[PATCH 0/4] powerpc: Replace some bitops functions by builtin/generic ones

From: Christophe Leroy
Date: Fri Apr 21 2017 - 07:18:52 EST


This patchset replaces the following bitops by builtin/generic ones:
- ffs() / __ffs()
- fls() / __fls() / fls64()
- ffz()
- __ilog2() / __ilog2_u32() / __ilog2_u64()

The current functions are written as inline assembly which prevents
GCC to optimise them in case of constant parameters and obliges GCC
to group the related instructions all together.

With the builtin alternatives, GCC optimises better

Christophe Leroy (4):
powerpc: Discard ffs()/__ffs() function and use builtin functions
instead
powerpc: Use builtin functions for fls()/__fls()/fls64()
powerpc: Replace ffz() by equivalent generic function
powerpc: remove __ilog2()s and use generic ones

arch/powerpc/Kconfig | 8 ----
arch/powerpc/include/asm/bitops.h | 87 ++++-----------------------------------
2 files changed, 7 insertions(+), 88 deletions(-)

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2.12.0