d81a07b7e5
If you have x == 1 || x == 2 || x == 3 || x == 4, the pass considered the set
{x==1, x==2, x==3, x==4}
and then also
{x==2, x==3, x==4}
{x==3, x==4}
Since the comparison is itself linear in the size of the set, this was overall
taking time quadratic in the length of the || or && sequence.
Worse, if it found duplicates, they'd be reported a quadratic number of times.
This CL cuts the time and output to linear by avoiding already-checked
subexpressions. This cuts the time spent analyzing cmd/compile/internal/ssa
(with all passes enabled, not just this one) by 20%.
Fixes golang/go#28086.
Change-Id: I812f64bd5a44fea995c9ab0c4fa2fbefb44037ce
Reviewed-on: https://go-review.googlesource.com/c/tools/+/176457
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Alan Donovan <adonovan@google.com>
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|---|---|---|
| .. | ||
| asmdecl | ||
| assign | ||
| atomic | ||
| atomicalign | ||
| bools | ||
| buildssa | ||
| buildtag | ||
| cgocall | ||
| composite | ||
| copylock | ||
| ctrlflow | ||
| deepequalerrors | ||
| errorsas | ||
| findcall | ||
| httpresponse | ||
| inspect | ||
| internal/analysisutil | ||
| loopclosure | ||
| lostcancel | ||
| nilfunc | ||
| nilness | ||
| pkgfact | ||
| printf | ||
| shadow | ||
| shift | ||
| stdmethods | ||
| structtag | ||
| tests | ||
| unmarshal | ||
| unreachable | ||
| unsafeptr | ||
| unusedresult | ||
| README | ||
README
This directory does not contain a Go package, but acts as a container for various analyses that implement the golang.org/x/tools/go/analysis API and may be imported into an analysis tool. By convention, each package foo provides the analysis, and each command foo/cmd/foo provides a standalone driver.