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[flang] Don't force SET_EXPONENT(I=...) argument to integer(4) 

The implementation of the folding code for SET_EXPONENT() was written
in such a fashion as to convert the I= actual argument value to a 32-bit
integer.  Which is usually not a problem, but it's not always correct
and a test case ran into trouble with it.  Fix to allow any kind of
INTEGER without conversion.

Differential Revision: https://reviews.llvm.org/D135203
This commit is contained in:
Peter Klausler 2022-10-04 10:17:04 -07:00
parent eac3e5c3fb
commit 8100374437
3 changed files with 24 additions and 13 deletions
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16
flang/include/flang/Evaluate/real.h
View File

@ -170,7 +170,7 @@ public:
static constexpr int MINEXPONENT{2 - exponentBias};
Real RRSPACING() const;
Real SPACING() const;
Real SET_EXPONENT(int) const;
Real SET_EXPONENT(std::int64_t) const;
Real FRACTION() const;
// SCALE(); also known as IEEE_SCALB and (in IEEE-754 '08) ScaleB.
@ -182,16 +182,20 @@ public:
// be subnormal.)
auto adjust{exponentBias + binaryPrecision - 1};
auto expo{adjust + by.ToInt64()};
Real twoPow;
RealFlags flags;
int rMask{1};
if (IsZero()) {
expo = exponentBias; // ignore by, don't overflow
} else if (by > INT{maxExponent}) {
expo = maxExponent + binaryPrecision - 1;
} else if (by < INT{-adjust}) {
expo = -1;
} else if (by < INT{-adjust}) { // underflow
expo = 0;
rMask = 0;
flags.set(RealFlag::Underflow);
}
Real twoPow;
RealFlags flags{
twoPow.Normalize(false, static_cast<int>(expo), Fraction::MASKR(1))};
flags |=
twoPow.Normalize(false, static_cast<int>(expo), Fraction::MASKR(rMask));
ValueWithRealFlags<Real> result{Multiply(twoPow, rounding)};
result.flags |= flags;
return result;

17
flang/lib/Evaluate/fold-real.cpp
View File

@ -257,11 +257,18 @@ Expr<Type<TypeCategory::Real, KIND>> FoldIntrinsicFunction(
byExpr->u);
}
} else if (name == "set_exponent") {
return FoldElementalIntrinsic<T, T, Int4>(context, std::move(funcRef),
ScalarFunc<T, T, Int4>(
[&](const Scalar<T> &x, const Scalar<Int4> &i) -> Scalar<T> {
return x.SET_EXPONENT(i.ToInt64());
}));
if (const auto *iExpr{UnwrapExpr<Expr<SomeInteger>>(args[1])}) {
return common::visit(
[&](const auto &iVal) {
using TY = ResultType<decltype(iVal)>;
return FoldElementalIntrinsic<T, T, TY>(context, std::move(funcRef),
ScalarFunc<T, T, TY>(
[&](const Scalar<T> &x, const Scalar<TY> &i) -> Scalar<T> {
return x.SET_EXPONENT(i.ToInt64());
}));
},
iExpr->u);
}
} else if (name == "sign") {
return FoldElementalIntrinsic<T, T, T>(
context, std::move(funcRef), &Scalar<T>::SIGN);

4
flang/lib/Evaluate/real.cpp
View File

@ -756,7 +756,7 @@ template <typename W, int P> Real<W, P> Real<W, P>::SPACING() const {
// 16.9.171
template <typename W, int P>
Real<W, P> Real<W, P>::SET_EXPONENT(int expo) const {
Real<W, P> Real<W, P>::SET_EXPONENT(std::int64_t expo) const {
if (IsNotANumber()) {
return *this;
} else if (IsInfinite()) {
@ -764,7 +764,7 @@ Real<W, P> Real<W, P>::SET_EXPONENT(int expo) const {
} else if (IsZero()) {
return *this;
} else {
return SCALE(Integer<32>(expo - UnbiasedExponent() - 1)).value;
return SCALE(Integer<64>(expo - UnbiasedExponent() - 1)).value;
}
}