emo/busybox
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

factor: factor2 variable is unused now, drop it

Browse Source 
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2017-04-09 23:19:47 +02:00
parent 7e5f2f3b51
commit c804d4ec5c
1 changed files with 0 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
coreutils/factor.c
View File

@ -89,7 +89,6 @@ static NOINLINE half_t isqrt_odd(wide_t N)
static NOINLINE void factorize(wide_t N) static NOINLINE void factorize(wide_t N)
{ {
wide_t factor2;
half_t factor; half_t factor;
half_t max_factor; half_t max_factor;
unsigned count3; unsigned count3;
@ -105,7 +104,6 @@ static NOINLINE void factorize(wide_t N)
max_factor = isqrt_odd(N); max_factor = isqrt_odd(N);
count3 = 3; count3 = 3;
factor = 3; factor = 3;
factor2 = 3 * 3;
for (;;) { for (;;) {
/* The division is the most costly part of the loop. /* The division is the most costly part of the loop.
* On 64bit CPUs, takes at best 12 cycles, often ~20. * On 64bit CPUs, takes at best 12 cycles, often ~20.
@ -118,10 +116,6 @@ static NOINLINE void factorize(wide_t N)
next_factor: next_factor:
if (factor >= max_factor) if (factor >= max_factor)
break; break;
/* (f + 2)^2 = f^2 + 4*f + 4 = f^2 + 4*(f+1) */
factor2 = factor2 + 4 * (factor + 1);
/* overflow is impossible due to max_factor check */
/* (factor2 > N) is impossible due to max_factor check */
factor += 2; factor += 2;
/* Rudimentary wheel sieving: skip multiples of 3: /* Rudimentary wheel sieving: skip multiples of 3:
* Every third odd number is divisible by three and thus isn't a prime: * Every third odd number is divisible by three and thus isn't a prime: