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New FASTER_BIGNUM macro to test slow-path code

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* src/bignum.h (FASTER_BIGNUM): New macro.
(mpz_set_intmax, mpz_set_uintmax): Optimize only if FASTER_BIGNUM.
Also, use ckd_add to test for overflow instead of doing it by hand.
This commit is contained in:
Paul Eggert 2024-07-11 12:27:36 +02:00
parent 2fb7bb41be
commit 1c8e64a953
1 changed files with 12 additions and 4 deletions
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16
src/bignum.h
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@ -25,6 +25,12 @@ along with GNU Emacs. If not, see <https://www.gnu.org/licenses/>. */
#include <gmp.h>
#include "lisp.h"
/* Compile with -DFASTER_BIGNUM=0 to disable common optimizations and
allow easier testing of some slow-path code. */
#ifndef FASTER_BIGNUM
# define FASTER_BIGNUM 1
#endif
/* Number of data bits in a limb. */
#ifndef GMP_NUMB_BITS
enum { GMP_NUMB_BITS = TYPE_WIDTH (mp_limb_t) };
@ -68,16 +74,18 @@ mpz_set_intmax (mpz_t result, intmax_t v)
/* mpz_set_si works in terms of long, but Emacs may use a wider
integer type, and so sometimes will have to construct the mpz_t
by hand. */
if (LONG_MIN <= v && v <= LONG_MAX)
mpz_set_si (result, v);
long int i;
if (FASTER_BIGNUM && !ckd_add (&i, v, 0))
mpz_set_si (result, i);
else
mpz_set_intmax_slow (result, v);
}
INLINE void ARG_NONNULL ((1))
mpz_set_uintmax (mpz_t result, uintmax_t v)
{
if (v <= ULONG_MAX)
mpz_set_ui (result, v);
unsigned long int i;
if (FASTER_BIGNUM && !ckd_add (&i, v, 0))
mpz_set_ui (result, i);
else
mpz_set_uintmax_slow (result, v);
}