Commit Graph

370 Commits

Author SHA1 Message Date
Daniel Martí a265f2e90e go/printer: indent lone comments in composite lits
If a composite literal contains any comments on their own lines without
any elements, the printer would unindent the comments.

The comments in this edge case are written when the closing '}' is
written. Indent and outdent first so that the indentation is
interspersed before the comment is written.

Also note that the go/printer golden tests don't show the exact same
behaviour that gofmt does. Added a TODO to figure this out in a separate
CL.

While at it, ensure that the tree conforms to gofmt. The changes are
unrelated to this indentation fix, however.

Fixes #22355.

Change-Id: I5ac25ac6de95a236f1e123479127cc4dd71e93fe
Reviewed-on: https://go-review.googlesource.com/74232
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
Reviewed-by: Robert Griesemer <gri@golang.org>
2017-11-15 18:48:48 +00:00
Brian Kessler 2955a8a6cc math/big: clarify comment on lehmerGCD overflow
A clarifying comment was added to indicate that overflow of a
single Word is not possible in the single digit calculation.
Lehmer's paper includes a proof of the bounds on the size of the
cosequences (u0, u1, u2, v0, v1, v2).

Change-Id: I98127a07aa8f8fe44814b74b2bc6ff720805194b
Reviewed-on: https://go-review.googlesource.com/77451
Reviewed-by: Robert Griesemer <gri@golang.org>
2017-11-14 17:32:39 +00:00
Filippo Valsorda ef0e2af7b0 math/big: add security warning to (*Int).Rand
Change-Id: I22a67733aa2d07298e124077654c9b1473802100
Reviewed-on: https://go-review.googlesource.com/76012
Reviewed-by: Aliaksandr Valialkin <valyala@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2017-11-06 15:55:31 +00:00
Tobias Klauser 89bcbf40b8 math/bits: add examples for right rotation
Right rotation is achieved using negative k in RotateLeft*(x, k). Add
examples demonstrating that functionality.

Change-Id: I15dab159accd2937cb18d3fa8ca32da8501567d3
Reviewed-on: https://go-review.googlesource.com/75371
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
2017-11-03 20:12:07 +00:00
Lynn Boger 3860478b42 math: implement asm modf for ppc64x
This change adds an asm implementations modf for ppc64x.

Improvements:

BenchmarkModf-16               7.48          6.26          -16.31%

Updates: #21390

Change-Id: I9c4f3213688e3e8842d050840dc04fc9c0bf6ce4
Reviewed-on: https://go-review.googlesource.com/74411
Run-TryBot: Lynn Boger <laboger@linux.vnet.ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Michael Munday <mike.munday@ibm.com>
2017-11-02 13:24:32 +00:00
griesemer 85c32c3744 math/big: implement CmpAbs
Fixes #22473.

Change-Id: Ie886dfc8b5510970d6d63ca6472c73325f6f2276
Reviewed-on: https://go-review.googlesource.com/74971
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Martin Möhrmann <moehrmann@google.com>
2017-11-01 18:17:49 +00:00
Alberto Donizetti 856dccb175 math/big: avoid unnecessary Newton iteration in Float.Sqrt
An initial draft of the Newton code for Float.Sqrt was structured like
this:

  for condition
    // do Newton iteration..
    prec *= 2

since prec, at the end of the loop, was double the precision used in
the last Newton iteration, the termination condition was set to
2*limit. The code was later rewritten in the form

  for condition
    prec *= 2
    // do Newton iteration..

but condition was not updated, and it's still 2*limit, which is about
double what we actually need, and is triggering the execution of an
additional, and unnecessary, Newton iteration.

This change adjusts the Newton termination condition to the (correct)
value of z.prec, plus 32 guard bits as a safety margin.

name                 old time/op    new time/op    delta
FloatSqrt/64-4          798ns ± 3%     802ns ± 3%     ~     (p=0.458 n=8+8)
FloatSqrt/128-4        1.65µs ± 1%    1.65µs ± 1%     ~     (p=0.290 n=8+8)
FloatSqrt/256-4        3.10µs ± 1%    2.10µs ± 0%  -32.32%  (p=0.000 n=8+7)
FloatSqrt/1000-4       8.83µs ± 1%    4.91µs ± 2%  -44.39%  (p=0.000 n=8+8)
FloatSqrt/10000-4       107µs ± 1%      40µs ± 1%  -62.68%  (p=0.000 n=8+8)
FloatSqrt/100000-4     2.91ms ± 1%    0.96ms ± 1%  -67.13%  (p=0.000 n=8+8)
FloatSqrt/1000000-4     240ms ± 1%      80ms ± 1%  -66.66%  (p=0.000 n=8+8)

name                 old alloc/op   new alloc/op   delta
FloatSqrt/64-4           416B ± 0%      416B ± 0%     ~     (all equal)
FloatSqrt/128-4          720B ± 0%      720B ± 0%     ~     (all equal)
FloatSqrt/256-4        1.34kB ± 0%    0.82kB ± 0%  -39.29%  (p=0.000 n=8+8)
FloatSqrt/1000-4       5.09kB ± 0%    2.50kB ± 0%  -50.94%  (p=0.000 n=8+8)
FloatSqrt/10000-4      45.9kB ± 0%    23.5kB ± 0%  -48.81%  (p=0.000 n=8+8)
FloatSqrt/100000-4      533kB ± 0%     251kB ± 0%  -52.90%  (p=0.000 n=8+8)
FloatSqrt/1000000-4    9.21MB ± 0%    4.61MB ± 0%  -49.98%  (p=0.000 n=8+8)

name                 old allocs/op  new allocs/op  delta
FloatSqrt/64-4           9.00 ± 0%      9.00 ± 0%     ~     (all equal)
FloatSqrt/128-4          13.0 ± 0%      13.0 ± 0%     ~     (all equal)
FloatSqrt/256-4          15.0 ± 0%      12.0 ± 0%  -20.00%  (p=0.000 n=8+8)
FloatSqrt/1000-4         24.0 ± 0%      19.0 ± 0%  -20.83%  (p=0.000 n=8+8)
FloatSqrt/10000-4        40.0 ± 0%      35.0 ± 0%  -12.50%  (p=0.000 n=8+8)
FloatSqrt/100000-4       66.0 ± 0%      55.0 ± 0%  -16.67%  (p=0.000 n=8+8)
FloatSqrt/1000000-4       143 ± 0%       122 ± 0%  -14.69%  (p=0.000 n=8+8)

