delta/go-git.git/test/checkbce.go, branch dev.typeparams

cmd/compile: fix ordering for short-circuiting ops

2019-03-06T20:04:07+00:00

Make sure the side effects inside short-circuited operations (&& and ||)
happen correctly.

Before this CL, we attached the side effects to the node itself using
exprInPlace. That caused other side effects in sibling expressions
to get reordered with respect to the short circuit side effect.

Instead, rewrite a && b like:

r := a
if r {
  r = b
}

That code we can keep correctly ordered with respect to other
side-effects extracted from part of a big expression.

exprInPlace seems generally unsafe. But this was the only case where
exprInPlace is called not at the top level of an expression, so I
don't think the other uses can actually trigger an issue (there can't
be a sibling expression). TODO: maybe those cases don't need "in
place", and we can retire that function generally.

This CL needed a small tweak to the SSA generation of OIF so that the
short circuit optimization still triggers. The short circuit optimization
looks for triangle but not diamonds, so don't bother allocating a block
if it will be empty.

Go 1 benchmarks are in the noise.

Fixes #30566

Change-Id: I19c04296bea63cbd6ad05f87a63b005029123610
Reviewed-on: https://go-review.googlesource.com/c/go/+/165617
Run-TryBot: Keith Randall 
TryBot-Result: Gobot Gobot 
Reviewed-by: David Chase

test: restore binary.BigEndian use in checkbce

2018-09-24T21:20:51+00:00

CL 136855 removed the encoding/binary dependency from the checkbce.go
test by defining a local Uint64 to fix the noopt builder; then a more
general mechanism to skip tests on the noopt builder was introduced in
CL 136898, so we can now restore the binary.Uint64 calls in testbce.

Change-Id: I3efbb41be0bfc446a7e638ce6a593371ead2684f
Reviewed-on: https://go-review.googlesource.com/137056
Run-TryBot: Alberto Donizetti 
Reviewed-by: Giovanni Bajo 
Reviewed-by: Brad Fitzpatrick 
TryBot-Result: Gobot Gobot

test: skip some tests on noopt builder

2018-09-24T20:56:48+00:00

Adds a new build tag "gcflags_noopt" that can be used in test/*.go
tests.

Fixes #27833

Change-Id: I4ea0ccd9e9e58c4639de18645fec81eb24a3a929
Reviewed-on: https://go-review.googlesource.com/136898
Run-TryBot: Brad Fitzpatrick 
TryBot-Result: Gobot Gobot 
Reviewed-by: Keith Randall

test: fix bcecheck test on noopt builder

2018-09-24T16:54:52+00:00

The noopt builder is configured by setting GO_GCFLAGS=-N -l, but the
test/run.go test harness doesn't look at GO_GCFLAGS when processing
"errorcheck" files, it just calls compile:

  cmdline := []string{goTool(), "tool", "compile", /* etc */}

This is working as intended, since it makes the tests more robust and
independent from the environment; errorcheck files are supposed to set
additional building flags, when needed, like in:

  // errorcheck -0 -N -l

The test/bcecheck.go test used to work on the noopt builder (even if
bce is not active on -N -l) because the test was auto-contained and
the file always compiled with optimizations enabled.

In CL 107355, a new bce test dependent on an external package
(encoding.binary) was added. On the noopt builder the external package
is built using -N -l, and this causes a test failure that broke the
noopt builder:

  https://build.golang.org/log/b2be319536285e5807ee9d66d6d0ec4d57433768

To reproduce the failure, one can do:

  $ go install -a -gcflags="-N -l" std
  $ go run run.go -- checkbce.go

This change fixes the noopt builder breakage by removing the bce test
dependency on encoding/binary by defining a local Uint64() function to
be used in the test.

Change-Id: Ife71aab662001442e715c32a0b7d758349a63ff1
Reviewed-on: https://go-review.googlesource.com/136855
Reviewed-by: Brad Fitzpatrick

cmd/compile: add testcase for #24876

2018-09-02T10:34:51+00:00

This is still not fixed, the testcase reflects that there are still
a few boundchecks. Let's fix the good alternative with an explicit
test though.

