Hi,
I found a bug when running some tests under Valgrind. The mpz_invert
function gives wrong results if its arguments are larger than 64 bits.
GMP version: 6.1.2
Valgrind version: 3.13.0
GCC: gcc version 5.5.0 20171010 (Ubuntu 5.5.0-12ubuntu1~16.04)
Kernel: Linux xlab-jan 4.4.0-128-generic #154-Ubuntu SMP Fri May 25
14:15:18 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux
Architecture: skylake-pc-linux-gnu
Code for reproducing: attached (Compile it with /gcc -o g gmp_valgrind.c
-lgmp/ and run with /./g/ and /valgrind ./g/, when run normally it
should output equal = 1 and under Valgrind equal = 0)
I know it's stated in the GMP Manual that Valgrind might not support
instructions recently added to an ISA, but this seems like it should
work. I hope I provided enough details to verify and reproduce this.
Best regards,
Jan
#include <gmp.h>
int main() {
mpz_t g, p, z, i;
mpz_inits(g, p, z, i, NULL);
mpz_set_str(g, "164917514854091185926007547162250134788", 10);
mpz_set_str(p, "297610433467095548694109139968310730599", 10);
mpz_set_str(i, "227530644042031236994570943278081104642", 10);
mpz_invert(z, g, p);
gmp_printf("true inverse = %Zd\ncalculated inverse = %Zd\nequal = %d\n", i, z, !mpz_cmp(i, z));
mpz_clears(g, p, z, i, NULL);
return 0;
}
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