Change-Id: I4868adb7f8960f2ca20e7792734c2e6211669fc0
Reviewed-on: https://go-review.googlesource.com/75010
Reviewed-by: Robert Griesemer <gri@golang.org>
2017-11-01 16:21:06 +00:00
Alberto Donizetti 2c783dc038 math/big: save one subtraction per iteration in Float.Sqrt
The Sqrt Newton method computes g(t) = f(t)/f'(t) and then iterates

  t2 = t1 - g(t1)

We can save one operation by including the final subtraction in g(t)
and evaluating the resulting expression symbolically.

For example, for the direct method,

  g(t) = ½(t² - x)/t

and we use 2 multiplications, 1 division and 1 subtraction in g(),
plus 1 final subtraction; but if we compute

  t - g(t) = t - ½(t² - x)/t = ½(t² + x)/t

we only use 2 multiplications, 1 division and 1 addition.

A similar simplification can be done for the inverse method.

name                 old time/op    new time/op    delta
FloatSqrt/64-4          889ns ± 4%     790ns ± 1%  -11.19%  (p=0.000 n=8+7)
FloatSqrt/128-4        1.82µs ± 0%    1.64µs ± 1%  -10.07%  (p=0.001 n=6+8)
FloatSqrt/256-4        3.56µs ± 4%    3.10µs ± 3%  -12.96%  (p=0.000 n=7+8)
FloatSqrt/1000-4       9.06µs ± 3%    8.86µs ± 1%   -2.20%  (p=0.001 n=7+7)
FloatSqrt/10000-4       109µs ± 1%     107µs ± 1%   -1.56%  (p=0.000 n=8+8)
FloatSqrt/100000-4     2.91ms ± 0%    2.89ms ± 2%   -0.68%  (p=0.026 n=7+7)
FloatSqrt/1000000-4     237ms ± 1%     239ms ± 1%   +0.72%  (p=0.021 n=8+8)

name                 old alloc/op   new alloc/op   delta
FloatSqrt/64-4           448B ± 0%      416B ± 0%   -7.14%  (p=0.000 n=8+8)
FloatSqrt/128-4          752B ± 0%      720B ± 0%   -4.26%  (p=0.000 n=8+8)
FloatSqrt/256-4        2.05kB ± 0%    1.34kB ± 0%  -34.38%  (p=0.000 n=8+8)
FloatSqrt/1000-4       6.91kB ± 0%    5.09kB ± 0%  -26.39%  (p=0.000 n=8+8)
FloatSqrt/10000-4      60.5kB ± 0%    45.9kB ± 0%  -24.17%  (p=0.000 n=8+8)
FloatSqrt/100000-4      617kB ± 0%     533kB ± 0%  -13.57%  (p=0.000 n=8+8)
FloatSqrt/1000000-4    10.3MB ± 0%     9.2MB ± 0%  -10.85%  (p=0.000 n=8+8)

name                 old allocs/op  new allocs/op  delta
FloatSqrt/64-4           9.00 ± 0%      9.00 ± 0%     ~     (all equal)
FloatSqrt/128-4          13.0 ± 0%      13.0 ± 0%     ~     (all equal)
FloatSqrt/256-4          20.0 ± 0%      15.0 ± 0%  -25.00%  (p=0.000 n=8+8)
FloatSqrt/1000-4         31.0 ± 0%      24.0 ± 0%  -22.58%  (p=0.000 n=8+8)
FloatSqrt/10000-4        50.0 ± 0%      40.0 ± 0%  -20.00%  (p=0.000 n=8+8)
FloatSqrt/100000-4       76.0 ± 0%      66.0 ± 0%  -13.16%  (p=0.000 n=8+8)
FloatSqrt/1000000-4       146 ± 0%       143 ± 0%   -2.05%  (p=0.000 n=8+8)

Change-Id: I271c00de1ca9740e585bf2af7bcd87b18c1fa68e
Reviewed-on: https://go-review.googlesource.com/73879
Run-TryBot: Alberto Donizetti <alb.donizetti@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
2017-11-01 11:24:02 +00:00
Ilya Tocar 94484d8ed5 cmd/compile: intrinsify math.{Trunc/Ceil/Floor} on amd64
This significantly speed-ups Trunc.
Ceil/Floor are using the same instruction, so do them too.

name     old time/op  new time/op  delta
Floor-6  3.33ns ± 1%  3.22ns ± 0%   -3.39%  (p=0.000 n=10+10)
Ceil-6   3.33ns ± 1%  3.22ns ± 0%   -3.16%  (p=0.000 n=10+7)
Trunc-6  4.83ns ± 0%  3.22ns ± 0%  -33.36%  (p=0.000 n=6+8)

Change-Id: If848790e458eedfe38a6a0407bb4f589c68ac254
Reviewed-on: https://go-review.googlesource.com/68630
Run-TryBot: Ilya Tocar <ilya.tocar@intel.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
2017-10-31 19:30:54 +00:00
Michael Munday c280126557 cmd/asm, cmd/internal/obj/s390x, math: add "test under mask" instructions
Adds the following s390x test under mask (immediate) instructions:

TMHH
TMHL
TMLH
TMLL

These are useful for testing bits and are already used in the math package.

Change-Id: Idffb3f83b238dba76ac1e42ac6b0bf7f1d11bea2
Reviewed-on: https://go-review.googlesource.com/41092
Run-TryBot: Michael Munday <mike.munday@ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2017-10-30 23:55:14 +00:00
Michael Munday b97688d112 math: optimize dim and remove s390x assembly implementation
By calculating dim directly, rather than calling max, we can simplify
the generated code significantly. The compiler now reports that dim
is easily inlineable, but it can't be inlined because there is still
an assembly stub for Dim.