Updates #24876

Change-Id: I4da35eb353e19052bd7b69ea6190a69ced8b9b3d
Reviewed-on: https://go-review.googlesource.com/107355
Reviewed-by: Brad Fitzpatrick 
Run-TryBot: Giovanni Bajo 
TryBot-Result: Gobot Gobot

test: add missing copyright header to checkbce.go

2017-05-18T00:05:25+00:00

Change-Id: Iafeb8e033c876f482caa17cca414fe13b0fadb12
Reviewed-on: https://go-review.googlesource.com/43613
Run-TryBot: Ian Lance Taylor 
TryBot-Result: Gobot Gobot 
Reviewed-by: Dave Cheney

cmd/compile: improve generic rules for BCE based on AND operations.

2017-03-04T16:13:07+00:00

Match more patterns generated by the compiler where the index for
a bound check is bounded through a AND operation, with different
register sizes.

These rules trigger a dozen of times in a bootstrap.

Change-Id: Ic9fff16f21d08580f19a366c3ee1a372e58357d1
Reviewed-on: https://go-review.googlesource.com/37442
TryBot-Result: Gobot Gobot 
Reviewed-by: Keith Randall

cmd/compile: use len(s)<=cap(s) to remove more bounds checks

2017-02-02T17:45:58+00:00

When we discover a relation x <= len(s), also discover the relation
x <= cap(s).  That way, in situations like:

a := s[x:]  // tests 0 <= x <= len(s)
b := s[:x]  // tests 0 <= x <= cap(s)

the second check can be eliminated.

Fixes #16813

Change-Id: Ifc037920b6955e43bac1a1eaf6bac63a89cfbd44
Reviewed-on: https://go-review.googlesource.com/33633
Run-TryBot: Keith Randall 
TryBot-Result: Gobot Gobot 
Reviewed-by: Alexandru Moșoi 
Reviewed-by: David Chase

cmd/compile: optimize integer "in range" expressions

2016-08-25T03:49:16+00:00

Use unsigned comparisons to reduce from
two comparisons to one for integer "in range"
checks, such as a <= b && b < c.
We already do this for bounds checks.
Extend it to user code.

This is much easier to do in the front end than SSA.
A back end optimization would be more powerful,
but this is a good start.

This reduces the power of some of SSA prove
inferences (#16653), but those regressions appear
to be rare and not worth holding this CL for.

Fixes #15844.
Fixes #16697.

strconv benchmarks:

