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Fix comparison of decimal float zeroes (PR80692)

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Decimal float negative zero should compare equal to positive zero.
Decimal float zeroes are encoded as value class "normal" (in real.c);
they need to be handled specially, but in this one case that does not
yet happen.  This fixes it.


	PR middle-end/80692
	* real.c (do_compare): Give decimal_do_compare preference over
	comparing just the signs.

gcc/testsuite/
	PR middle-end/80692
	* gcc.c-torture/execute/pr80692.c: New testcase.

From-SVN: r248174
This commit is contained in:
Segher Boessenkool 2017-05-17 23:57:23 +02:00 • committed by Segher Boessenkool
parent 78eca3093f
commit e98e63404c
4 changed files with 27 additions and 3 deletions
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6
gcc/ChangeLog
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@ -1,3 +1,9 @@
2017-05-17 Segher Boessenkool <segher@kernel.crashing.org>
PR middle-end/80692
* real.c (do_compare): Give decimal_do_compare preference over
comparing just the signs.
2017-05-17 Uros Bizjak <ubizjak@gmail.com>
* doc/md.texi (Canonicalization of Instructions): Describe the

6
gcc/real.c
View file

@ -960,12 +960,12 @@ do_compare (const REAL_VALUE_TYPE *a, const REAL_VALUE_TYPE *b,
gcc_unreachable ();
}
if (a->sign != b->sign)
return -a->sign - -b->sign;
if (a->decimal || b->decimal)
return decimal_do_compare (a, b, nan_result);
if (a->sign != b->sign)
return -a->sign - -b->sign;
if (REAL_EXP (a) > REAL_EXP (b))
ret = 1;
else if (REAL_EXP (a) < REAL_EXP (b))

5
gcc/testsuite/ChangeLog
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@ -1,3 +1,8 @@
2017-05-17 Segher Boessenkool <segher@kernel.crashing.org>
PR middle-end/80692
* gcc.c-torture/execute/pr80692.c: New testcase.
2017-05-17 Jerry DeLisle <jvdelisle@gcc.gnu.org>
PR libgfortran/80741

13
gcc/testsuite/gcc.c-torture/execute/pr80692.c Normal file
View file

@ -0,0 +1,13 @@
/* { dg-require-effective-target dfp } */
int main () {
_Decimal64 d64 = -0.DD;
if (d64 != 0.DD)
__builtin_abort ();
if (d64 != -0.DD)
__builtin_abort ();
return 0;
}