This series allows the simplification of expressions like:
if (val1 & 4)
val2 |= 8;
into
val2 |= (val1 & 4) << 1;
With a better if-conversion mechanism it also allows to optimize
int translate_bits(int x)
{
int y = 0;
if (x & 4)
y |= 16;
if (x & 8)
y |= 32;
return y;
}
into this nice:
translate_bits:
and.32 %r2 <- %arg1, $12
shl.32 %r5 <- %r2, $2
ret.32 %r5
when applied on top of the previous 'factorization' series.
This series is available for review and testing at:
git://git.kernel.org/pub/scm/devel/sparse/sparse-dev.git bit-trans
Luc Van Oostenryck (6):
add testscases for 'bits translation' optimization
factorize SEL(x, OP(y,z), y) into OP(SEL(x, z, 0), y)
add helper is_power_of_2()
add helper is_pow2()
add log base 2 function: log2_exact()
convert SEL(x & BIT1, BIT2, 0) into SHIFT(x & BIT1, S)
bits.h | 12 ++++++
simplify.c | 64 +++++++++++++++++++++++++++++
validation/optim/fact-select01.c | 25 +++++++++++
validation/optim/select-and-shift.c | 17 ++++++++
4 files changed, 118 insertions(+)
create mode 100644 validation/optim/fact-select01.c
create mode 100644 validation/optim/select-and-shift.c
--
2.29.2
