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[flang] Warn on invalid argument to SQRT() #168607

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Merged
merged 1 commit into from
Dec 1, 2025
Merged

[flang] Warn on invalid argument to SQRT() #168607

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10 changes: 8 additions & 2 deletions flang/lib/Evaluate/fold-real.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -425,8 +425,14 @@ Expr<Type<TypeCategory::Real, KIND>> FoldIntrinsicFunction(
[](const Scalar<T> &x) -> Scalar<T> { return x.SPACING(); }));
} else if (name == "sqrt") {
return FoldElementalIntrinsic<T, T>(context, std::move(funcRef),
ScalarFunc<T, T>(
[](const Scalar<T> &x) -> Scalar<T> { return x.SQRT().value; }));
ScalarFunc<T, T>([&context](const Scalar<T> &x) -> Scalar<T> {
ValueWithRealFlags<Scalar<T>> result{x.SQRT()};
if (result.flags.test(RealFlag::InvalidArgument)) {
context.Warn(common::UsageWarning::FoldingValueChecks,
"Invalid argument to SQRT()"_warn_en_US);
}
return result.value;
}));
} else if (name == "sum") {
return FoldSum<T>(context, std::move(funcRef));
} else if (name == "tiny") {
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4 changes: 4 additions & 0 deletions flang/test/Evaluate/folding03.f90
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Expand Up @@ -83,6 +83,8 @@ module real_tests
real(4), parameter :: r4_pinf = 1._4/0._4
!WARN: warning: division by zero [-Wfolding-exception]
real(4), parameter :: r4_ninf = -1._4/0._4
!WARN: warning: Invalid argument to SQRT() [-Wfolding-value-checks]
real(4), parameter :: r4_sqrtneg = sqrt(-1._4)

logical, parameter :: test_r4_nan_parentheses1 = .NOT.(((r4_nan)).EQ.r4_nan)
logical, parameter :: test_r4_nan_parentheses2 = .NOT.(((r4_nan)).LT.r4_nan)
Expand Down Expand Up @@ -155,6 +157,8 @@ module real_tests
TEST_ISNAN(r4_nan_add5)
real(4), parameter :: r4_nan_add6 = r4_nan + r4_nan
TEST_ISNAN(r4_nan_add6)
real(4), parameter :: r4_nan_sqrt = sqrt(r4_nan)
TEST_ISNAN(r4_nan_sqrt)

!WARN: warning: overflow on multiplication [-Wfolding-exception]
logical, parameter :: test_inf_r4_mult1 = (1.5_4*r4_pmax).eq.(r4_pinf)
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