Since dim is now very simple I no longer think it is worth having
assembly implementations of it. I have therefore removed the s390x
assembly. Removing the other assembly for Dim is #21913.

name  old time/op  new time/op  delta
Dim   4.29ns ± 0%  3.53ns ± 0%  -17.62%  (p=0.000 n=9+8)

Change-Id: Ic38a6b51603cbc661dcdb868ecf2b1947e9f399e
Reviewed-on: https://go-review.googlesource.com/64194
Run-TryBot: Michael Munday <mike.munday@ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
2017-10-30 19:05:51 +00:00
Alberto Donizetti bd48d37e30 math/big: add (*Float).Sqrt
This change adds a Square root method to the big.Float type, with
signature

  (z *Float) Sqrt(x *Float) *Float

Fixes #20460

Change-Id: I050aaed0615fe0894e11c800744600648343c223
Reviewed-on: https://go-review.googlesource.com/67830
Run-TryBot: Alberto Donizetti <alb.donizetti@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
2017-10-26 17:29:27 +00:00
Brian Kessler 1643d4f33a math/big: implement Lehmer's GCD algorithm
Updates #15833

Lehmer's GCD algorithm uses single precision calculations
to simulate several steps of multiple precision calculations
in Euclid's GCD algorithm which leads to a considerable
speed up.  This implementation uses Collins' simplified
testing condition on the single digit cosequences which
requires only one quotient and avoids any possibility of
overflow.

name                          old time/op  new time/op  delta
GCD10x10/WithoutXY-4          1.82µs ±24%  0.28µs ± 6%  -84.40%  (p=0.008 n=5+5)
GCD10x10/WithXY-4             1.69µs ± 6%  1.71µs ± 6%     ~     (p=0.595 n=5+5)
GCD10x100/WithoutXY-4         1.87µs ± 2%  0.56µs ± 4%  -70.13%  (p=0.008 n=5+5)
GCD10x100/WithXY-4            2.61µs ± 2%  2.65µs ± 4%     ~     (p=0.635 n=5+5)
GCD10x1000/WithoutXY-4        2.75µs ± 2%  1.48µs ± 1%  -46.06%  (p=0.008 n=5+5)
GCD10x1000/WithXY-4           5.29µs ± 2%  5.25µs ± 2%     ~     (p=0.548 n=5+5)
GCD10x10000/WithoutXY-4       10.7µs ± 2%  10.3µs ± 0%   -4.38%  (p=0.008 n=5+5)
GCD10x10000/WithXY-4          22.3µs ± 6%  22.1µs ± 1%     ~     (p=1.000 n=5+5)
GCD10x100000/WithoutXY-4      93.7µs ± 2%  99.4µs ± 2%   +6.09%  (p=0.008 n=5+5)
GCD10x100000/WithXY-4          196µs ± 2%   199µs ± 2%     ~     (p=0.222 n=5+5)
GCD100x100/WithoutXY-4        10.1µs ± 2%   2.5µs ± 2%  -74.84%  (p=0.008 n=5+5)
GCD100x100/WithXY-4           21.4µs ± 2%  21.3µs ± 7%     ~     (p=0.548 n=5+5)
GCD100x1000/WithoutXY-4       11.3µs ± 2%   4.4µs ± 4%  -60.87%  (p=0.008 n=5+5)
GCD100x1000/WithXY-4          24.7µs ± 3%  23.9µs ± 1%     ~     (p=0.056 n=5+5)
GCD100x10000/WithoutXY-4      26.6µs ± 1%  20.0µs ± 2%  -24.82%  (p=0.008 n=5+5)
GCD100x10000/WithXY-4         78.7µs ± 2%  78.2µs ± 2%     ~     (p=0.690 n=5+5)
GCD100x100000/WithoutXY-4      174µs ± 2%   171µs ± 1%     ~     (p=0.056 n=5+5)
GCD100x100000/WithXY-4         563µs ± 4%   561µs ± 2%     ~     (p=1.000 n=5+5)
GCD1000x1000/WithoutXY-4       120µs ± 5%    29µs ± 3%  -75.71%  (p=0.008 n=5+5)
GCD1000x1000/WithXY-4          355µs ± 4%   358µs ± 2%     ~     (p=0.841 n=5+5)
GCD1000x10000/WithoutXY-4      140µs ± 2%    49µs ± 2%  -65.07%  (p=0.008 n=5+5)
GCD1000x10000/WithXY-4         626µs ± 3%   628µs ± 9%     ~     (p=0.690 n=5+5)
GCD1000x100000/WithoutXY-4     340µs ± 4%   259µs ± 6%  -23.79%  (p=0.008 n=5+5)
GCD1000x100000/WithXY-4       3.76ms ± 4%  3.82ms ± 5%     ~     (p=0.310 n=5+5)
GCD10000x10000/WithoutXY-4    3.11ms ± 3%  0.54ms ± 2%  -82.74%  (p=0.008 n=5+5)
GCD10000x10000/WithXY-4       7.96ms ± 3%  7.69ms ± 3%     ~     (p=0.151 n=5+5)
GCD10000x100000/WithoutXY-4   3.88ms ± 1%  1.27ms ± 2%  -67.21%  (p=0.008 n=5+5)
GCD10000x100000/WithXY-4      38.1ms ± 2%  38.8ms ± 1%     ~     (p=0.095 n=5+5)
GCD100000x100000/WithoutXY-4   208ms ± 1%    25ms ± 4%  -88.07%  (p=0.008 n=5+5)
GCD100000x100000/WithXY-4      533ms ± 5%   525ms ± 4%     ~     (p=0.548 n=5+5)

Change-Id: Ic1e007eb807b93e75f4752e968e98c1f0cb90e43
Reviewed-on: https://go-review.googlesource.com/59450
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
2017-10-24 22:42:43 +00:00
Mark Pulford a5c44f3e3f math: add RoundToEven function
Rounding ties to even is statistically useful for some applications.
This implementation completes IEEE float64 rounding mode support (in
addition to Round, Ceil, Floor, Trunc).

