Rematerializable ops can be inserted after the flagalloc phase,
they must therefore not clobber flags. This CL adds a check to
ensure this doesn't happen and fixes the instances where it
does currently.

amd64: ADDQconst and ADDLconst were recently changed to be
rematerializable in CL 54393 (only in tip, not 1.9). That change
has been reverted.

s390x: MOVDaddr could clobber flags when using dynamic linking due
to a ADD with immediate instruction. Change the code generation to
use LA/LAY instead.

Fixes #21080.

Change-Id: Ia85c882afa2a820a309e93775354b3169ec6d034
Reviewed-on: https://go-review.googlesource.com/63030
Run-TryBot: Michael Munday <mike.munday@ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Ilya Tocar <ilya.tocar@intel.com>

These were previously only relevant for recording scoping level so
that invalid 'fallthrough' statements could be rejected. However,
that's handled differently since CL 61130 (in particular, there's no
use of types.Block anymore), so these calls can be safely removed.

Passes toolstash-check.

Change-Id: I8631b156594df85b8d39f57acad3ebcf099d52f9
Reviewed-on: https://go-review.googlesource.com/64810
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>

Copied from CL 60630

Current results:
name          time/op
CopyNSmall-4  2.20µs ±90%
CopyNLarge-4   136µs ±56%

name          alloc/op
CopyNSmall-4  1.84kB ±21%
CopyNLarge-4   128kB ±10%

name          allocs/op
CopyNSmall-4    1.00 ± 0%
CopyNLarge-4    1.00 ± 0%

Change-Id: If08c0132a773e936c9f61bff96e0aabf58006d31
Reviewed-on: https://go-review.googlesource.com/64932
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Benchmarks:
name          old time/op    new time/op    delta
CopyNSmall-4    5.09µs ± 1%    2.25µs ±86%  -55.91%  (p=0.000 n=11+14)
CopyNLarge-4     114µs ±73%     121µs ±72%     ~     (p=0.701 n=14+14)

name          old alloc/op   new alloc/op   delta
CopyNSmall-4    34.6kB ± 0%     1.9kB ±19%  -94.60%  (p=0.000 n=12+14)
CopyNLarge-4     129kB ± 8%     127kB ±18%   -2.00%  (p=0.007 n=14+14)

name          old allocs/op  new allocs/op  delta
CopyNSmall-4      2.00 ± 0%      1.00 ± 0%  -50.00%  (p=0.000 n=14+14)
CopyNLarge-4      2.00 ± 0%      1.00 ± 0%  -50.00%  (p=0.000 n=14+14)

Benchmark code:
type Buffer struct {
	bytes.Buffer
	io.ReaderFrom
}

func BenchmarkCopyNSmall(b *testing.B) {
	bs := bytes.Repeat([]byte{0}, 1024)
	rd := bytes.NewReader(bs)
	buf := new(Buffer)
	b.ResetTimer()

	for i := 0; i < b.N; i++ {
		io.CopyN(buf, rd, 512)
		rd.Reset(bs)
	}
}

func BenchmarkCopyNLarge(b *testing.B) {
	bs := bytes.Repeat([]byte{0}, 64*1024)
	rd := bytes.NewReader(bs)
	buf := new(Buffer)
	b.ResetTimer()

	for i := 0; i < b.N; i++ {
		io.CopyN(buf, rd, (32*1024)+1)
		rd.Reset(bs)
	}
}

Change-Id: Id8d29e55758452c870cf372db640f07baec05849
Reviewed-on: https://go-review.googlesource.com/60630
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

This CL improves the readability of the tests in the bytes package by
naming the `data` test variable `testString`, using the same convention
as its counterpart, `testBytes`.

It additionally removes some type casting which was unnecessary.

Change-Id: If38b5606ce8bda0306bae24498f21cb8dbbb6377
Reviewed-on: https://go-review.googlesource.com/64931
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

This belongs to a series of clean-up changes (see below) for cmd/dist.
This is change (9).

These changes include:
(1)  apply minor fixes
(2)  restore behavior of branchtag
(3)  unleash bootstrap optimization for windows
(4)  use standard generated code header
(5)  remove trivial variables + functions
(6)  move functions for the better
(7)  simplify code segments
(8)  use bytes.Buffer for code generation
(9)  rename variables + functions

Change-Id: I9247433d7d07a2c99d15b0a4d23164bcbc042768
Reviewed-on: https://go-review.googlesource.com/61015
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Change-Id: Ib731874b9a37ff141e4305d8ccfdf7c165155da6
Reviewed-on: https://go-review.googlesource.com/64930Reviewed-by: Ian Lance Taylor <iant@golang.org>

Ceil, Floor and Trunc are pre-existing intrinsics. Round is a new
function and has been added as an intrinsic in this CL. All of the
functions can be implemented as a single 'LOAD FP INTEGER'
instruction, FIDBR, on s390x.

name   old time/op  new time/op  delta
Ceil   2.34ns ± 0%  0.85ns ± 0%  -63.74%  (p=0.000 n=5+4)
Floor  2.33ns ± 0%  0.85ns ± 1%  -63.35%  (p=0.008 n=5+5)
Round  4.23ns ± 0%  0.85ns ± 0%  -79.89%  (p=0.000 n=5+4)
Trunc  2.35ns ± 0%  0.85ns ± 0%  -63.83%  (p=0.029 n=4+4)

Change-Id: Idee7ba24a2899d12bf9afee4eedd6b4aaad3c510
Reviewed-on: https://go-review.googlesource.com/63890
Run-TryBot: Michael Munday <mike.munday@ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>

This allows io.WriteString to make use of WriteString method
implemented by pp when writing a string to fmt.State.

Fixes #20786

Change-Id: Ice7a92bf303127ad87f05562217fa076f5c589ad
Reviewed-on: https://go-review.googlesource.com/61430Reviewed-by: Rob Pike <r@golang.org>

In general, there are no guarantee that `go` command exist on $PATH.
This CL tries to get `go` command from $GOROOT/bin instead.

There are three kinds of code we should handle:
    For normal code, the CL implements goCmd() or goCmdName().
    For unit tests, the CL uses testenv.GoTool() or testenv.GoToolPath().
    For integration tests, the CL sets PATH=$GOROOT/bin:$PATH in cmd/dist.

Note that make.bash sets PATH=$GOROOT/bin:$PATH in the build process.
So this change is only useful when we use toolchain manually.

Updates #21875

Change-Id: I963b9f22ea732dd735363ececde4cf94a5db5ca2
Reviewed-on: https://go-review.googlesource.com/64650
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

This belongs to a series of clean-up changes (see below) for cmd/dist.
This is change (8).

These changes include:
(1)  apply minor fixes
(2)  restore behavior of branchtag
(3)  unleash bootstrap optimization for windows
(4)  use standard generated code header
(5)  remove trivial variables + functions
(6)  move functions for the better
(7)  simplify code segments
(8)  use bytes.Buffer for code generation
(9)  rename variables + functions
(10) remove doc.go

Change-Id: I2d5a071eb8e14690325612271432fdc5f43b108b
Reviewed-on: https://go-review.googlesource.com/61014
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Also, rename some test cases, check (*os.File).Close

For #21706

Change-Id: Ie60c4d345b2259736c823dc6001c08affcdd86e7
Reviewed-on: https://go-review.googlesource.com/64510Reviewed-by: David Crawshaw <crawshaw@golang.org>
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Check all associated templates in the set for an existing reference
to the given Tree in AddParseTree before assigning that reference
to a new or existing template. This prevents multiple html/template
Templates from referencing and modifying the same underlying Tree.

While there, fix a few existing unit tests so that they terminate
upon encountering unrecoverable failures.

Fixes #21844

Change-Id: I6b4f6996cf5467113ef94f7b91a6933dbbc21839
Reviewed-on: https://go-review.googlesource.com/64770
Run-TryBot: Rob Pike <r@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rob Pike <r@golang.org>

This belongs to a series of clean-up changes (see below) for cmd/dist.
This is change (7).

These changes include:
(1)  apply minor fixes
(2)  restore behavior of branchtag
(3)  unleash bootstrap optimization for windows
(4)  use standard generated code header
(5)  remove trivial variables + functions
(6)  move functions for the better
(7)  simplify code segments
(8)  use bytes.Buffer for code generation
(9)  rename variables + functions
(10) remove doc.go

Change-Id: Ia3c33ef060b4baaef354b729ba82ed0b28e52857
Reviewed-on: https://go-review.googlesource.com/61013
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

The change in https://golang.org/cl/43295 added warning about spaces in
struct tags. However, in XML tags it is expected that there will be a
space between the namespace and the local name.

Change-Id: Ic31c3bdae30797f406f25c737b83bbe2de1ed1db
Reviewed-on: https://go-review.googlesource.com/62570
Run-TryBot: Rob Pike <r@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rob Pike <r@golang.org>

Change-Id: I16475e9bb055b934302870ccb5136174dc3bc817
Reviewed-on: https://go-review.googlesource.com/64670
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

We used to have {Arg,Auto,Extern}Symbol structs with which we wrapped
a *gc.Node or *obj.LSym before storing them in the Aux field
of an ssa.Value.  This let the SSA part of the compiler distinguish
between autos and args, for example.  We no longer need the wrappers
as we can query the underlying objects directly.

There was also some sloppy usage, where VarDef had a *gc.Node
directly in its Aux field, whereas the use of that variable had
that *gc.Node wrapped in an AutoSymbol. Thus the Aux fields didn't
match (using ==) when they probably should.
This sloppy usage cleanup is the only thing in the CL that changes the
generated code - we can get rid of some more unused auto variables if
the matching happens reliably.

Removing this wrapper also lets us get rid of the varsyms cache
(which was used to prevent wrapping the same *gc.Node twice).

Change-Id: I0dedf8f82f84bfee413d310342b777316bd1d478
Reviewed-on: https://go-review.googlesource.com/64452
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

If a function with nonzero frame but zero-sized return value is
Call'd, we may write a past-the-end pointer in preparing the
return Values. Fix by return the zero value for zero-sized
return value.

Fixes #21717.

Change-Id: I5351cd86d898467170a888b4c3fc9392f0e7aa3b
Reviewed-on: https://go-review.googlesource.com/60811
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>

There was unprotected access to Logger.flag in log.Output which
could lead to data race in cases when log.SetFlags called simultaneously.
For example, "hot" switching on/off debug-mode for Logger by log.SetFlags
while application still writing logs.

Fixes #21935

Change-Id: I36be25f23cad44cde62ed1af28a30d276400e1b8
Reviewed-on: https://go-review.googlesource.com/64710Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>
Run-TryBot: Joe Tsai <thebrokentoaster@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Previously, after inlining a call, we made a second pass to rewrite
the AST's position information to record the inlined stack frame. The
call arguments were part of this AST, but it would be incorrect to
rewrite them too, so extra effort was made to temporarily remove them
while the position rewriting was done.

However, this extra logic was only done for regular arguments: it was
not done for receiver arguments. Consequently if m was inlined in
"f().m(g(), h())", g and h would have correct call frames, but f would
appear to be called by m.

The fix taken by this CL is to merge setpos into inlsubst and only
rewrite position information for nodes that were actually copied from
the original function AST body. As a side benefit, this eliminates an
extra AST pass and some AST walking code.

Fixes #21879.

Change-Id: I22b25c208313fc25c358d3a2eebfc9b012400084
Reviewed-on: https://go-review.googlesource.com/64470
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>

We previously used bare strings, which made it difficult to see (and
to cross-reference) the set of allowed context values.

This change is purely cosmetic, but makes it easier for me to
understand how to address #21878.

updates #21878

Change-Id: I9027d94fd5997a0fe857c0055dea8719e1511f03
Reviewed-on: https://go-review.googlesource.com/63830
Run-TryBot: Bryan Mills <bcmills@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Change-Id: Ide7fe6b09247b7a6befbdfc2d6ce5988aa1df323
Reviewed-on: https://go-review.googlesource.com/61131Reviewed-by: Robert Griesemer <gri@golang.org>

Previously, we used OXFALL vs OFALL to distinguish fallthrough
statements that had been validated. Because in the Node AST we flatten
statement blocks, OXCASE and OXFALL needed to keep track of their
block scopes for this purpose.

Now that we have an AST that keeps these separate, we can just perform
the validation earlier.

Passes toolstash-check.

Fixes #14540.

Change-Id: I8421eaba16c2b3b72c9c5483b5cf20b14261385e
Reviewed-on: https://go-review.googlesource.com/61130
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>

Change-Id: Ief6bad2d15461d455e7230eadd9b42b27d04ec8b
Reviewed-on: https://go-review.googlesource.com/64630
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

When we introduced the distinction between "defined" and "alias" types
we retained the notion of a "named" type (any type with a name). The
predeclared types (which all have names) simply remained named types.

This CL clarifies the spec by stating excplicitly which predeclared
types are defined types (or at least "act" like defined types), and
which ones are alias types.

Fixes #21785.

Change-Id: Ia8ae133509eb5d738e6757b3442c9992355e3535
Reviewed-on: https://go-review.googlesource.com/64591Reviewed-by: Russ Cox <rsc@golang.org>

This, in turn, to make it work with x/text’s
go generate.

Also eliminates need to manually update version
string in maketables.go.

Change-Id: Id5a8b8e27bdce5b1b5920eb9223a2d27b889149a
Reviewed-on: https://go-review.googlesource.com/63952
Run-TryBot: Marcel van Lohuizen <mpvl@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Nigel Tao <nigeltao@golang.org>

Change-Id: Ifeb93f6dc75fb5f90d595211fb0f97a89bf74526
Reviewed-on: https://go-review.googlesource.com/64530Reviewed-by: Dave Cheney <dave@cheney.net>
Run-TryBot: Dave Cheney <dave@cheney.net>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Change-Id: I011486993b167e65c69da1c8390bbcc625ca58c3
Reviewed-on: https://go-review.googlesource.com/64331Reviewed-by: Rob Pike <r@golang.org>

Found by running gofmt -s on the file in question.

Change-Id: I84511bd2bc75dff196930a7a87ecf5a2aca2fbb8
Reviewed-on: https://go-review.googlesource.com/64310Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

By setting both a valid size and alignment for broken recursive types,
we can appease some more safety checks and prevent compiler crashes.

Fixes #21882.

Change-Id: Ibaa137d8aa2c2a9d521462f144d7016c4abfd6e7
Reviewed-on: https://go-review.googlesource.com/64430
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>

Expand documentation in of the internal urlFilter function
to explain why URLs with schemes other than "http", "https",
and "mailto" are filtered out.

Fixes #20586

Change-Id: I1f65ff6e15fc4cd325489327c40f8c141904bf5c
Reviewed-on: https://go-review.googlesource.com/52853Reviewed-by: Mike Samuel <mikesamuel@gmail.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

The comment was a left-over from the long-past move
of these two packages from x/tools to the std lib.

Fixes #21791.

Change-Id: I65cbebf479e609be0204b58edb6506c6403aec9b
Reviewed-on: https://go-review.googlesource.com/64250
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Alan Donovan <adonovan@google.com>

Change-Id: Ia42e3479c852a88968947411de8b32e5bcda5ae3
Reviewed-on: https://go-review.googlesource.com/64371Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>
Run-TryBot: Joe Tsai <thebrokentoaster@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

To support the efficient packing and extracting of sparse files,
add two new methods:
	func Reader.WriteTo(io.Writer) (int64, error)
	func Writer.ReadFrom(io.Reader) (int64, error)

If the current archive entry is sparse and the provided io.{Reader,Writer}
is also an io.Seeker, then use Seek to skip past the holes.
If the last region in a file entry is a hole, then we seek to 1 byte
before the EOF:
	* for Reader.WriteTo to write a single byte
	to ensure that the resulting filesize is correct.
	* for Writer.ReadFrom to read a single byte
	to verify that the input filesize is correct.

The downside of this approach is when the last region in the sparse file
is a hole. In the case of Reader.WriteTo, the 1-byte write will cause
the last fragment to have a single chunk allocated.
However, the goal of ReadFrom/WriteTo is *not* the ability to
exactly reproduce sparse files (in terms of the location of sparse holes),
but rather to provide an efficient way to create them.

File systems already impose their own restrictions on how the sparse file
will be created. Some filesystems (e.g., HFS+) don't support sparseness and
seeking forward simply causes the FS to write zeros. Other filesystems
have different chunk sizes, which will cause chunk allocations at boundaries
different from what was in the original sparse file. In either case,
it should not be a normal expectation of users that the location of holes
in sparse files exactly matches the source.

For users that really desire to have exact reproduction of sparse holes,
they can wrap os.File with their own io.WriteSeeker that discards the
final 1-byte write and uses File.Truncate to resize the file to the
correct size.