name                          old time/op  new time/op   delta
Atof64Decimal-8               41.4ns ± 3%   38.9ns ± 2%   -5.89%  (p=0.000 n=24+25)
Atof64Float-8                 48.5ns ± 0%   46.8ns ± 3%   -3.64%  (p=0.000 n=20+23)
Atof64FloatExp-8              97.7ns ± 4%   93.5ns ± 1%   -4.25%  (p=0.000 n=25+20)
Atof64Big-8                    187ns ± 8%    162ns ± 2%  -13.54%  (p=0.000 n=24+22)
Atof64RandomBits-8             250ns ± 6%    233ns ± 5%   -6.76%  (p=0.000 n=25+25)
Atof64RandomFloats-8           160ns ± 0%    152ns ± 0%   -5.00%  (p=0.000 n=21+22)
Atof32Decimal-8               41.1ns ± 1%   38.7ns ± 2%   -5.86%  (p=0.000 n=24+24)
Atof32Float-8                 46.1ns ± 1%   43.5ns ± 3%   -5.63%  (p=0.000 n=21+24)
Atof32FloatExp-8               101ns ± 4%    100ns ± 2%   -1.59%  (p=0.000 n=24+23)
Atof32Random-8                 136ns ± 3%    133ns ± 3%   -2.83%  (p=0.000 n=22+22)
Atoi-8                        33.8ns ± 3%   30.6ns ± 3%   -9.51%  (p=0.000 n=24+25)
AtoiNeg-8                     31.6ns ± 3%   29.1ns ± 2%   -8.05%  (p=0.000 n=23+24)
Atoi64-8                      48.6ns ± 1%   43.8ns ± 1%   -9.81%  (p=0.000 n=20+23)
Atoi64Neg-8                   47.1ns ± 4%   42.0ns ± 2%  -10.83%  (p=0.000 n=25+25)
FormatFloatDecimal-8           177ns ± 9%    178ns ± 6%     ~     (p=0.460 n=25+25)
FormatFloat-8                  282ns ± 6%    282ns ± 3%     ~     (p=0.954 n=25+22)
FormatFloatExp-8               259ns ± 7%    255ns ± 6%     ~     (p=0.089 n=25+24)
FormatFloatNegExp-8            253ns ± 6%    254ns ± 6%     ~     (p=0.941 n=25+24)
FormatFloatBig-8               340ns ± 6%    341ns ± 8%     ~     (p=0.600 n=22+25)
AppendFloatDecimal-8          79.4ns ± 0%   80.6ns ± 6%     ~     (p=0.861 n=20+25)
AppendFloat-8                  175ns ± 3%    174ns ± 0%     ~     (p=0.722 n=25+20)
AppendFloatExp-8               142ns ± 4%    142ns ± 2%     ~     (p=0.948 n=25+24)
AppendFloatNegExp-8            137ns ± 2%    138ns ± 2%   +0.70%  (p=0.001 n=24+25)
AppendFloatBig-8               218ns ± 3%    218ns ± 4%     ~     (p=0.596 n=25+25)
AppendFloatBinaryExp-8        80.0ns ± 4%   78.0ns ± 1%   -2.43%  (p=0.000 n=24+21)
AppendFloat32Integer-8        82.3ns ± 3%   79.3ns ± 4%   -3.69%  (p=0.000 n=24+25)
AppendFloat32ExactFraction-8   143ns ± 2%    143ns ± 0%     ~     (p=0.177 n=23+19)
AppendFloat32Point-8           175ns ± 3%    175ns ± 3%     ~     (p=0.062 n=24+25)
AppendFloat32Exp-8             139ns ± 2%    137ns ± 4%   -1.05%  (p=0.001 n=24+24)
AppendFloat32NegExp-8          134ns ± 0%    137ns ± 4%   +2.06%  (p=0.000 n=22+25)
AppendFloat64Fixed1-8         97.8ns ± 0%   98.6ns ± 3%     ~     (p=0.711 n=20+25)
AppendFloat64Fixed2-8          110ns ± 3%    110ns ± 5%   -0.45%  (p=0.037 n=24+24)
AppendFloat64Fixed3-8          102ns ± 3%    102ns ± 3%     ~     (p=0.684 n=24+24)
AppendFloat64Fixed4-8          112ns ± 3%    110ns ± 0%   -1.43%  (p=0.000 n=25+18)
FormatInt-8                   3.18µs ± 4%   3.10µs ± 6%   -2.54%  (p=0.001 n=24+25)
AppendInt-8                   1.81µs ± 5%   1.80µs ± 5%     ~     (p=0.648 n=25+25)
FormatUint-8                   812ns ± 6%    816ns ± 6%     ~     (p=0.777 n=25+25)
AppendUint-8                   536ns ± 4%    538ns ± 3%     ~     (p=0.798 n=20+22)
Quote-8                        605ns ± 6%    602ns ± 9%     ~     (p=0.573 n=25+25)
QuoteRune-8                   99.5ns ± 8%  100.2ns ± 7%     ~     (p=0.432 n=25+25)
AppendQuote-8                  361ns ± 3%    363ns ± 4%     ~     (p=0.085 n=25+25)
AppendQuoteRune-8             23.3ns ± 3%   22.4ns ± 2%   -3.79%  (p=0.000 n=25+24)
UnquoteEasy-8                  146ns ± 4%    145ns ± 5%     ~     (p=0.112 n=24+24)
UnquoteHard-8                  804ns ± 6%    771ns ± 6%   -4.10%  (p=0.000 n=25+24)

Change-Id: Ibd384e46e90f1cfa40503c8c6352a54c65b72980
Reviewed-on: https://go-review.googlesource.com/27652
Run-TryBot: Josh Bleecher Snyder 
Reviewed-by: Matthew Dempsky 
TryBot-Result: Gobot Gobot

cmd/compile: bce when max and limit are consts

2016-04-11T16:01:22+00:00

Removes 49 more bound checks in make.bash. For example:

var a[100]int
for i := 0; i < 50; i++ {
  use a[i+25]
}

Change-Id: I85e0130ee5d07f0ece9b17044bba1a2047414ce7
Reviewed-on: https://go-review.googlesource.com/21379
Reviewed-by: David Chase 
Run-TryBot: Alexandru Moșoi 
TryBot-Result: Gobot Gobot