This function avoids subtle faults found in ad-hoc implementations, and
is simple enough to be inlined by the compiler.

Fixes #21748

Change-Id: I09415df2e42435f9e7dabe3bdc0148e9b9ebd609
Reviewed-on: https://go-review.googlesource.com/61211
Reviewed-by: Robert Griesemer <gri@golang.org>
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-10-24 22:33:09 +00:00
Matthew Dempsky a5868a47c6 cmd/internal/obj/x86: move MOV->XOR rewriting into compiler
Fixes #20986.

Change-Id: Ic3cf5c0ab260f259ecff7b92cfdf5f4ae432aef3
Reviewed-on: https://go-review.googlesource.com/73072
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
2017-10-24 21:32:17 +00:00
Filippo Valsorda f75158c365 math/big: fix ModSqrt optimized path for x = z
name                   old time/op  new time/op  delta
ModSqrt224_3Mod4-4      153µs ± 2%   154µs ± 1%   ~     (p=0.548 n=5+5)
ModSqrt5430_3Mod4-4     776ms ± 2%   791ms ± 2%   ~     (p=0.222 n=5+5)

Fixes #22265

Change-Id: If233542716e04341990a45a1c2b7118da6d233f7
Reviewed-on: https://go-review.googlesource.com/70832
Run-TryBot: Filippo Valsorda <hi@filippo.io>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
2017-10-16 21:41:44 +00:00
griesemer 51cfe6849a math/big: provide support for conversion bases up to 62
Increase MaxBase from 36 to 62 and extend the conversion
alphabet with the upper-case letters 'A' to 'Z'. For int
conversions with bases <= 36, the letters 'A' to 'Z' have
the same values (10 to 35) as the corresponding lower-case
letters. For conversion bases > 36 up to 62, the upper-case
letters have the values 36 to 61.

Added MaxBase to api/except.txt: Clients should not make
assumptions about the value of MaxBase being constant.

The core of the change is in natconv.go. The remaining
changes are adjusted tests and documentation.

Fixes #21558.

Change-Id: I5f74da633caafca03993e13f32ac9546c572cc84
Reviewed-on: https://go-review.googlesource.com/65970
Reviewed-by: Martin Möhrmann <moehrmann@google.com>
2017-10-06 17:46:15 +00:00
griesemer 2ddd07138d math/bits: complete examples
Change-Id: Icbe6885ffd3aa4e77441ab03a2b9a04a9276d5eb
Reviewed-on: https://go-review.googlesource.com/68311
Reviewed-by: Martin Möhrmann <moehrmann@google.com>
2017-10-06 16:58:03 +00:00
Marvin Stenger 90d71fe99e all: revert "all: prefer strings.IndexByte over strings.Index"
This reverts https://golang.org/cl/65930.

Fixes #22148

Change-Id: Ie0712621ed89c43bef94417fc32de9af77607760
Reviewed-on: https://go-review.googlesource.com/68430
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-10-05 23:19:10 +00:00
Marvin Stenger aa00c607e1 math/big: remove []byte/string conversions
This removes some of the []byte/string conversions currently
existing in the (un)marshaling methods of Int and Rat.

For Int we introduce a new function (*Int).setFromScanner() essentially
implementing the SetString method being given an io.ByteScanner instead
of a string. So we can handle the string case in (*Int).SetString with
a *strings.Reader and the []byte case in (*Int).UnmarshalText() with a
*bytes.Reader now avoiding the []byte/string conversion here.

For Rat we introduce a new function (*Rat).marshal() essentially
implementing the String method outputting []byte instead of string.
Using this new function and the same formatting rules as in
(*Rat).RatString we can implement (*Rat).MarshalText() without
the []byte/string conversion it used to have.

Change-Id: Ic5ef246c1582c428a40f214b95a16671ef0a06d9
Reviewed-on: https://go-review.googlesource.com/65950
Reviewed-by: Robert Griesemer <gri@golang.org>
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-10-04 17:16:52 +00:00
Marvin Stenger f22ba1f247 all: prefer strings.IndexByte over strings.Index
strings.IndexByte was introduced in go1.2 and it can be used
effectively wherever the second argument to strings.Index is
exactly one byte long.

This avoids generating unnecessary string symbols and saves
a few calls to strings.Index.

Change-Id: I1ab5edb7c4ee9058084cfa57cbcc267c2597e793
Reviewed-on: https://go-review.googlesource.com/65930
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-09-25 17:35:41 +00:00
Marvin Stenger 7a5d76fa62 math/big: delete solved TODO
The TODO is no longer needed as it was solved by a previous CL.
See https://go-review.googlesource.com/14995.

Change-Id: If62d1b296f35758ad3d18d28c8fbb95e797f4464
Reviewed-on: https://go-review.googlesource.com/65232
Reviewed-by: Robert Griesemer <gri@golang.org>
2017-09-22 10:21:46 +00:00
Agniva De Sarker d2f317218b math: implement fast path for Exp
- using FMA and AVX instructions if available to speed-up
Exp calculation on amd64

- using a data table instead of #define'ed constants because
these instructions do not support loading floating point immediates.
One has to use a memory operand / register.

- Benchmark results on Intel(R) Core(TM) i5-5200U CPU @ 2.20GHz:

Original vs New (non-FMA path)
name  old time/op    new time/op    delta
Exp     16.0ns ± 1%    16.1ns ± 3%   ~     (p=0.308 n=9+10)

Original vs New (FMA path)
name  old time/op    new time/op    delta
Exp     16.0ns ± 1%    13.7ns ± 2%  -14.80%  (p=0.000 n=9+10)

Change-Id: I3d8986925d82b39b95ee979ae06f59d7e591d02e
Reviewed-on: https://go-review.googlesource.com/62590
Reviewed-by: Ilya Tocar <ilya.tocar@intel.com>
Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-09-20 21:43:00 +00:00
Burak Guven 9cc170f9a5 math/rand: fix comment for Shuffle
Shuffle panics if n < 0, not n <= 0. The comment for the (*Rand).Shuffle
function is already accurate.

