Commit dfda65c8 authored by Noah Goldstein's avatar Noah Goldstein
Browse files

[ValueTracking] Add support for non-splat vecs in cmpExcludesZero 

Just a small QOL change.
parent 9427fce6

llvm/lib/Analysis/ValueTracking.cpp

+16 −3
Original line number Diff line number Diff line
@@ -567,11 +567,24 @@ static bool cmpExcludesZero(CmpInst::Predicate Pred, const Value *RHS) { 


  // All other predicates - rely on generic ConstantRange handling.

  const APInt *C;

  if (!match(RHS, m_APInt(C)))

  auto Zero = APInt::getZero(RHS->getType()->getScalarSizeInBits());

  if (match(RHS, m_APInt(C))) {

    ConstantRange TrueValues = ConstantRange::makeExactICmpRegion(Pred, *C);

    return !TrueValues.contains(Zero);

  }



  auto *VC = dyn_cast<ConstantDataVector>(RHS);

  if (VC == nullptr)

    return false;



  ConstantRange TrueValues = ConstantRange::makeExactICmpRegion(Pred, *C);

  return !TrueValues.contains(APInt::getZero(C->getBitWidth()));

  for (unsigned ElemIdx = 0, NElem = VC->getNumElements(); ElemIdx < NElem;

       ++ElemIdx) {

    ConstantRange TrueValues = ConstantRange::makeExactICmpRegion(

        Pred, VC->getElementAsAPInt(ElemIdx));

    if (TrueValues.contains(Zero))

      return false;

  }

  return true;

}



static bool isKnownNonZeroFromAssume(const Value *V, const SimplifyQuery &Q) {

llvm/test/Analysis/ValueTracking/known-non-zero.ll

+1 −5
Original line number Diff line number Diff line
@@ -1163,11 +1163,7 @@ define i1 @sdiv_known_non_zero_fail(i8 %x, i8 %y) { 


define <2 x i1> @cmp_excludes_zero_with_nonsplat_vec(<2 x i8> %a, <2 x i8> %b) {

; CHECK-LABEL: @cmp_excludes_zero_with_nonsplat_vec(

; CHECK-NEXT:    [[C:%.*]] = icmp sge <2 x i8> [[A:%.*]], <i8 1, i8 4>

; CHECK-NEXT:    [[S:%.*]] = select <2 x i1> [[C]], <2 x i8> [[A]], <2 x i8> <i8 4, i8 5>

; CHECK-NEXT:    [[AND:%.*]] = or <2 x i8> [[S]], [[B:%.*]]

; CHECK-NEXT:    [[R:%.*]] = icmp eq <2 x i8> [[AND]], zeroinitializer

; CHECK-NEXT:    ret <2 x i1> [[R]]

; CHECK-NEXT:    ret <2 x i1> zeroinitializer

;

  %c = icmp sge <2 x i8> %a, <i8 1, i8 4>

  %s = select <2 x i1> %c, <2 x i8> %a, <2 x i8> <i8 4, i8 5>