Construct better initial partitions by recursively comparing values and
their arguments.  This saves one second on compile of arithConst_ssa.go
(4.3s to 3.3s) and shows a 3-5% increase with compilebench.

name       old time/op     new time/op     delta
Template       266ms ± 3%      253ms ± 4%  -5.08%          (p=0.032 n=5+5)
GoTypes        927ms ± 3%      885ms ± 2%  -4.55%          (p=0.016 n=5+5)
Compiler       3.91s ± 3%      3.73s ± 2%  -4.49%          (p=0.008 n=5+5)
MakeBash       31.6s ± 1%      30.5s ± 3%  -3.51%          (p=0.016 n=5+5)

Change-Id: I6ede31ff459131ccfed69531acfbd06b19837700
Reviewed-on: https://go-review.googlesource.com/19838Reviewed-by: David Chase <drchase@google.com>

Helps keep line numbers around for debugging, particularly
for break and continue statements (which often compile
down to nothing).

Update #14379

Change-Id: I6ea06aa887b0450d9ba4f11e319e5c263f5a98ba
Reviewed-on: https://go-review.googlesource.com/19848Reviewed-by: David Chase <drchase@google.com>

Saves about 2k for binaries in pkg/tool/linux_amd64.
Also useful when opt runs after cse (as in 12960) which reorders
arguments for commutative operations such as Add64.

Change-Id: I49ad53afa53db9736bd35c425f4fb35fb511fd63
Reviewed-on: https://go-review.googlesource.com/19827
Run-TryBot: Alexandru Moșoi <alexandru@mosoi.ro>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: Keith Randall <khr@golang.org>

Semi-regular merge from tip to dev.ssa.

Change-Id: If7d2269f267bcbc0ecd3a483d349951044470e3f

name                        old time/op  new time/op  delta
DecodeValidASCII-4          94.7ns ± 1%  87.4ns ± 1%  -7.71%  (p=0.000 n=10+9)
DecodeValidJapaneseChars-4  91.0ns ± 2%  84.8ns ± 0%  -6.77%  (p=0.000 n=9+10)
DecodeRune-4                16.5ns ± 0%  16.6ns ± 2%    ~     (p=0.108 n=9+10)

For #6957

Change-Id: I618c15c2a42ef7ec6a5cd163b7c3f1a65ca4ad01
Reviewed-on: https://go-review.googlesource.com/19826Reviewed-by: Rob Pike <r@golang.org>

This reverts commit f28bbb77.

Change-Id: I82fb81dcff3ddcaefef72949f1ef3a41bcd22301
Reviewed-on: https://go-review.googlesource.com/19849
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>

The previous Happy Eyeballs implementation would intentionally leak
connections, because dialTCP could not be reliably terminated upon
losing the race.

Now that dialTCP supports cancelation (plan9 excluded), dialParallel can
wait for responses from both the primary and fallback racers, strictly
before returning control to the caller.

In dial_test.go, we no longer need Sleep to avoid leaks.
Also, fix a typo in the Benchmark IPv4 address.

Updates #11225
Fixes #14279

Change-Id: Ibf3fe5c7ac2f7a438c1ab2cdb57032beb8bc27b5
Reviewed-on: https://go-review.googlesource.com/19390Reviewed-by: Mikio Hara <mikioh.mikioh@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

The () parentheses grouped wrongly. Removed them completely in
favor of separate 2- and 3-index slice alternatives which is
clearer.

Fixes #14477.

Change-Id: I0b7521ac912130d9ea8740b8793b3b88e2609418
Reviewed-on: https://go-review.googlesource.com/19853Reviewed-by: Ian Lance Taylor <iant@golang.org>

While investigating the differences between 19710 (remove
tautological controls) and 12960 (bounds and nil propagation)
I observed that part of the wins of 19710 come from missed
opportunities for deadcode elimination due to phis.
See for example runtime.stackcacherelease. 19710 happens much
later than 12960 and has more chances to eliminate bounds.

Size of pkg/tool/linux_amd64/* excluding compile:

-this -12960 95882248
+this -12960 95880120
-this +12960 95581512
+this +12960 95555224

This change saves about 25k.

