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3 Commits

Author SHA1 Message Date
Alan Donovan
b7f0150d16 container/intsets: popcount: use POPCNT on amd64, Hacker's Delight algorithm on 386
This function accounts for 2% of "godoc -analysis=pointer"
and this change makes it twice as fast---and simpler.

Added test and benchmark.

Change-Id: I8578fa42dce34df057d81f6c522a7b4e0506d09d
Reviewed-on: https://go-review.googlesource.com/15211
Run-TryBot: Robert Griesemer <gri@golang.org>
Reviewed-by: Ilya Tocar <ilya.tocar@intel.com>
Reviewed-by: Robert Griesemer <gri@golang.org>
2015-10-01 19:57:28 +00:00
Alan Donovan
e1b97610f0 go.tools/container/intsets: fix compile error on 32-bit platforms.
Also, fix typo.

LGTM=gri
R=gri
CC=golang-codereviews
https://golang.org/cl/99310043
2014-05-15 14:03:05 -04:00
Alan Donovan
61c5c64029 go.tools/container/intsets: Sparse: a space-efficient representation for ordered sets of int values.
intsets.Sparse is a sparse bit vector.  It uses space proportional
to the number of elements, not the maximum element (as is the case		for a dense bit vector).

A forthcoming CL will make use of it in go/pointer, where it reduces
solve time by 78%.  A similar representation is used for Andersen's
analysis in gcc and LLVM.

+ Tests.

LGTM=sameer, crawshaw, gri
R=gri
CC=crawshaw, golang-codereviews, sameer
https://golang.org/cl/10837043
2014-05-14 17:54:14 -04:00