| commit | 43e6923131c4c83e02f5263a9632d81819f15a62 | [log] [tgz] |
|---|---|---|
| author | Josh Bleecher Snyder <josharian@gmail.com> | Mon Dec 22 11:33:47 2014 -0800 |
| committer | Josh Bleecher Snyder <josharian@gmail.com> | Wed Jan 07 22:36:06 2015 +0000 |
| tree | 0300e13f1f583aaac87fef92c999c9e50d1908f5 | |
| parent | 43c87aa481f4e10777b05bf05edd15403853348f [diff] |
cmd/gc: optimize existence-only map lookups
The compiler converts 'val, ok = m[key]' to
tmp, ok = <runtime call>
val = *tmp
For lookups of the form '_, ok = m[key]',
the second statement is unnecessary.
By not generating it we save a nil check.
Change-Id: I21346cc195cb3c62e041af8b18770c0940358695
Reviewed-on: https://go-review.googlesource.com/1975
Reviewed-by: Russ Cox <rsc@golang.org>
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