Other reasons we choose this approach over special-casing *os.File because:
	* The Reader already has special-case logic for io.Seeker
	* As much as possible, we want to decouple OS-specific logic from
	Reader and Writer.
	* This allows other abstractions over *os.File to also benefit from
	the "skip past holes" logic.
	* It is easier to test, since it is harder to mock an *os.File.

Updates #13548

Change-Id: I0a4f293bd53d13d154a946bc4a2ade28a6646f6a
Reviewed-on: https://go-review.googlesource.com/60872
Run-TryBot: Joe Tsai <thebrokentoaster@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

These are the last instructions missing to complete SSE3 support.

For reference what was missing was found by a tool [1]:

$ x86db-gogen list --extension SSE3 --not-known
ADDSUBPD xmmreg,xmmrm [rm: 66 0f d0 /r] PRESCOTT,SSE3,SO
ADDSUBPS xmmreg,xmmrm [rm: f2 0f d0 /r] PRESCOTT,SSE3,SO

[1] https://github.com/dlespiau/x86db

Fixes #20293

Change-Id: Ib5a91bf64dcc5282cdb60eae740ae52b4db16ebd
Reviewed-on: https://go-review.googlesource.com/42990
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ilya Tocar <ilya.tocar@intel.com>

As per golint's suggestions.

Change-Id: Ie0c6ad9aa5dc69966a279562a341c7b095c47ede
Reviewed-on: https://go-review.googlesource.com/64192
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Change-Id: If7ecdc57f190f647bfc673bde8e66b4ef12aa906
Reviewed-on: https://go-review.googlesource.com/64190Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

The current generator is a simple LSFR, which showed strong
correlation in higher bits, as manifested by fastrandn().

Change it with xorshift64+, which is slightly more complex,
has a larger state, but has a period of 2^64-1 and is much better
at statistical tests. The version used here is capable of
passing Diehard and even SmallCrush.

Speed is slightly worse but is probably insignificant:

name                old time/op  new time/op  delta
Fastrand-4          0.77ns ±12%  0.91ns ±21%  +17.31%  (p=0.048 n=5+5)
FastrandHashiter-4  13.6ns ±21%  15.2ns ±17%     ~     (p=0.160 n=6+5)
Fastrandn/2-4       2.30ns ± 5%  2.45ns ±15%     ~     (p=0.222 n=5+5)
Fastrandn/3-4       2.36ns ± 7%  2.45ns ± 6%     ~     (p=0.222 n=5+5)
Fastrandn/4-4       2.33ns ± 8%  2.61ns ±30%     ~     (p=0.126 n=6+5)
Fastrandn/5-4       2.33ns ± 5%  2.48ns ± 9%     ~     (p=0.052 n=6+5)

Fixes #21806

Change-Id: I013bb37b463fdfc229a7f324df8fe2da8d286f33
Reviewed-on: https://go-review.googlesource.com/62530
Run-TryBot: Michael Munday <mike.munday@ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>

Improves test coverage of the rules added in CL 63795 and would have
detected the bug fixed by CL 63950.

Change-Id: I107ee8d8e0b6684ce85b2446bd5018c5a03d608a
Reviewed-on: https://go-review.googlesource.com/64130Reviewed-by: Keith Randall <khr@golang.org>

The go compiler can generate better ARM code with those more
efficient FP instructions. And there is little improvement
in total but big improvement in special cases.

1. The size of pkg/linux_arm/math.a shrinks by 2.4%.

2. there is neither improvement nor regression in compilecmp benchmark.
name        old time/op       new time/op       delta
Template          2.32s ± 2%        2.32s ± 1%    ~     (p=1.000 n=9+10)
Unicode           1.32s ± 4%        1.32s ± 4%    ~     (p=0.912 n=10+10)
GoTypes           7.76s ± 1%        7.79s ± 1%    ~     (p=0.447 n=9+10)
Compiler          37.4s ± 2%        37.2s ± 2%    ~     (p=0.218 n=10+10)
SSA               84.8s ± 2%        85.0s ± 1%    ~     (p=0.604 n=10+9)
Flate             1.45s ± 2%        1.44s ± 2%    ~     (p=0.075 n=10+10)
GoParser          1.82s ± 1%        1.81s ± 1%    ~     (p=0.190 n=10+10)
Reflect           5.06s ± 1%        5.05s ± 1%    ~     (p=0.315 n=10+9)
Tar               2.37s ± 1%        2.37s ± 2%    ~     (p=0.912 n=10+10)
XML               2.56s ± 1%        2.58s ± 2%    ~     (p=0.089 n=10+10)
[Geo mean]        4.77s             4.77s       -0.08%