Change-Id: I073049310bca9632e50e9ca3ff79eec402122793
Reviewed-on: https://go-review.googlesource.com/63750
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-09-14 03:41:35 +00:00
Michael Munday ffb4708d1b math: fix Abs, Copysign and Signbit benchmarks
CL 62250 makes constant folding a bit more aggressive and these
benchmarks were optimized away. This CL adds some indirection to
the function arguments to stop them being folded.

The Copysign benchmark is a bit faster because I've left one
argument as a constant and it can be partially folded.

                     old           CL 62250     this CL
Copysign             1.24ns ± 0%   0.34ns ± 2%  1.02ns ± 2%
Abs                  0.67ns ± 0%   0.35ns ± 3%  0.67ns ± 0%
Signbit              0.87ns ± 0%   0.35ns ± 2%  0.87ns ± 1%

Change-Id: I9604465a87d7aa29f4bd6009839c8ee354be3cd7
Reviewed-on: https://go-review.googlesource.com/62450
Run-TryBot: Michael Munday <mike.munday@ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-09-09 16:52:16 +00:00
Ian Lance Taylor 44f7fd030f math/rand: change http to https in comment
Change-Id: I19c1b0e1b238dda82e69bd47459528ed06b55840
Reviewed-on: https://go-review.googlesource.com/62310
Reviewed-by: David Crawshaw <crawshaw@golang.org>
2017-09-08 22:11:55 +00:00
Josh Bleecher Snyder caae0917bf math/rand: make Perm match Shuffle
Perm and Shuffle are fundamentally doing the same work.
This change makes Perm's algorithm match Shuffle's.
In addition to allowing developers to switch more
easily between the two methods, it affords a nice speed-up:

name      old time/op  new time/op  delta
Perm3-8   75.7ns ± 1%  51.8ns ± 1%  -31.59%  (p=0.000 n=9+8)
Perm30-8   610ns ± 1%   405ns ± 1%  -33.67%  (p=0.000 n=9+9)

This change alters the output from Perm,
given the same Source and seed.
This is a change from Go 1.0 behavior.
This necessitates updating the regression test.

This also changes the number of calls made to the Source
during Perm, which changes the output of the math/rand examples.

This also slightly perturbs the output of Perm,
nudging it out of the range currently accepted by TestUniformFactorial.
However, it is complete unclear that the helpers relied on
by TestUniformFactorial are correct. That is #21211.
This change updates checkSimilarDistribution to respect
closeEnough for standard deviations, which makes the test pass.
The whole situation is muddy; see #21211 for details.

There is an alternative implementation of Perm
that avoids initializing m, which is more similar
to the existing implementation, plus some optimizations:

func (r *Rand) Perm(n int) []int {
	m := make([]int, n)
	max31 := n
	if n > 1<<31-1-1 {
		max31 = 1<<31 - 1 - 1
	}
	i := 1
	for ; i < max31; i++ {
		j := r.int31n(int32(i + 1))
		m[i] = m[j]
		m[j] = i
	}
	for ; i < n; i++ {
		j := r.Int63n(int64(i + 1))
		m[i] = m[j]
		m[j] = i
	}
	return m
}

This is a tiny bit faster than the implementation
actually used in this change:

name      old time/op  new time/op  delta
Perm3-8   51.8ns ± 1%  50.3ns ± 1%  -2.83%  (p=0.000 n=8+9)
Perm30-8   405ns ± 1%   394ns ± 1%  -2.66%  (p=0.000 n=9+8)

However, 3% in performance doesn't seem worth
having the two algorithms diverge,
nor the reduced readability of this alternative.

Updates #16213.

Change-Id: I11a7441ff8837ee9c241b4c88f7aa905348be781
Reviewed-on: https://go-review.googlesource.com/55972
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
2017-09-08 13:26:20 +00:00
Josh Bleecher Snyder a2dfe5d278 math/rand: add Shuffle
Shuffle uses the Fisher-Yates algorithm.

Since this is new API, it affords us the opportunity
to use a much faster Int31n implementation that mostly avoids division.
As a result, BenchmarkPerm30ViaShuffle is
about 30% faster than BenchmarkPerm30,
despite requiring a separate initialization loop
and using function calls to swap elements.

Fixes #20480
Updates #16213
Updates #21211

Change-Id: Ib8956c4bebed9d84f193eb98282ec16ee7c2b2d5
Reviewed-on: https://go-review.googlesource.com/51891
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-09-08 13:03:02 +00:00
Mark Pulford 03c3bb5f84 math: Add Round function (ties away from zero)
This function avoids subtle faults found in many ad-hoc implementations,
and is simple enough to be inlined by the compiler.

Fixes #20100

Change-Id: Ib320254e9b1f1f798c6ef906b116f63bc29e8d08
Reviewed-on: https://go-review.googlesource.com/43652
Reviewed-by: Robert Griesemer <gri@golang.org>
2017-09-02 21:00:08 +00:00
griesemer f7cb5bca1a math/big: fix internal comment
Change-Id: Id003e2dbecad7b3c249a747f8b4032135dfbe34f
Reviewed-on: https://go-review.googlesource.com/60670
Reviewed-by: Marcel van Lohuizen <mpvl@golang.org>
2017-08-31 13:05:11 +00:00
jaredculp dc42ffff59 math: add examples for trig functions
Change-Id: Ic3ce2f3c055f2636ec8fc9cec8592e596b18dc05
Reviewed-on: https://go-review.googlesource.com/54771
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-08-25 20:26:19 +00:00
Keith Randall fb05948d9e cmd/compile,math: improve code generation for math.Abs
Implement int reg <-> fp reg moves on amd64.
If we see a load to int reg followed by an int->fp move, then we can just
load to the fp reg instead.  Same for stores.

