Simplify csum_add(a, b) in case a or b is constant 0
Signed-off-by: Christophe Leroy <redacted>
---
arch/powerpc/include/asm/checksum.h | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/arch/powerpc/include/asm/checksum.h b/arch/powerpc/include/asm/checksum.h
index 56deea8..f8a9704 100644
--- a/arch/powerpc/include/asm/checksum.h
+++ b/arch/powerpc/include/asm/checksum.h
@@ -119,7 +119,13 @@ static inline __wsum csum_add(__wsum csum, __wsum addend)
{
#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--
2.1.0