name        old user-time/op  new user-time/op  delta
Template          2.74s ± 2%        2.75s ± 2%    ~     (p=0.856 n=9+10)
Unicode           1.61s ± 4%        1.62s ± 3%    ~     (p=0.693 n=10+10)
GoTypes           9.55s ± 1%        9.49s ± 2%    ~     (p=0.056 n=9+10)
Compiler          45.9s ± 1%        45.8s ± 1%    ~     (p=0.345 n=9+10)
SSA                110s ± 1%         110s ± 1%    ~     (p=0.763 n=9+10)
Flate             1.68s ± 2%        1.68s ± 3%    ~     (p=0.616 n=10+10)
GoParser          2.14s ± 4%        2.14s ± 1%    ~     (p=0.825 n=10+9)
Reflect           5.95s ± 1%        5.97s ± 3%    ~     (p=0.951 n=9+10)
Tar               2.94s ± 3%        2.93s ± 2%    ~     (p=0.359 n=10+10)
XML               3.03s ± 3%        3.07s ± 6%    ~     (p=0.166 n=10+10)
[Geo mean]        5.76s             5.77s       +0.12%

name        old text-bytes    new text-bytes    delta
HelloSize         588kB ± 0%        588kB ± 0%    ~     (all equal)

name        old data-bytes    new data-bytes    delta
HelloSize        5.46kB ± 0%       5.46kB ± 0%    ~     (all equal)

name        old bss-bytes     new bss-bytes     delta
HelloSize        72.9kB ± 0%       72.9kB ± 0%    ~     (all equal)

name        old exe-bytes     new exe-bytes     delta
HelloSize        1.03MB ± 0%       1.03MB ± 0%    ~     (all equal)

3. The performance of Mandelbrot200 improves 15%, though little
   improvement in total.
name                     old time/op    new time/op    delta
BinaryTree17-4              41.7s ± 1%     41.7s ± 1%     ~     (p=0.264 n=29+23)
Fannkuch11-4                24.2s ± 0%     24.1s ± 1%   -0.13%  (p=0.050 n=30+30)
FmtFprintfEmpty-4           826ns ± 1%     824ns ± 1%   -0.24%  (p=0.038 n=25+30)
FmtFprintfString-4         1.38µs ± 1%    1.38µs ± 0%   -0.42%  (p=0.000 n=27+25)
FmtFprintfInt-4            1.46µs ± 1%    1.46µs ± 0%     ~     (p=0.060 n=30+23)
FmtFprintfIntInt-4         2.11µs ± 1%    2.08µs ± 0%   -1.04%  (p=0.000 n=30+30)
FmtFprintfPrefixedInt-4    2.23µs ± 1%    2.22µs ± 1%   -0.51%  (p=0.000 n=30+30)
FmtFprintfFloat-4          4.49µs ± 1%    4.48µs ± 1%   -0.22%  (p=0.004 n=26+30)
FmtManyArgs-4              8.06µs ± 1%    8.12µs ± 1%   +0.68%  (p=0.000 n=25+30)
GobDecode-4                 104ms ± 1%     104ms ± 2%     ~     (p=0.362 n=29+29)
GobEncode-4                92.9ms ± 1%    92.8ms ± 2%     ~     (p=0.786 n=30+30)
Gzip-4                      4.12s ± 1%     4.12s ± 1%     ~     (p=0.314 n=30+30)
Gunzip-4                    602ms ± 1%     603ms ± 1%     ~     (p=0.164 n=30+30)
HTTPClientServer-4          659µs ± 1%     655µs ± 2%   -0.64%  (p=0.006 n=25+28)
JSONEncode-4                234ms ± 1%     235ms ± 1%   +0.29%  (p=0.050 n=30+30)
JSONDecode-4                912ms ± 0%     911ms ± 0%     ~     (p=0.385 n=18+24)
Mandelbrot200-4            49.2ms ± 0%    41.7ms ± 0%  -15.35%  (p=0.000 n=25+27)
GoParse-4                  46.3ms ± 1%    46.3ms ± 2%     ~     (p=0.572 n=30+30)
RegexpMatchEasy0_32-4      1.29µs ± 1%    1.27µs ± 0%   -1.59%  (p=0.000 n=30+30)
RegexpMatchEasy0_1K-4      7.62µs ± 4%    7.71µs ± 3%     ~     (p=0.074 n=30+30)
RegexpMatchEasy1_32-4      1.31µs ± 0%    1.30µs ± 1%   -0.71%  (p=0.000 n=23+30)
RegexpMatchEasy1_1K-4      10.3µs ± 3%    10.3µs ± 5%     ~     (p=0.105 n=30+30)
RegexpMatchMedium_32-4     2.06µs ± 1%    2.06µs ± 1%     ~     (p=0.100 n=30+30)
RegexpMatchMedium_1K-4      533µs ± 1%     534µs ± 1%     ~     (p=0.254 n=29+30)
RegexpMatchHard_32-4       28.9µs ± 0%    28.9µs ± 0%     ~     (p=0.154 n=30+30)
RegexpMatchHard_1K-4        868µs ± 1%     867µs ± 0%     ~     (p=0.729 n=30+23)
Revcomp-4                  66.9ms ± 1%    67.2ms ± 2%     ~     (p=0.102 n=28+29)
Template-4                  1.07s ± 1%     1.06s ± 1%   -0.53%  (p=0.000 n=30+30)
TimeParse-4                7.07µs ± 1%    7.01µs ± 0%   -0.85%  (p=0.000 n=30+25)
TimeFormat-4               13.1µs ± 0%    13.2µs ± 1%   +0.77%  (p=0.000 n=27+27)
[Geo mean]                  721µs          716µs        -0.70%