math.Abs is now:

MOVQ	"".x+8(SP), AX
SHLQ	$1, AX
SHRQ	$1, AX
MOVQ	AX, "".~r1+16(SP)

math.Copysign is now:

MOVQ	"".x+8(SP), AX
SHLQ	$1, AX
SHRQ	$1, AX
MOVQ	"".y+16(SP), CX
SHRQ	$63, CX
SHLQ	$63, CX
ORQ	CX, AX
MOVQ	AX, "".~r2+24(SP)

math.Float64bits is now:

MOVSD	"".x+8(SP), X0
MOVSD	X0, "".~r1+16(SP)
(it would be nicer to use a non-SSE reg for this, nothing is perfect)

And due to the fix for #21440, the inlined version of these improve as well.

name      old time/op  new time/op  delta
Abs       1.38ns ± 5%  0.89ns ±10%  -35.54%  (p=0.000 n=10+10)
Copysign  1.56ns ± 7%  1.35ns ± 6%  -13.77%  (p=0.000 n=9+10)

Fixes #13095

Change-Id: Ibd7f2792412a6668608780b0688a77062e1f1499
Reviewed-on: https://go-review.googlesource.com/58732
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Ilya Tocar <ilya.tocar@intel.com>
2017-08-25 19:15:01 +00:00
Agniva De Sarker ea5e3bd2a1 all: fix easy-to-miss typos
Using the wonderful https://github.com/client9/misspell tool.

Change-Id: Icdbc75a5559854f4a7a61b5271bcc7e3f99a1a24
Reviewed-on: https://go-review.googlesource.com/57851
Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>
Run-TryBot: Joe Tsai <thebrokentoaster@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-08-23 03:07:12 +00:00
Lakshay Garg 4c0bba158e math: implement the erfcinv function
Fixes: #6359

Change-Id: I6c697befd681a253e73a7091faa9f20ff3791201
Reviewed-on: https://go-review.googlesource.com/57090
Reviewed-by: Robert Griesemer <gri@golang.org>
2017-08-22 13:13:20 +00:00
Brian Kessler edaa0ffadb math/big: use internal sqr on nats
Replace z.mul(x, x) calls on nats in internal code with z.sqr(x)
that employs optimized squaring routines. Benchmark results:

Exp-4                             12.9ms ± 2%  12.8ms ± 3%     ~     (p=0.165 n=10+10)
Exp2-4                            13.0ms ± 4%  12.8ms ± 2%   -2.14%  (p=0.015 n=8+9)
ModSqrt225_Tonelli-4               987µs ± 4%   989µs ± 2%     ~     (p=0.673 n=8+9)
ModSqrt224_3Mod4-4                 300µs ± 2%   301µs ± 3%     ~     (p=0.546 n=9+9)
ModSqrt5430_Tonelli-4              4.88s ± 6%   4.82s ± 5%     ~     (p=0.247 n=10+10)
ModSqrt5430_3Mod4-4                1.62s ±10%   1.57s ± 1%     ~     (p=0.094 n=9+9)
Exp3Power/0x10-4                   496ns ± 7%   426ns ± 7%  -14.21%  (p=0.000 n=10+10)
Exp3Power/0x40-4                   575ns ± 5%   470ns ± 7%  -18.20%  (p=0.000 n=9+10)
Exp3Power/0x100-4                  929ns ±19%   770ns ±10%  -17.13%  (p=0.000 n=10+10)
Exp3Power/0x400-4                 1.96µs ± 7%  1.79µs ± 5%   -8.68%  (p=0.000 n=10+10)
Exp3Power/0x1000-4                10.9µs ± 9%   7.9µs ± 5%  -28.02%  (p=0.000 n=10+10)
Exp3Power/0x4000-4                86.8µs ± 8%  67.3µs ± 8%  -22.41%  (p=0.000 n=10+10)
Exp3Power/0x10000-4                750µs ± 8%   731µs ± 1%     ~     (p=0.074 n=9+8)
Exp3Power/0x40000-4               7.07ms ± 7%  7.05ms ± 4%     ~     (p=0.931 n=9+9)
Exp3Power/0x100000-4              64.7ms ± 2%  65.6ms ± 6%     ~     (p=0.661 n=9+10)
Exp3Power/0x400000-4               577ms ± 2%   580ms ± 3%     ~     (p=0.931 n=9+9)
ProbablyPrime/n=0-4               9.08ms ±17%  9.09ms ±16%     ~     (p=0.447 n=9+10)
ProbablyPrime/n=1-4               10.8ms ± 4%  10.7ms ± 2%     ~     (p=0.243 n=10+9)
ProbablyPrime/n=5-4               18.5ms ± 3%  18.5ms ± 1%     ~     (p=0.863 n=9+9)
ProbablyPrime/n=10-4              28.6ms ± 6%  28.2ms ± 1%     ~     (p=0.050 n=9+9)
ProbablyPrime/n=20-4              48.4ms ± 4%  48.4ms ± 2%     ~     (p=0.739 n=10+10)
ProbablyPrime/Lucas-4             6.75ms ± 4%  6.75ms ± 2%     ~     (p=0.963 n=9+8)
ProbablyPrime/MillerRabinBase2-4  2.00ms ± 5%  2.00ms ± 7%     ~     (p=0.931 n=9+9)

Change-Id: Ibe9f58d11dbad25eb369faedf480b666a0250a6b
Reviewed-on: https://go-review.googlesource.com/56773
Reviewed-by: Robert Griesemer <gri@golang.org>
2017-08-22 08:04:44 +00:00
Lakshay Garg 77412b9300 math: implement the erfinv function
This commit defines the inverse of error function (erfinv) in the
math package. The function is based on the rational approximation
of percentage points of normal distribution available at
https://www.jstor.org/stable/pdf/2347330.pdf.