Change-Id: Id2f4e55fc92b71595842ce493c3ed527d424fe0e
Reviewed-on: https://go-review.googlesource.com/19728Reviewed-by: David Chase <drchase@google.com>
Run-TryBot: Alexandru Moșoi <alexandru@mosoi.ro>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Makes godoc 10KB smaller.
For #6853.

Change-Id: Id54bd8c82cb2a1ba11d2d724e3107f73024b19d9
Reviewed-on: https://go-review.googlesource.com/19696
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Found running go vet on the package. It barks that
	regexp/backtrack.go:257: unreachable code
	regexp/backtrack.go:302: unreachable code

For #11041

Change-Id: I0f5ba0d6183108fba3d144991b826273db0ffb09
Reviewed-on: https://go-review.googlesource.com/19824Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Current code does not print any response headers from httputil.DumpResponse().

   PUT /miniocloud/new-file HTTP/1.1
   Host: s3.amazonaws.com
   User-Agent: Go-http-client/1.1
   Content-Length: 11
   Accept-Encoding: gzip

   HTTP/1.1 200 OK

With this fix we get an appropriate output for httputil.DumpResponse().

   PUT /miniocloud/new-file HTTP/1.1
   Host: s3.amazonaws.com
   User-Agent: Go-http-client/1.1
   Content-Length: 11
   Accept-Encoding: gzip

   HTTP/1.1 200 OK
   Content-Length: 0
   Date: Thu, 14 Jan 2016 03:04:42 GMT
   Etag: "3e25960a79dbc69b674cd4ec67a72c62"
   Server: AmazonS3
   X-Amz-Id-2: qnXyH6sknlovV0Myy3emFAXTNtI/sQIcu1ZXNq/6wd17K32tQ7WNGB1qb3nzCpW2DhfeZ/MbWfw=
   X-Amz-Request-Id: 8422EACB0CC492BD

Fixes #13942

Change-Id: Ida063cc3524a96170d8a837893f7c9f49b6cf98e
Reviewed-on: https://go-review.googlesource.com/18624Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Change-Id: I6035941df8b0de6aeaf6c05df7257bcf6e9191fe
Reviewed-on: https://go-review.googlesource.com/19320Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

For #6957

Change-Id: Ic497c12f33efc933e9fe81f6cd1b2a0a01abbabf
Reviewed-on: https://go-review.googlesource.com/19820
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

util.go was originally added in golang.org/cl/4851, and later moved to
its current location in golang.org/cl/10287.

Change-Id: I10b4941d42ae1ff2e78990c497c1347bbbae4e3d
Reviewed-on: https://go-review.googlesource.com/19851Reviewed-by: David Crawshaw <crawshaw@golang.org>

Change-Id: Ib413b0cb16405965455d7764a8c4a22bf431389b
Reviewed-on: https://go-review.googlesource.com/19850
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>

The upper bits of 8/16/32 bit constants are undefined.  We need to
truncate in order to prevent x86.oclass misidentifying the size of the
constant.

Fixes #14389

Change-Id: I3e5ff79cd904376572a93f489ba7e152a5cb6e60
Reviewed-on: https://go-review.googlesource.com/19740Reviewed-by: Keith Randall <khr@golang.org>

Pass lexer around so state is accessible and dependency is explicit.
In the process remove EOF -> '\n' conversion that has to be corrected
for when reporting errors.

Change-Id: If95564b70e7484dedc1f5348e585cd19acbc1243
Reviewed-on: https://go-review.googlesource.com/19819
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

Fixes #14475.

Change-Id: I1b5b0a9793a417572ec55f313185d03ad5ae9d01
Reviewed-on: https://go-review.googlesource.com/19846Reviewed-by: Robert Griesemer <gri@golang.org>

Loads of stores from the same pointer with compatible types
can be replaced with a copy.

Change-Id: I514b3ed8e5b6a9c432946880eac67a51b1607932
Reviewed-on: https://go-review.googlesource.com/19743
Run-TryBot: Todd Neal <todd@tneal.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>

They do the same thing, except memequal also has the short-circuit
check if the two pointers are equal.

A) We might as well always do the short-circuit check, it is only 2 instructions.
B) The extra function call (memequal->memeq) is expensive.

benchmark                 old ns/op     new ns/op     delta
BenchmarkArrayEqual-8     8.56          5.31          -37.97%

No noticeable affect on the former memeq user (maps).

