nonan
+; CHECK-LABEL: define nofpclass(nan ninf nzero nsub nnorm) 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 ninf nzero nsub nnorm) float @llvm.exp2.f32(float [[ARG0]]) #[[ATTR2]]
 ; CHECK-NEXT:    ret float [[CALL]]
 ;
   %call = call float @llvm.exp2.f32(float %arg0)
   ret float %call
 }
 
 define float @ret_exp2_nonan_noinf(float nofpclass(nan inf) %arg0) {
-; CHECK-LABEL: define float @ret_exp2_nonan_noinf
+; CHECK-LABEL: define nofpclass(nan ninf nzero nsub nnorm) 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 ninf nzero nsub nnorm) float @llvm.exp2.f32(float [[ARG0]]) #[[ATTR2]]
 ; CHECK-NEXT:    ret float [[CALL]]
 ;
   %call = call float @llvm.exp2.f32(float %arg0)
   ret float %call
 }
 
 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 ninf nzero nsub nnorm) 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 ninf nzero nsub nnorm) float @llvm.exp2.f32(float [[ARG0]]) #[[ATTR2]]
 ; CHECK-NEXT:    ret float [[CALL]]
 ;
   %call = call float @llvm.exp2.f32(float %arg0)
   ret float %call
 }
 
 define float @ret_exp2_noinf_nozero(float nofpclass(inf zero) %arg0) {
-; CHECK-LABEL: define float @ret_exp2_noinf_nozero
+; CHECK-LABEL: define nofpclass(ninf nzero nsub nnorm) float @ret_exp2_noinf_nozero
 ; CHECK-SAME: (float nofpclass(inf zero) [[ARG0:%.*]]) #[[ATTR1]] {
-; CHECK-NEXT:    [[CALL:%.*]] = call float @llvm.exp2.f32(float [[ARG0]]) #[[ATTR2]]
+; CHECK-NEXT:    [[CALL:%.*]] = call nofpclass(ninf nzero nsub nnorm) float @llvm.exp2.f32(float [[ARG0]]) #[[ATTR2]]
 ; CHECK-NEXT:    ret float [[CALL]]
 ;
   %call = call float @llvm.exp2.f32(float %arg0)
   ret float %call
 }
 
 define float @ret_exp2_noinf_nonegzero(float nofpclass(inf nzero) %arg0) {
-; CHECK-LABEL: define float @ret_exp2_noinf_nonegzero
+; CHECK-LABEL: define nofpclass(ninf nzero nsub nnorm) float @ret_exp2_noinf_nonegzero
 ; CHECK-SAME: (float nofpclass(inf nzero) [[ARG0:%.*]]) #[[ATTR1]] {
-; CHECK-NEXT:    [[CALL:%.*]] = call float @llvm.exp2.f32(float [[ARG0]]) #[[ATTR2]]
+; CHECK-NEXT:    [[CALL:%.*]] = call nofpclass(ninf nzero nsub nnorm) float @llvm.exp2.f32(float [[ARG0]]) #[[ATTR2]]
 ; CHECK-NEXT:    ret float [[CALL]]
 ;
   %call = call float @llvm.exp2.f32(float %arg0)
   ret float %call
 }
 
 define float @ret_exp2_positive_source(i32 %arg) {
-; CHECK-LABEL: define float @ret_exp2_positive_source
+; CHECK-LABEL: define nofpclass(nan ninf nzero nsub nnorm) 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 ninf nzero nsub nnorm) float @llvm.exp2.f32(float [[UITOFP]]) #[[ATTR2]]
 ; CHECK-NEXT:    ret float [[CALL]]
 ;
   %uitofp = uitofp i32 %arg to float
   %call = call float @llvm.exp2.f32(float %uitofp)
   ret float %call
 }
 
 ; 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 ninf nzero nsub nnorm) 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 ninf nzero nsub nnorm) float @llvm.exp2.f32(float [[UNKNOWN_SIGN_NOT_NAN]]) #[[ATTR2]]
 ; CHECK-NEXT:    ret float [[CALL]]
 ;
   %unknown.sign.not.nan = fmul nnan float %arg0, %arg1
   %call = call float @llvm.exp2.f32(float %unknown.sign.not.nan)
   ret float %call
 }