Adds an assembly implementation of sha256.block for ppc64le to improve its
performance.  This implementation is largely based on the original amd64
implementation, which unrolls the 64 iterations of the inner loop.

Fixes #17652

benchmark               old ns/op     new ns/op     delta
BenchmarkHash8Bytes     1263          767           -39.27%
BenchmarkHash1K         14048         7766          -44.72%
BenchmarkHash8K         102245        55626         -45.60%

benchmark               old MB/s     new MB/s     speedup
BenchmarkHash8Bytes     6.33         10.43        1.65x
BenchmarkHash1K         72.89        131.85       1.81x
BenchmarkHash8K         80.12        147.27       1.84x

Change-Id: Ib4adf429423b20495580400be10bd7e171bcc70b
Reviewed-on: https://go-review.googlesource.com/32318Reviewed-by: Carlos Eduardo Seo <cseo@linux.vnet.ibm.com>
Reviewed-by: David Chase <drchase@google.com>
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Adds an assembly implementation of sha512.block for ppc64le to improve its
performance.  This implementation is largely based on the original amd64
implementation, unrolling the 80 iterations of the inner loop.

Fixes #17660

benchmark               old ns/op     new ns/op     delta
BenchmarkHash8Bytes     1715          1133          -33.94%
BenchmarkHash1K         10098         5513          -45.41%
BenchmarkHash8K         68004         35278         -48.12%

benchmark               old MB/s     new MB/s     speedup
BenchmarkHash8Bytes     4.66         7.06         1.52x
BenchmarkHash1K         101.40       185.72       1.83x
BenchmarkHash8K         120.46       232.21       1.93x

Change-Id: Ifd55a49a24cb159b3a09a8e928c3f37727aca103
Reviewed-on: https://go-review.googlesource.com/32320Reviewed-by: Carlos Eduardo Seo <cseo@linux.vnet.ibm.com>
Reviewed-by: David Chase <drchase@google.com>
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

These were accidentally removed by a rollback cl: golang.org/cl/32441

Change-Id: I0cfa8b3397be324dabfb8f33b6548a03c10571eb
Reviewed-on: https://go-review.googlesource.com/32334Reviewed-by: Alan Donovan <adonovan@google.com>

This reverts commit b33030a7.

Reason for revert: We're going to try to get the code in this change
submitted in smaller, more carefully reviewed changes.

Change-Id: I4175f4b297f0e69fb78b11f9dc0bd82f27865be7
Reviewed-on: https://go-review.googlesource.com/32441Reviewed-by: Russ Cox <rsc@golang.org>

Fixes #16997

Change-Id: I9ca27d8cff1905584862997d0e8a11ce3c4c21cb
Reviewed-on: https://go-review.googlesource.com/30750Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Also add a link to more information about isolation levels as defined by the
SQL standard. Fixes #17682.

Change-Id: I94c53b713f4c882af40cf15fe5f1e5dbc53ea741
Reviewed-on: https://go-review.googlesource.com/32418Reviewed-by: Daniel Theophanes <kardianos@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Change-Id: If6eb3a7c9ad48a517e584567b1003479c1df6cca
Reviewed-on: https://go-review.googlesource.com/32136Reviewed-by: Daniel Theophanes <kardianos@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Fixes #17686.

Change-Id: I7d07c367e50b448579f9855bea43df76ddb82bd0
Reviewed-on: https://go-review.googlesource.com/32420Reviewed-by: Rob Pike <r@golang.org>

Does not handle imports of packages with exported aliases yet.

For #17592.

Change-Id: Iee63fb9d521014995003a417271fbe0384ae04ef
Reviewed-on: https://go-review.googlesource.com/32108Reviewed-by: Alan Donovan <adonovan@google.com>

The map[typeOff]*_type object is created at run time and stored in
the moduledata. The moduledata object is marked by the linker as
SNOPTRDATA, so the reference is ignored by the GC. Running
misc/cgo/testplugin/test.bash with GOGC=1 will eventually collect
the typemap and crash.