Fixes #14302

Change-Id: I85d1ada59ed11e64dd6c54667f79d32cc5f81948
Reviewed-on: https://go-review.googlesource.com/19843
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

A comment existed referencing RC4 coming before AES because of it's
vulnerability to the Lucky 13 attack. This clarifies that the Lucky 13 attack
only effects AES-CBC, and not AES-GCM.

Fixes #14474

Change-Id: Idcb07b5e0cdb0f9257cf75abea60129ba495b5f5
Reviewed-on: https://go-review.googlesource.com/19845Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

The structure of the code meant that an embedded field was never
checked for export status. We need to check the name of the type,
which is either of type T or type *T, and T might be unexported.

Fixes #14356.

Change-Id: I56f468e9b8ae67e9ed7509ed0b91d860507baed2
Reviewed-on: https://go-review.googlesource.com/19701Reviewed-by: Robert Griesemer <gri@golang.org>

It's not needed on other OSes.

Change-Id: Ia6b13510585392a7062374806527d33876beba2a
Reviewed-on: https://go-review.googlesource.com/19818
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Change-Id: I7414d2fab18ae6e7e7c50f8697ec64d38290f409
Reviewed-on: https://go-review.googlesource.com/19817
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Cuts 20k off cmd/go and 32k off golang.org/x/tools/cmd/godoc, approx 0.15% each.

For #6853 and #9930

Change-Id: Ic510b76b80a9153b1ede7b3533d2dbc16caa5c63
Reviewed-on: https://go-review.googlesource.com/19768
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>

When visiting the AST to add counters, there are special cases in which
the code calls cuts the walking short by returning nil. In some cases
certain nodes are ignored, e.g. Init and Cond inside IfStmt.

The fix is to explicitly walk all the children nodes (not only
Body and Else) when cutting the current walk. Similar approach
was taken with SwitchStmt and TypeSwitchStmt.

While the existing test code doesn't handle different counters in the
same line, the generated HTML report does it correctly (because it takes
column into account).

The previous behavior caused lines in function literals to not be
tracked when those literals were inside Init or Cond of an IfStmt for
example.

Fixes #14039.

Change-Id: Iad591363330843ad833bd79a0388d709c8d0c8aa
Reviewed-on: https://go-review.googlesource.com/19775Reviewed-by: Rob Pike <r@golang.org>

These files were not added to the repo. They contain conversion
routines and corresponding tests not used by the compiler and
thus are technically not needed.

However, future changes to math/big (and corresponding updates
of this vendored version) may require these files to exist.
Add them to avoid unnecessary confusion.

Change-Id: Ie390fb54f499463b2bba2fdc084967539afbeeb3
Reviewed-on: https://go-review.googlesource.com/19730Reviewed-by: Alan Donovan <adonovan@google.com>

Benchmarked using compilebench on a quiet
but rather old OS X laptop.

Benchmarks from others would be welcome,
since the numbers look too good to be true.

name      old time/op    new time/op    delta
Template     331ms ± 9%     303ms ± 4%   -8.25%  (p=0.000 n=24+24)
GoTypes      946ms ± 4%     888ms ± 3%   -6.17%  (p=0.000 n=24+25)
Compiler     3.20s ± 1%     3.10s ± 2%   -3.07%  (p=0.000 n=24+25)

name      old alloc/op   new alloc/op   delta
Template    72.5MB ± 0%    61.8MB ± 0%  -14.76%  (p=0.000 n=25+24)
GoTypes      224MB ± 0%     189MB ± 0%  -15.65%  (p=0.000 n=25+25)
Compiler     695MB ± 0%     561MB ± 0%  -19.26%  (p=0.000 n=25+25)

name      old allocs/op  new allocs/op  delta
Template      498k ± 0%      497k ± 0%   -0.21%  (p=0.000 n=25+23)
GoTypes      1.47M ± 0%     1.47M ± 0%   -0.25%  (p=0.000 n=25+25)
Compiler     4.09M ± 0%     4.08M ± 0%   -0.18%  (p=0.000 n=25+23)

Change-Id: I2394bc748128d721863453257fa5756c410f7898
Reviewed-on: https://go-review.googlesource.com/19771Reviewed-by: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Replaced comparison based on (*Type).String() with an
allocation-free structural comparison.  Roughly doubles
speed of CSE, also reduces allocations.

