[PATCH 2/2] MPILIB: Deobfuscate mpi_cmp

Rasmus Villemoes
2014-12-06T00:01:04Z

The condition preceding 'return 1;' makes my head hurt. At this point,
we know that u and v have the same sign; if they are negative, they
compare opposite to how their absolute values compare (which
mpihelp_cmp found for us), otherwise cmp itself is the
answer. Negating cmp is ok since mpihelp_cmp returns {-1,0,1};
-INT_MIN==INT_MIN won't bite us.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
---
lib/mpi/mpi-cmp.c | 8 +++-----
1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/lib/mpi/mpi-cmp.c b/lib/mpi/mpi-cmp.c
index 3801694240d8..d25e9e96c310 100644
--- a/lib/mpi/mpi-cmp.c
+++ b/lib/mpi/mpi-cmp.c
@@ -61,10 +61,8 @@ int mpi_cmp(MPI u, MPI v)
if (!usize)
return 0;
cmp = mpihelp_cmp(u->d, v->d, usize);
- if (!cmp)
- return 0;
- if ((cmp < 0 ? 1 : 0) == (u->sign ? 1 : 0))
- return 1;
- return -1;
+ if (u->sign)
+ return -cmp;
+ return cmp;
}
EXPORT_SYMBOL_GPL(mpi_cmp);
--
2.1.3