This bug probably comes up in -linkshared binaries in Go 1.7.
I don't know why we haven't seen a report about this yet.

Fixes #17680

Change-Id: I0e9b5c006010e8edd51d9471651620ba665248d3
Reviewed-on: https://go-review.googlesource.com/32430
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Michael Hudson-Doyle <michael.hudson@canonical.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Plumb the import path of a plugin package through to the linker, and
use it as the prefix on the exported symbol names.

Before this we used the basename of the plugin file as the prefix,
which could conflict and result in multiple loaded plugins sharing
symbols that are distinct.

Fixes #17155
Fixes #17579

Change-Id: I7ce966ca82d04e8507c0bcb8ea4ad946809b1ef5
Reviewed-on: https://go-review.googlesource.com/32355Reviewed-by: Ian Lance Taylor <iant@golang.org>

Previously, we were off by one.

Also fix a comment typo.

Change-Id: Ib94d23acc56d5fccd44144f71655481f98803ac8
Reviewed-on: https://go-review.googlesource.com/32149Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>
Run-TryBot: Joe Tsai <thebrokentoaster@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

This is convenient for direct use of `go tool cgo`. We can also use it
from the go tool to reduce the length of the file names that cgo
generates.

Update #17070.

Change-Id: I8466a0a2cc68a732d17d07319e303497715bac8c
Reviewed-on: https://go-review.googlesource.com/32354
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>

Disabled by https://golang.org/cl/53020044 due to false positives.
Reenable and model properly.

Fixes #17306.

Change-Id: I28405ddfcd17f58cf1427c300273212729154359
Reviewed-on: https://go-review.googlesource.com/31589
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>

This field is a zero length array and has little use. Since Go 1.5, trailing
zero-length arrays take up space. Both syscall.UnixRights() and
syscall.ParseSocketControlMessage() depend on being able to do an unsafe cast
of socket control message data to Cmsghdr this is only safe if the socket
control message data is greater than or equal to the size of Cmsghdr. Since
control message data that is equal in size to Cmsghdr without X__cmsg_data is
a valid socket control message, we must remove X__cmsg_data or not perform the
unsafe cast.

Removing X__cmsg_data will prevent Go code that uses X__cmsg_data from
compiling, but removing the unsafe cast will cause Go code that uses
X__cmsg_data to fail or exhibit undefined behavior at runtime. It was
therefore decided that removing X__cmsg_data was the better option.

Fixes #17649

Change-Id: I39f323f978eca09d62da5785c5c5c9c7cbdf8c31
Reviewed-on: https://go-review.googlesource.com/32319Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Prior to this change, it was implied that transaction properties
would be carried in the context value. However, no such properties
were defined, not even common ones. Define two common properties:
isolation level and read-only. Drivers may choose to support
additional transaction properties. It is not expected any
further transaction properties will be added in the future.

Change-Id: I2f680115a14a1333c65ba6f943d9a1149d412918
Reviewed-on: https://go-review.googlesource.com/31258
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

This updates the runtime to HEAD to keep it aligned and fixes some bugs.

http://llvm.org/viewvc/llvm-project?view=revision&revision=285454
fixes the crash on darwin related to unaligned data section (#17065).

http://llvm.org/viewvc/llvm-project?view=revision&revision=285451
enables core dumps by default (#16527).

http://llvm.org/viewvc/llvm-project?view=revision&revision=285455
adds a hook to obtain number of races reported so far (#15972).
Can now be obtained with:

//go:nosplit
func RaceReportCount() int {
	var n uint64
	racecall(&__tsan_report_count, uintptr(unsafe.Pointer(&n)), 0, 0, 0)
	return int(n)
}

Fixes #16527.
Fixes #17065.
Update #15972.

