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| author |   Christophe Leroy <christophe.leroy@csgroup.eu> | 2022-02-12 08:36:17 +0100 |
|---|---|---|
| committer |   Michael Ellerman <mpe@ellerman.id.au> | 2022-05-06 00:00:20 +1000 |
| commit | f206fdd9d41bf7deb96219b8ca3499a5abd79b83 (patch) | |
| tree | c1ac749778f42033eb99894a1fb3c7803e6b69cb /arch/powerpc/include/asm/checksum.h | |
| parent | powerpc/64: remove system call instruction emulation (diff) | |
| download | linux-dev-f206fdd9d41bf7deb96219b8ca3499a5abd79b83.tar.xz linux-dev-f206fdd9d41bf7deb96219b8ca3499a5abd79b83.zip | |
powerpc: Reduce csum_add() complexity for PPC64
PPC64 does everything in C, gcc is able to skip calculation
when one of the operands in zero.
Move the constant folding in PPC32 part.
This helps GCC and reduces ppc64_defconfig by 170 bytes.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/a4ca63dd4c4b09e1906d08fb814af5a41d0f3fcb.1644651363.git.christophe.leroy@csgroup.eu
Diffstat (limited to '')
| -rw-r--r-- | arch/powerpc/include/asm/checksum.h | 9 |
1 files changed, 4 insertions, 5 deletions
diff --git a/arch/powerpc/include/asm/checksum.h b/arch/powerpc/include/asm/checksum.h index ab3832b93f0a..8321f6053a67 100644 --- a/arch/powerpc/include/asm/checksum.h +++ b/arch/powerpc/include/asm/checksum.h @@ -95,16 +95,15 @@ static __always_inline __wsum csum_add(__wsum csum, __wsum addend) { #ifdef __powerpc64__ u64 res = (__force u64)csum; -#endif + + res += (__force u64)addend; + return (__force __wsum)((u32)res + (res >> 32)); +#else 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 asm("addc %0,%0,%1;" "addze %0,%0;" : "+r" (csum) : "r" (addend) : "xer"); |