Remove some unnecessary optimizations in popcount code.
Over the past few releases, we've added a huge amount of complexity
to our popcount implementations. Commits fbe327e5b4, 79e232ca01,
8c6653516c, and 25dc485074 did some preliminary refactoring, but
many opportunities remain. In particular, if we disclaim interest
in micro-optimizing this code for 32-bit builds and in unnecessary
alignment checks on x86-64, we can remove a decent chunk of code.
I cannot find public discussion or benchmarks for the code this
commit removes, but it seems unlikely that this change will
noticeably impact performance on affected systems.
Suggested-by: John Naylor <johncnaylorls@gmail.com>
Reviewed-by: John Naylor <johncnaylorls@gmail.com>
Discussion: https://postgr.es/m/CANWCAZY7R%2Biy%2Br9YM_sySNydHzNqUirx1xk0tB3ej5HO62GdgQ%40mail.gmail.com
Branch
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master
Details
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https://git.postgresql.org/pg/commitdiff/cb7b2e5e8efb3e5fb08052425cd00f067a56f877
Modified Files
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src/include/port/pg_bitutils.h | 16 ++--------
src/port/pg_bitutils.c | 30 -------------------
src/port/pg_popcount_x86.c | 67 ++++++++----------------------------------
3 files changed, 14 insertions(+), 99 deletions(-)