Checked that roughly the same number of CSEs were detected
during make.bash (about a million) and that "new" CSEs
were caused by the effect described above.

Change-Id: Id205a9f6986efd518043e12d651f0b01206aeb1b
Reviewed-on: https://go-review.googlesource.com/19471Reviewed-by: Keith Randall <khr@golang.org>

* If a operation is commutative order the parameters
in a canonical way.

Size of pkg/tool/linux_amd64/* excluding compile:
before: 95882288
 after: 95868152
change: 14136 ~0.015%

I tried something similar with Leq and Geq, but the results were
not great because it confuses the 'lowered cse' pass too much
which can no longer remove redundant comparisons from IsInBounds.

Change-Id: I2f928663a11320bfc51c7fa47e384b7411c420ba
Reviewed-on: https://go-review.googlesource.com/19727Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: Alexandru Moșoi <alexandru@mosoi.ro>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Spotted a minor source of excess allocation in the register
allocator.  Rearranged the dominator tree code to pull its
scratch memory from a reused buffer attached to Config.

Change-Id: I6da6e7b112f7d3eb1fd00c58faa8214cdea44e38
Reviewed-on: https://go-review.googlesource.com/19450Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Add an initial cse pass that only operates on zero argument
values.  This removes the need for a special case in cse for removing
OpSB and speeds up arithConst_ssa.go compilation by 9% while slowing
"test -c net/http" by 1.5%.

Change-Id: Id1500482485426f66c6c2eba75eeaf4f19c8a889
Reviewed-on: https://go-review.googlesource.com/19454
Run-TryBot: Todd Neal <todd@tneal.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>

Also eliminates per-maptype hiter and hmap types, since they're not
really needed anyway.  Update packages reflect and runtime
accordingly.

Reduces golang.org/x/tools/cmd/godoc's text segment by ~170kB:

   text	   data	    bss	    dec	    hex	filename
13085702	 140640	 151520	13377862	 cc2146	godoc.before
12915382	 140640	 151520	13207542	 c987f6	godoc.after

Updates #6853.

Change-Id: I948b2bc1f22d477c1756204996b4e3e1fb568d81
Reviewed-on: https://go-review.googlesource.com/16610Reviewed-by: Keith Randall <khr@golang.org>

These functions are really simple, the overhead of calling
them (in both time and code size) is larger than the inlined versions.

Reorganize how the nil case in a type switch is handled, as we have
to check for nil explicitly now anyway.

Saves about 0.8% in the binary size of the go tool.

Change-Id: I8501b62d72fde43650b79f52b5f699f1fbd0e7e7
Reviewed-on: https://go-review.googlesource.com/19814
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>

This adds a test case with aliased pointers to ensure modifications to
dse don't remove valid stores.

Change-Id: I143653250f46a403835218ec685bcd336d5087ef
Reviewed-on: https://go-review.googlesource.com/19795Reviewed-by: Keith Randall <khr@golang.org>

Previously, given two Nodes n1 and n2 of different non-PAUTO classes
(e.g., PPARAM and PPARAMOUT), cmpstackvarlt(n1, n2) and
cmpstackvarlt(n2, n1) both returned true, which is nonsense.

This doesn't seem to cause any visible miscompilation problems, but
notably fixing it does cause toolstash/buildall to fail.

Change-Id: I33b2c66e902c5eced875d8fbf18b7cfdc81e8aed
Reviewed-on: https://go-review.googlesource.com/19778
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Change-Id: Ibbfae20cab48163f22d661604ef730705f2b97ba
Reviewed-on: https://go-review.googlesource.com/19661
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Order's "temp" and "free" fields use NodeLists in a rather
non-idiomatic way.  Instead of using the "list" or "concat" functions,
it manipulates them directly and without the normal invariants (e.g.,
it doesn't maintain the "End" field).

Rather than convert it to more typical usage, just replace with a
slice, which ends up much simpler anyway.

Passes toolstash/buildall.

Change-Id: Ibd0f24324bd674c0d5bb1bc40d073b01e7824ad5
Reviewed-on: https://go-review.googlesource.com/19776
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Change-Id: I6cb8ac7b59812e82111ab3b0f8303ab8194a5129
Reviewed-on: https://go-review.googlesource.com/19791Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>