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py/mpz: Remove unreachable code in mpn_or_neg functions.

This commit is contained in:
Damien George 2016-12-14 10:39:41 +11:00
parent 9112b0b62b
commit e83f140463
1 changed files with 9 additions and 6 deletions
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15
py/mpz.c
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@ -308,9 +308,13 @@ STATIC mp_uint_t mpn_or_neg(mpz_dig_t *idig, const mpz_dig_t *jdig, mp_uint_t jl
carryi >>= DIG_SIZE;
}
if (0 != carryi) {
*idig++ = carryi;
}
// At least one of j,k must be negative so the above for-loop runs at least
// once. For carryi to be non-zero here it must be equal to 1 at the end of
// each iteration of the loop. So the accumulation of carryi must overflow
// each time, ie carryi += 0xff..ff. So carryj|carryk must be 0 in the
// DIG_MASK bits on each iteration. But considering all cases of signs of
// j,k one sees that this is not possible.
assert(carryi == 0);
return mpn_remove_trailing_zeros(oidig, idig);
}
@ -334,9 +338,8 @@ STATIC mp_uint_t mpn_or_neg(mpz_dig_t *idig, const mpz_dig_t *jdig, mp_uint_t jl
carryi >>= DIG_SIZE;
}
if (0 != carryi) {
*idig++ = carryi;
}
// See comment in above mpn_or_neg for why carryi must be 0.
assert(carryi == 0);
return mpn_remove_trailing_zeros(oidig, idig);
}