Fixes #6359

Change-Id: Icfe4508f623e0574c7fffdbf7aa929540fd4c944
Reviewed-on: https://go-review.googlesource.com/46990
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
2017-08-18 13:30:46 +00:00
Brian Kessler 497f891fce math/big: recognize squaring for Floats
Updates #13745

Recognize z.Mul(x, x) as squaring for Floats and use
the internal z.sqr(x) method for nat on the mantissa.

Change-Id: I0f792157bad93a13cae1aecc4c10bd20c6397693
Reviewed-on: https://go-review.googlesource.com/56774
Reviewed-by: Robert Griesemer <gri@golang.org>
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-08-18 12:48:10 +00:00
Brian Kessler fe08ebaebb math/big: use internal square for Rat
updates #13745

A squared rational is always positive and can not
be reduced since the numerator and denominator had
no previous common factors.  The nat multiplication
can be performed using the internal sqr method.

Change-Id: I558f5b38e379bfd26ff163c9489006d7e5a9cfaa
Reviewed-on: https://go-review.googlesource.com/56776
Reviewed-by: Robert Griesemer <gri@golang.org>
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-08-18 12:47:46 +00:00
Daniel Martí 59413d34c9 all: unindent some big chunks of code
Found with mvdan.cc/unindent. Prioritized the ones with the biggest wins
for now.

Change-Id: I2b032e45cdd559fc9ed5b1ee4c4de42c4c92e07b
Reviewed-on: https://go-review.googlesource.com/56470
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-08-18 06:59:48 +00:00
crvv d46953c9f6 math: fix inaccurate result of Exp(1)
The existing implementation is translated from C, which uses a
polynomial coefficient very close to 1/6. If the function uses
1/6 as this coeffient, the result of Exp(1) will be more accurate.
And this change doesn't introduce more error to Exp function.

Fixes #20319

Change-Id: I94c236a18cf95570ebb69f7fb99884b0d7cf5f6e
Reviewed-on: https://go-review.googlesource.com/49294
Reviewed-by: Robert Griesemer <gri@golang.org>
2017-08-17 09:01:27 +00:00
Brian Kessler 25b040c287 math/big: recognize z.Mul(x, x) as squaring of x
updates #13745

Multiprecision squaring can be done in a straightforward manner
with about half the multiplications of a basic multiplication
due to the symmetry of the operands.  This change implements
basic squaring for nat types and uses it for Int multiplication
when the same variable is supplied to both arguments of
z.Mul(x, x). This has some overhead to allocate a temporary
variable to hold the cross products, shift them to double and
add them to the diagonal terms.  There is a speed benefit in
the intermediate range when the overhead is neglible and the
asymptotic performance of karatsuba multiplication has not been
reached.

basicSqrThreshold = 20
karatsubaSqrThreshold = 400

Were set by running calibrate_test.go to measure timing differences
between the algorithms.  Benchmarks for squaring:

name           old time/op  new time/op  delta
IntSqr/1-4     51.5ns ±25%  25.1ns ± 7%  -51.38%  (p=0.008 n=5+5)
IntSqr/2-4     79.1ns ± 4%  72.4ns ± 2%   -8.47%  (p=0.008 n=5+5)
IntSqr/3-4      102ns ± 4%    97ns ± 5%     ~     (p=0.056 n=5+5)
IntSqr/5-4      161ns ± 4%   163ns ± 7%     ~     (p=0.952 n=5+5)
IntSqr/8-4      277ns ± 5%   267ns ± 6%     ~     (p=0.087 n=5+5)
IntSqr/10-4     358ns ± 3%   360ns ± 4%     ~     (p=0.730 n=5+5)
IntSqr/20-4    1.07µs ± 3%  1.01µs ± 6%     ~     (p=0.056 n=5+5)
IntSqr/30-4    2.36µs ± 4%  1.72µs ± 2%  -27.03%  (p=0.008 n=5+5)
IntSqr/50-4    5.19µs ± 3%  3.88µs ± 4%  -25.37%  (p=0.008 n=5+5)
IntSqr/80-4    11.3µs ± 4%   8.6µs ± 3%  -23.78%  (p=0.008 n=5+5)
IntSqr/100-4   16.2µs ± 4%  12.8µs ± 3%  -21.49%  (p=0.008 n=5+5)
IntSqr/200-4   50.1µs ± 5%  44.7µs ± 3%  -10.65%  (p=0.008 n=5+5)
IntSqr/300-4    105µs ±11%    95µs ± 3%   -9.50%  (p=0.008 n=5+5)
IntSqr/500-4    231µs ± 5%   227µs ± 2%     ~     (p=0.310 n=5+5)
IntSqr/800-4    496µs ± 9%   459µs ± 3%   -7.40%  (p=0.016 n=5+5)
IntSqr/1000-4   700µs ± 3%   710µs ± 5%     ~     (p=0.841 n=5+5)

Show a speed up of 10-25% in the range where basicSqr is optimal,
improved single word squaring and no significant difference when
the fallback to standard multiplication is used.

Change-Id: Iae2c82ca91cf890823f91e5c83bbe9a2c534b72b
Reviewed-on: https://go-review.googlesource.com/53638
Reviewed-by: Robert Griesemer <gri@golang.org>
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-08-16 10:07:47 +00:00
Brian Kessler 53836a74f8 math/big: speed up GCD x, y calculation
The current implementation of the extended Euclidean GCD algorithm
calculates both cosequences x and y inside the division loop. This
is unneccessary since the second Bezout coefficient can be obtained
at the end of calculation via a multiplication, subtraction and a
division.  In case only one coefficient is needed, e.g. ModInverse
this calculation can be skipped entirely.  This is a standard
optimization, see e.g.

"Handbook of Elliptic and Hyperelliptic Curve Cryptography"
Cohen et al pp 191
Available at:
http://cs.ucsb.edu/~koc/ccs130h/2013/EllipticHyperelliptic-CohenFrey.pdf

Updates #15833

Change-Id: I1e0d2e63567cfed97fd955048fe6373d36f22757
Reviewed-on: https://go-review.googlesource.com/50530
Reviewed-by: Robert Griesemer <gri@golang.org>
2017-08-16 09:13:12 +00:00
Brian Kessler 1246566142 math: eliminate overflow in Pow(x,y) for large y
The current implementation uses a shift and add
loop to compute the product of x's exponent xe and
the integer part of y (yi) for yi up to 1<<63.
Since xe is an 11-bit exponent, this product can be
up to 74-bits and overflow both 32 and 64-bit int.