name                     old speed      new speed      delta
GobDecode-4              7.38MB/s ± 1%  7.37MB/s ± 2%     ~     (p=0.399 n=29+29)
GobEncode-4              8.26MB/s ± 1%  8.27MB/s ± 2%     ~     (p=0.790 n=30+30)
Gzip-4                   4.71MB/s ± 1%  4.71MB/s ± 1%     ~     (p=0.885 n=30+30)
Gunzip-4                 32.2MB/s ± 1%  32.2MB/s ± 1%     ~     (p=0.190 n=30+30)
JSONEncode-4             8.28MB/s ± 1%  8.25MB/s ± 1%     ~     (p=0.053 n=30+30)
JSONDecode-4             2.13MB/s ± 0%  2.12MB/s ± 1%     ~     (p=0.072 n=18+30)
GoParse-4                1.25MB/s ± 1%  1.25MB/s ± 2%     ~     (p=0.863 n=30+30)
RegexpMatchEasy0_32-4    24.8MB/s ± 0%  25.2MB/s ± 1%   +1.61%  (p=0.000 n=30+30)
RegexpMatchEasy0_1K-4     134MB/s ± 4%   133MB/s ± 3%     ~     (p=0.074 n=30+30)
RegexpMatchEasy1_32-4    24.5MB/s ± 0%  24.6MB/s ± 1%   +0.72%  (p=0.000 n=23+30)
RegexpMatchEasy1_1K-4    99.1MB/s ± 3%  99.8MB/s ± 5%     ~     (p=0.105 n=30+30)
RegexpMatchMedium_32-4    483kB/s ± 1%   487kB/s ± 1%   +0.83%  (p=0.002 n=30+30)
RegexpMatchMedium_1K-4   1.92MB/s ± 1%  1.92MB/s ± 1%     ~     (p=0.058 n=30+30)
RegexpMatchHard_32-4     1.10MB/s ± 0%  1.11MB/s ± 0%     ~     (p=0.804 n=30+30)
RegexpMatchHard_1K-4     1.18MB/s ± 0%  1.18MB/s ± 0%     ~     (all equal)
Revcomp-4                38.0MB/s ± 1%  37.8MB/s ± 2%     ~     (p=0.098 n=28+29)
Template-4               1.82MB/s ± 1%  1.83MB/s ± 1%   +0.55%  (p=0.000 n=29+29)
[Geo mean]               6.79MB/s       6.79MB/s        +0.09%

Change-Id: Ia91991c2c5c59c5df712de85a83b13a21c0a554b
Reviewed-on: https://go-review.googlesource.com/63770
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>