From: Christophe Leroy <christophe.leroy@c-s.fr>
Date: Tue, 22 Sep 2015 14:34:34 +0000 (+0200)
Subject: powerpc: simplify csum_add(a, b) in case a or b is constant 0
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=5a8847c83ce6072d6fdf0d15d9aa060c0b83537f;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git

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 1778f75bf769..74cd8d82628a 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