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2bcdf28084
tests/hard_coded/write_float_special.m:
Make it harder for a C compiler to incorrectly "optimise"
Inf * 0.0 to 0.0 instead of NaN.
Seen with gcc version 5.4.0 20160609 (Ubuntu 5.4.0-6ubuntu1~16.04.9)
i686 at -O1 and above.
40 lines
1.1 KiB
Mathematica
40 lines
1.1 KiB
Mathematica
%---------------------------------------------------------------------------%
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% vim: ft=mercury ts=4 sw=4 et
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%---------------------------------------------------------------------------%
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%
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% Regression test for problems with io.write_float handling special float
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% values. In Mercury 14.01 and before ".0" was appended to the string printed
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% for special float values, for example:
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%
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% io.write_float(nan, !IO) ==> "nan.0"
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%
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%---------------------------------------------------------------------------%
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:- module write_float_special.
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:- interface.
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:- import_module io.
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:- pred main(io::di, io::uo) is det.
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:- implementation.
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:- import_module float.
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:- import_module list.
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:- import_module string.
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main(!IO) :-
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Inf = float.max + float.max,
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NegInf = -Inf,
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% Avoid C compiler incorrectly optimising Inf * 0.0 to 0.0.
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Zero = float(length([] : list(float))),
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NaN = Inf * Zero,
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io.write_string("Inf: ", !IO),
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io.write_float(Inf, !IO),
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io.nl(!IO),
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io.write_string("-Inf: ", !IO),
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io.write_float(NegInf, !IO),
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io.nl(!IO),
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io.write_string("NaN: ", !IO),
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io.write_float(NaN, !IO),
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io.nl(!IO).
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