fix exp(weirdNaN)
#56784
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fix exp(weirdNaN)
#56784
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Fix `exp(reinterpret(Float64, 0x7ffbb14880000000))` returning non-NaN value. This should have minimal performance impact since it's already in the fallback branch.
oscardssmith
added
maths
|
FYI, the "weird" NaN is just a NaN with a different bitpattern than our usual one: julia> reinterpret(Float64, 0x7ffbb14880000000) |> exp
-9.627794635514914e-309
julia> NaN |> bitstring
"0111111111111000000000000000000000000000000000000000000000000000"
julia> reinterpret(Float64, 0x7ffbb14880000000) |> bitstring
"0111111111111011101100010100100010000000000000000000000000000000"so a slightly "cleaner" pattern can also serve as a reproducer, as long as the bitpattern is distinct from the usual one: julia> @check db=false (f=Data.Floats{Float64}()) -> begin
uint_float = reinterpret(UInt, f)
event!(uint_float)
event!(bitstring(uint_float))
res = exp(f)
isnan(res) == isnan(f) || res >= 0
end
Found counterexample
Context: ##SuppositionAnon#334
Arguments:
f::Float64 = NaN
Events:
UNLABELED_EVENT_0
0x7ff0000000000100
UNLABELED_EVENT_1
"0111111111110000000000000000000000000000000000000000000100000000"All of these are proper |
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Fixes #56782
Fix
exp(reinterpret(Float64, 0x7ffbb14880000000))returning non-NaN value. This should have minimal performance impact since it's already in the fallback branch.