Change-Id: I8f869cb6275c9521a47303f3810a9965e9314357
Reviewed-on: https://go-review.googlesource.com/32160
Run-TryBot: Dmitry Vyukov <dvyukov@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

No point in computing this info on startup.
Compute it at build time.
This lets us spend more time computing & checking the size classes.

Improve the div magic for rounding to the start of an object.
We can now use 32-bit multiplies & shifts, which should help
32-bit platforms.

The static data is <1KB.

The actual size classes are not changed by this CL.

Change-Id: I6450cec7d1b2b4ad31fd3f945f504ed2ec6570e7
Reviewed-on: https://go-review.googlesource.com/32219
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>

This fixes systems for which ccache is the default compiler.

Also remove a couple of temporary files created by TestImportMain.

Fixes #17668.

Change-Id: I1edefdcec5f417be0533c146253c35ff4928c1c0
Reviewed-on: https://go-review.googlesource.com/32328Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Provides redirection support for 307, 308 server statuses.
Provides redirection support for DELETE method.

Updates old tests that assumed all redirects were treated
the way 301, 302 and 303 are processed.

Fixes #9348
Fixes #10767
Fixes #13994

Change-Id: Iffa8dbe0ff28a1afa8da59869290ec805b1dd2c4
Reviewed-on: https://go-review.googlesource.com/29852
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Change-Id: Iec469846dc8b5a747ad81690000f1f6f53721ea1
Reviewed-on: https://go-review.googlesource.com/32372Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

The GZIP format records the ModTime as an uint32 counting seconds since
the Unix epoch. The zero value is explicitly defined in section 2.3.1
as meaning no timestamp is available.

Currently, the Writer always encodes the ModTime even if it is the zero
time.Time value, which causes the Writer to try and encode the value
-62135596800 into the uint32 MTIME field. This causes an overflow and
results in our GZIP files having MTIME fields indicating a date in 2042-07-13.

We alter the Writer to only encode ModTime if the value does not underflow
the MTIME field (i.e., it is newer than the Unix epoch). We do not attempt
to fix what happens when the timestamp overflows in the year 2106.

We alter the Reader to only decode ModTime if the value is non-zero.
There is no risk of overflowing time.Time when decoding.

Fixes #17663

Change-Id: Ie1b65770c6342cd7b14aeebe10e5a49e6c9eb730
Reviewed-on: https://go-review.googlesource.com/32325Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Updates http2 to x/net git rev 76c1a11e for:

     http2: initialize Server.IdleTimeout from http.Server as http1 does
     https://golang.org/cl/32230

     http2: change how Server.IdleTimeout is initialized from http.Server
     https://golang.org/cl/32323

Fixes #14204

Change-Id: I099f89fcd0d8bc0e42da163ae0a3b786fd81292f
Reviewed-on: https://go-review.googlesource.com/32322
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Because git.

Change-Id: Ia1e7c6ba0e8c4d47f993487d2483cbb213b465e5
Reviewed-on: https://go-review.googlesource.com/32351
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

After the final slash, dots are %-escaped when constructing a symbol name,
so that in the actual symbol table, the import path githost.com/my.git
becomes githost.com/my%2egit. In this case, -X githost.com/my.git.Value=foo
needs to set githost.com/my%2egit.Value. This is a detail of the object format
and not something users should know or depend on, so apply the escaping
as needed.

People who have run across this already and figured out and started using
the escaped forms with -X will find those forms not working anymore.
That is, -X githost.com/my%2egit.Value=foo is the Go 1.7 workaround but
will stop working in Go 1.8 once this proper fix is in place.
People who need to keep scripts working with older and newer versions of Go
can safely pass both forms, and one will be ignored:

    -X githost.com/my%2egit.Value=foo -X githost.com/my.git.Value=foo

Fixes #16710.

Change-Id: I0e994ccdd412a4eb8349fefce9aeb3bfc9a83cd8
Reviewed-on: https://go-review.googlesource.com/31970
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Also fix behavior of Buffers.WriteTo when writev returns an error.

