Marco Bodrato <bodr...@mail.dm.unipi.it> writes:
From our testing system is emerging an error on some powerpc750.
The test t-cmp_d for mini-gmp is failing with:
mpz_cmp_d wrong (from check_infinity)
got 1
want -1
x=141246703213942603[...]
[...]
y 3.40282e+38
y 47 F0 00 00 00 00 00 00
This comes from the following lines in mini-gmp/tests/t-cmp_d.c:
void
check_infinity (void)
{
mpz_t x;
double y = HUGE_VAL;
if (y != 2*y)
return;
[..]
/* 2^5000 cmp inf */
mpz_set_ui (x, 1L);
mpz_mul_2exp (x, x, 5000L);
check_one ("check_infinity", x, y, -1, -1);
[..]
So, it seems that on that systems HUGE_VAL is defined as 3.40282e+38.
This probably is the larger value that can be represented, because the
function does not stop the test after the "if (y != 2*y) return;"
check.
But in the function cmp_d, the double value is not multiplied, it is
divided... maybe if we change the initial test into "if (y != y/2)
return;", then the test is simply skipped in this case. May this be
the desired behaviour?
These systems run behind ashell under qemu, on a new 12-core Ryzen
3900X. You can test there.
We often run into qemu bugs, and this might be another example. It
might be possible to find a version of qemu which runs the present
binaries correctly.
I will link lots of qemu versions under /usr/bin/qemu/VERSION when I
have the time to modify my scripts. Thereby, it is possible to manually
run a binary under a different qemu version.
--
Torbjörn
Please encrypt, key id 0xC8601622
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