commit 2ea7d3461bb41d0ae12b56ee52d43314bcdb97f9 [browse]
Author: Russ Cox
Date: 2017-10-25 14:29:22 -04:00

[release-branch.go1.9] go1.9.2

Change-Id: Idb72e9f562887680e0b287649a4ae1325d7e3eb5
Reviewed-on: https://go-review.googlesource.com/71271
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Chris Broadfoot <cbro@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

commit d93cb46280ae4710c5c6113159c7973a08a72249 [browse]
Author: Russ Cox
Date: 2017-10-14 22:47:24 -04:00

[release-branch.go1.9] runtime: use simple, more robust fastrandn

CL 36932 (speed up fastrandn) made it faster but introduced
bad interference with some properties of fastrand itself, making
fastrandn not very random in certain ways. In particular, certain
selects are demonstrably unfair.

For Go 1.10 the new faster fastrandn has induced a new fastrand,
which in turn has caused other follow-on bugs that are still being
discovered and fixed.

For Go 1.9.2, just go back to the barely slower % implementation
that we used in Go 1.8 and earlier. This should restore fairness in
select and any other problems caused by the clever fastrandn.

The test in this CL is copied from CL 62530.

Fixes #22253.

Change-Id: Ibcf948a7bce981452e05c90dbdac122043f6f813
Reviewed-on: https://go-review.googlesource.com/70991
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>

commit 78952c06c53c8455d03430b17b5a7fe2693b5d35 [browse]
Author: Keith Randall
Date: 2017-09-21 12:52:38 -07:00

[release-branch.go1.9] cmd/compile: fix sign-extension merging rules

If we have

  y = <int16> (MOVBQSX x)
  z = <int32> (MOVWQSX y)

We used to use this rewrite rule:

(MOVWQSX x:(MOVBQSX _)) -> x

But that resulted in replacing z with a value whose type
is only int16.  Then if z is spilled and restored, it gets
zero extended instead of sign extended.

Instead use the rule

(MOVWQSX (MOVBQSX x)) -> (MOVBQSX x)

The result is has the correct type, so it can be spilled
and restored correctly.  It might mean that a few more extension
ops might not be eliminated, but that's the price for correctness.

Fixes #21963

Change-Id: I6ec82c3d2dbe43cc1fee6fb2bd6b3a72fca3af00
Reviewed-on: https://go-review.googlesource.com/65290
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-on: https://go-review.googlesource.com/70986
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>

commit 79996e4a1d33b7404ee076d7455ff8dcc7270250 [browse]
Author: Keith Randall
Date: 2017-08-28 12:57:52 -07:00

[release-branch.go1.9] cmd/compile: avoid generating large offsets

The assembler barfs on large offsets. Make sure that all the
instructions that need to have their offsets in an int32
  1) check on any rule that computes offsets for such instructions
  2) change their aux fields so the check builder checks it.

The assembler also silently misassembled offsets between 1<<31
and 1<<32. Add a check in the assembler to barf on those as well.

Fixes #21655

Change-Id: Iebf24bf10f9f37b3ea819ceb7d588251c0f46d7d
Reviewed-on: https://go-review.googlesource.com/59630
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
Reviewed-on: https://go-review.googlesource.com/70981
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>

commit f36b12657c71753029aeefa5e0af3c1607ffe9bb [browse]
Author: Michael Matloob
Date: 2017-09-12 12:22:22 -04:00

[release-branch.go1.9] runtime: in cpuProfile.addExtra, set p.lostExtra to 0 after flush

After the number of lost extra events are written to the the cpuprof log,
the number of lost extra events should be set to zero, or else, the next
time time addExtra is logged, lostExtra will be overcounted. This change
resets lostExtra after its value is written to the log.

Fixes #21836

Change-Id: I8a6ac9c61e579e7a5ca7bdb0f3463f8ae8b9f864
Reviewed-on: https://go-review.googlesource.com/63270
Reviewed-by: Austin Clements <austin@google.com>
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-on: https://go-review.googlesource.com/70974
Run-TryBot: Russ Cox <rsc@golang.org>