Fixes #16266.

Change-Id: Idc9503408ce2cb460663768fab86035cbab11aef
Reviewed-on: https://go-review.googlesource.com/31584
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Writes gzip-format uncompressed files.

Change-Id: Id5dc01852e21732978700fd9efcc2d4a5899ffeb
Reviewed-on: https://go-review.googlesource.com/32260
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>
Reviewed-by: Michael Matloob <matloob@golang.org>

The filepath.Abs function in windows did not call Clean as the
documentation claimed.  This change not only fixes that behavior but
also adjusts TestAbs to verify Abs calls Clean as documented.

Fixes #17210

Change-Id: I20c5f5026042fd7bd9d929ff5b17c8b2653f8afe
Reviewed-on: https://go-review.googlesource.com/32292Reviewed-by: Alex Brainman <alex.brainman@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Alex Brainman <alex.brainman@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Change-Id: I017c2ef7cc6248d3f4e38a791cd2576e941984ed
Reviewed-on: https://go-review.googlesource.com/32156
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Improves the error message by moving the field name before the body
of a struct, in the error message for unknown fields for structs.

* Exhibit:
Given program:

package main

import "time"

func main() {
  _ = struct {
    about      string
    before     map[string]uint
    update     map[string]int
    updateTime time.Time
    expect     map[string]int
  }{
    about:   "this one",
    updates: map[string]int{"gopher": 10},
  }
}

* Before:
./issue17631.go:20: unknown struct { about string; before map[string]uint;
 update map[string]int; updateTime time.Time; expect map[string]int } field
'updates' in struct literal

* After:
./issue17631.go:20: unknown field 'updates' in struct literal of type { about string;
before map[string]uint; update map[string]int; updateTime time.Time;
expect map[string]int }

Fixes #17631

Change-Id: I76842616411b931b5ad7a76bd42860dfde7739f4
Reviewed-on: https://go-review.googlesource.com/32240Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>

I did 'export GORACE=atexit_sleep_ms=0' in a console
and then was puzzled as to why race tests fail.
Existing GORACE env var may (or may not) override
the one that we setup.
Filter out GORACE as we do for other important env vars.

Change-Id: I29be86b0cbb9b5dc7f9efb15729ade86fc79b0e0
Reviewed-on: https://go-review.googlesource.com/32163Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Change-Id: Iec35f9b62982da40de400397bc456149216303dc
Reviewed-on: https://go-review.googlesource.com/32297Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Change-Id: Icea4661db4a254e64b2129f429e5ef21ec1612cb
Reviewed-on: https://go-review.googlesource.com/32162
Run-TryBot: Martin Möhrmann <martisch@uos.de>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>

The docs used to imply that using == would compare Locations, but of
course it just compares Location pointers, which will have unpredictable
results depending on how the pointers are loaded.

Change-Id: I783c1309e476a9616a1c1c290eac713aba3b0b57
Reviewed-on: https://go-review.googlesource.com/32332Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Updates #15228.

Change-Id: Iefdffa146703ee1c04afc2b71d9de1f0a0811f86
Reviewed-on: https://go-review.googlesource.com/32146
Run-TryBot: Mikio Hara <mikioh.mikioh@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Fixes #17623.

Change-Id: I4717e8399f955c9be7ba19108bb0bcc108187c04
Reviewed-on: https://go-review.googlesource.com/32147
Run-TryBot: Mikio Hara <mikioh.mikioh@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

On solaris/amd64 sometimes the reported cycle count is negative. Replace
with 0.

Change-Id: I364eea5ca072281245c7ab3afb0bf69adc3a8eae
Reviewed-on: https://go-review.googlesource.com/32258Reviewed-by: Ian Lance Taylor <iant@golang.org>

Use "have" and "want" and multiple lines like other similar error
messages. Also, fix handling of ... and multi-value function calls.

Fixes #17650.

