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author | Christian Borntraeger <borntraeger@de.ibm.com> | 2015-10-29 01:16:04 +0100 |
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committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2015-11-03 14:40:48 +0100 |
commit | 295d8fa961466bb9e9ebb87b46fdad4edaf736de (patch) | |
tree | e4a50c47b5520c119bc4bce0f8329057ad707858 /drivers/s390 | |
parent | ccc0e7dc708ce1bd2e1c4a2b6a180ae7459374de (diff) | |
download | op-kernel-dev-295d8fa961466bb9e9ebb87b46fdad4edaf736de.zip op-kernel-dev-295d8fa961466bb9e9ebb87b46fdad4edaf736de.tar.gz |
s390/Kconfig: use builtin bswap
Depending on the gcc version we can use builtin_bswap instead of
architecture functions. Doing so is better than the inline assembly
version of load reverse for two reasons:
- the sequence of load reversed, apply constant mask, save reversed can
be optimized to load, apply reversed mask, save
- builtins are slightly better to optimize e.g. gcc instruction
scheduler cannot optimize grouping on inline assemblies.
To enable set we have to ARCH_USE_BUILTIN_BSWAP.
bloat-o-meter results:
add/remove: 1/1 grow/shrink: 75/533 up/down: 1711/-9394 (-7683)
Suggested-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'drivers/s390')
0 files changed, 0 insertions, 0 deletions