# [git commit] factor: factor2 variable is unused now, drop it

Sun Apr 9 21:19:47 UTC 2017

```commit: https://git.busybox.net/busybox/commit/?id=c804d4ec5cb222c842644bb99d9b077f5c6576f2

Signed-off-by: Denys Vlasenko <vda.linux at googlemail.com>
---
coreutils/factor.c | 6 ------
1 file changed, 6 deletions(-)

diff --git a/coreutils/factor.c b/coreutils/factor.c
index 1c01e3f..85284aa 100644
--- a/coreutils/factor.c
+++ b/coreutils/factor.c
@@ -89,7 +89,6 @@ static NOINLINE half_t isqrt_odd(wide_t N)

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