Change-Id: I4850e79c080eac8df3b92a4accf9e470dff63c9a
Reviewed-on: https://go-review.googlesource.com/32261Reviewed-by: Robert Griesemer <gri@golang.org>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

On amd64p32, rt0_go attempts to reserve 128 bytes of scratch space on
the stack, but due to a register mixup this ends up being a no-op. Fix
this so we actually reserve the stack space.

Change-Id: I04dbfbeb44f3109528c8ec74e1136bc00d7e1faa
Reviewed-on: https://go-review.googlesource.com/32331
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

With the hybrid barrier in place, we can now disable stack rescanning
by default. This commit adds a "gcrescanstacks" GODEBUG variable that
is off by default but can be set to re-enable STW stack rescanning.
The plan is to leave this off but available in Go 1.8 for debugging
and as a fallback.

With this change, worst-case mark termination time at GOMAXPROCS=12
*not* including time spent stopping the world (which is still
unbounded) is reliably under 100 µs, with a 95%ile around 50 µs in
every benchmark I tried (the go1 benchmarks, the x/benchmarks garbage
benchmark, and the gcbench activegs and rpc benchmarks). Including
time spent stopping the world usually adds about 20 µs to total STW
time at GOMAXPROCS=12, but I've seen it add around 150 µs in these
benchmarks when a goroutine takes time to reach a safe point (see
issue #10958) or when stopping the world races with goroutine
switches. At GOMAXPROCS=1, where this isn't an issue, worst case STW
is typically 30 µs.

The go-gcbench activegs benchmark is designed to stress large numbers
of dirty stacks. This commit reduces 95%ile STW time for 500k dirty
stacks by nearly three orders of magnitude, from 150ms to 195µs.

This has little effect on the throughput of the go1 benchmarks or the
x/benchmarks benchmarks.

name         old time/op  new time/op  delta
XGarbage-12  2.31ms ± 0%  2.32ms ± 1%  +0.28%  (p=0.001 n=17+16)
XJSON-12     12.4ms ± 0%  12.4ms ± 0%  +0.41%  (p=0.000 n=18+18)
XHTTP-12     11.8µs ± 0%  11.8µs ± 1%    ~     (p=0.492 n=20+18)

It reduces the tail latency of the x/benchmarks HTTP benchmark:

name      old p50-time  new p50-time  delta
XHTTP-12    489µs ± 0%    491µs ± 1%  +0.54%  (p=0.000 n=20+18)

name      old p95-time  new p95-time  delta
XHTTP-12    957µs ± 1%    960µs ± 1%  +0.28%  (p=0.002 n=20+17)

name      old p99-time  new p99-time  delta
XHTTP-12   1.76ms ± 1%   1.64ms ± 1%  -7.20%  (p=0.000 n=20+18)

Comparing to the beginning of the hybrid barrier implementation
("runtime: parallelize STW mcache flushing") shows that the hybrid
barrier trades a small performance impact for much better STW latency,
as expected. The magnitude of the performance impact is generally
small:

