powerpc: simplify csum_add(a, b) in case a or b is constant 0
Simplify csum_add(a, b) in case a or b is constant 0
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Scott Wood <oss@buserror.net>
diff --git a/arch/powerpc/include/asm/checksum.h b/arch/powerpc/include/asm/checksum.h
index 1778f75..74cd8d8 100644
--- a/arch/powerpc/include/asm/checksum.h
+++ b/arch/powerpc/include/asm/checksum.h
@@ -119,7 +119,13 @@
{
#ifdef __powerpc64__
u64 res = (__force u64)csum;
+#endif
+ if (__builtin_constant_p(csum) && csum == 0)
+ return addend;
+ if (__builtin_constant_p(addend) && addend == 0)
+ return csum;
+#ifdef __powerpc64__
res += (__force u64)addend;
return (__force __wsum)((u32)res + (res >> 32));
#else