This change checks whether the accumulated exponent
will fit in the 11-bit float exponent of the output
and breaks out of the loop early if overflow is detected.

The current handling of yi >= 1<<63 uses Exp(y * Log(x))
which incorrectly returns Nan for x<0.  In addition,
for y this large, Exp(y * Log(x)) can be enumerated
to only overflow except when x == -1 since the
boundary cases computed exactly:

Pow(NextAfter(1.0, Inf(1)), 1<<63)  == 2.72332... * 10^889
Pow(NextAfter(1.0, Inf(-1)), 1<<63) == 1.91624... * 10^-445

exceed the range of float64. So, the call can be
replaced with a simple case statement analgous to
y == Inf that correctly handles x < 0 as well.

Fixes #7394

Change-Id: I6f50dc951f3693697f9669697599860604323102
Reviewed-on: https://go-review.googlesource.com/48290
Reviewed-by: Robert Griesemer <gri@golang.org>
2017-08-16 09:10:10 +00:00
Carlos Eduardo Seo 3cb41be817 math/big: improve performance for AddMulVVW and mulAddVWW for ppc64x
This change adds a better implementation in asm for AddMulVVW and
mulAddVWW for ppc64x, with speedups up to 1.54x.

benchmark                       old ns/op     new ns/op     delta
BenchmarkAddMulVVW/1-8          6.58          6.29          -4.41%
BenchmarkAddMulVVW/2-8          7.43          7.25          -2.42%
BenchmarkAddMulVVW/3-8          8.95          8.15          -8.94%
BenchmarkAddMulVVW/4-8          10.1          9.37          -7.23%
BenchmarkAddMulVVW/5-8          12.0          10.7          -10.83%
BenchmarkAddMulVVW/10-8         22.1          20.1          -9.05%
BenchmarkAddMulVVW/100-8        211           154           -27.01%
BenchmarkAddMulVVW/1000-8       2046          1450          -29.13%
BenchmarkAddMulVVW/10000-8      20407         14793         -27.51%
BenchmarkAddMulVVW/100000-8     223857        145548        -34.98%

benchmark                       old MB/s     new MB/s     speedup
BenchmarkAddMulVVW/1-8          9719.88      10175.79     1.05x
BenchmarkAddMulVVW/2-8          17233.97     17657.54     1.02x
BenchmarkAddMulVVW/3-8          21446.05     23550.49     1.10x
BenchmarkAddMulVVW/4-8          25375.70     27334.33     1.08x
BenchmarkAddMulVVW/5-8          26650.52     30029.34     1.13x
BenchmarkAddMulVVW/10-8         28984.29     31833.68     1.10x
BenchmarkAddMulVVW/100-8        30249.41     41531.69     1.37x
BenchmarkAddMulVVW/1000-8       31273.35     44108.54     1.41x
BenchmarkAddMulVVW/10000-8      31360.47     43263.54     1.38x
BenchmarkAddMulVVW/100000-8     28589.58     43971.66     1.54x

Change-Id: I8a8105d4da3592afdef3125757a99f378a0254bb
Reviewed-on: https://go-review.googlesource.com/53931
Run-TryBot: Lynn Boger <laboger@linux.vnet.ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Lynn Boger <laboger@linux.vnet.ibm.com>
2017-08-11 13:59:52 +00:00
romanyx 92cfd07a6c math/bits: examples generator
Change-Id: Icdd0566d3b7dbc034256e16f8a6b6f1af07069b3
Reviewed-on: https://go-review.googlesource.com/54350
Reviewed-by: Robert Griesemer <gri@golang.org>
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-08-11 11:05:01 +00:00
Brian Kessler 9c7bf0807a math/big: avoid unneeded sticky bit calculations
As noted in the TODO comment, the sticky bit is only used
when the rounding bit is zero or the rounding mode is
ToNearestEven.  This change makes that check explicit and
will eliminate half the sticky bit calculations on average
when rounding mode is not ToNearestEven.

Change-Id: Ia4709f08f46e682bf97dabe5eb2a10e8e3d7af43
Reviewed-on: https://go-review.googlesource.com/54111
Reviewed-by: Robert Griesemer <gri@golang.org>
Run-TryBot: Robert Griesemer <gri@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
2017-08-11 09:52:30 +00:00
Wembley G. Leach, Jr 762a0bae06 math/bits: Add examples for Reverse functions
Change-Id: I30563d31f6acea594cc853cc6b672ec664f90d48
Reviewed-on: https://go-review.googlesource.com/53636
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Run-TryBot: Emmanuel Odeke <emm.odeke@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-08-09 18:02:36 +00:00
Than McIntosh ff560ee950 math: additional tests for Ldexp
Add test cases to verify behavior for Ldexp with exponents outside the
range of Minint32/Maxint32, for a gccgo bug.

Test for issue #21323.

Change-Id: Iea67bc6fcfafdfddf515cf7075bdac59360c277a
Reviewed-on: https://go-review.googlesource.com/54230
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-08-09 15:33:37 +00:00
romanyx fa155066c4 math/bits: some regular examples for functions
Change-Id: Iee1b3e116b4dcc4071d6512abc5241eabedaeb5c
Reviewed-on: https://go-review.googlesource.com/53850
Reviewed-by: Robert Griesemer <gri@golang.org>
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-08-09 13:25:29 +00:00
Josh Bleecher Snyder 6b53dd4f2b math/rand: use t.Helper in tests
Change-Id: Iece39e6412c0f6c63f563eed1621b8cca02de835
Reviewed-on: https://go-review.googlesource.com/51890
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Avelino <t@avelino.xxx>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-08-08 23:49:31 +00:00