name                      old time/op    new time/op    delta
BinaryTree17-12              2.37s ± 1%     2.42s ± 1%  +2.04%  (p=0.000 n=19+18)
Fannkuch11-12                2.84s ± 0%     2.72s ± 0%  -4.00%  (p=0.000 n=19+19)
FmtFprintfEmpty-12          44.2ns ± 1%    45.2ns ± 1%  +2.20%  (p=0.000 n=17+19)
FmtFprintfString-12          130ns ± 1%     134ns ± 0%  +2.94%  (p=0.000 n=18+16)
FmtFprintfInt-12             114ns ± 1%     117ns ± 0%  +3.01%  (p=0.000 n=19+15)
FmtFprintfIntInt-12          176ns ± 1%     182ns ± 0%  +3.17%  (p=0.000 n=20+15)
FmtFprintfPrefixedInt-12     186ns ± 1%     187ns ± 1%  +1.04%  (p=0.000 n=20+19)
FmtFprintfFloat-12           251ns ± 1%     250ns ± 1%  -0.74%  (p=0.000 n=17+18)
FmtManyArgs-12               746ns ± 1%     761ns ± 0%  +2.08%  (p=0.000 n=19+20)
GobDecode-12                6.57ms ± 1%    6.65ms ± 1%  +1.11%  (p=0.000 n=19+20)
GobEncode-12                5.59ms ± 1%    5.65ms ± 0%  +1.08%  (p=0.000 n=17+17)
Gzip-12                      223ms ± 1%     223ms ± 1%  -0.31%  (p=0.006 n=20+20)
Gunzip-12                   38.0ms ± 0%    37.9ms ± 1%  -0.25%  (p=0.009 n=19+20)
HTTPClientServer-12         77.5µs ± 1%    78.9µs ± 2%  +1.89%  (p=0.000 n=20+20)
JSONEncode-12               14.7ms ± 1%    14.9ms ± 0%  +0.75%  (p=0.000 n=20+20)
JSONDecode-12               53.0ms ± 1%    55.9ms ± 1%  +5.54%  (p=0.000 n=19+19)
Mandelbrot200-12            3.81ms ± 0%    3.81ms ± 1%  +0.20%  (p=0.023 n=17+19)
GoParse-12                  3.17ms ± 1%    3.18ms ± 1%    ~     (p=0.057 n=20+19)
RegexpMatchEasy0_32-12      71.7ns ± 1%    70.4ns ± 1%  -1.77%  (p=0.000 n=19+20)
RegexpMatchEasy0_1K-12       946ns ± 0%     946ns ± 0%    ~     (p=0.405 n=18+18)
RegexpMatchEasy1_32-12      67.2ns ± 2%    67.3ns ± 2%    ~     (p=0.732 n=20+20)
RegexpMatchEasy1_1K-12       374ns ± 1%     378ns ± 1%  +1.14%  (p=0.000 n=18+19)
RegexpMatchMedium_32-12      107ns ± 1%     107ns ± 1%    ~     (p=0.259 n=18+20)
RegexpMatchMedium_1K-12     34.2µs ± 1%    34.5µs ± 1%  +1.03%  (p=0.000 n=18+18)
RegexpMatchHard_32-12       1.77µs ± 1%    1.79µs ± 1%  +0.73%  (p=0.000 n=19+18)
RegexpMatchHard_1K-12       53.6µs ± 1%    54.2µs ± 1%  +1.10%  (p=0.000 n=19+19)
Template-12                 61.5ms ± 1%    63.9ms ± 0%  +3.96%  (p=0.000 n=18+18)
TimeParse-12                 303ns ± 1%     300ns ± 1%  -1.08%  (p=0.000 n=19+20)
TimeFormat-12                318ns ± 1%     320ns ± 0%  +0.79%  (p=0.000 n=19+19)
Revcomp-12 (*)               509ms ± 3%     504ms ± 0%    ~     (p=0.967 n=7+12)
[Geo mean]                  54.3µs         54.8µs       +0.88%

(*) Revcomp is highly non-linear, so I only took samples with 2
iterations.

name         old time/op  new time/op  delta
XGarbage-12  2.25ms ± 0%  2.32ms ± 1%  +2.74%  (p=0.000 n=16+16)
XJSON-12     11.6ms ± 0%  12.4ms ± 0%  +6.81%  (p=0.000 n=18+18)
XHTTP-12     11.6µs ± 1%  11.8µs ± 1%  +1.62%  (p=0.000 n=17+18)

Updates #17503.

Updates #17099, since you can't have a rescan list bug if there's no
rescan list. I'm not marking it as fixed, since gcrescanstacks can
still be set to re-enable the rescan lists.

Change-Id: I6e926b4c2dbd4cd56721869d4f817bdbb330b851
Reviewed-on: https://go-review.googlesource.com/31766Reviewed-by: Rick Hudson <rlh@golang.org>