It was removed in CL 217302 but was intentionally added in CL 217104.
Change-Id: I1a478d80ad1ec4f0a0184bfebf8f1a5e352cfe8c
Reviewed-on: https://go-review.googlesource.com/c/go/+/217941
Reviewed-by: Robert Griesemer <gri@golang.org>
We don't usually document past behavior (like "As of Go 1.14 ...") and
in isolation the current docs made it sound like a and b could only be
negative or zero.
Change-Id: I0d3c2b8579a9c01159ce528a3128b1478e99042a
Reviewed-on: https://go-review.googlesource.com/c/go/+/217302
Reviewed-by: Ian Lance Taylor <iant@golang.org>
The bounds in the last carry branch were wrong as there
is no reason for len(u) >= n+n/2 to always hold true.
We also adjust test to avoid using a remainder of 1
(in which case, the last step of the algorithm computes
(qhatv+1) - qhatv which rarely produces a carry).
Change-Id: I69fbab9c5e19d0db1c087fbfcd5b89352c2d26fb
Reviewed-on: https://go-review.googlesource.com/c/go/+/206839
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
There is a (theoretical, but possible) chance that the
random number values a, b used for TestDiv are 0 or 1,
in which case the test would fail.
This CL makes sure that a >= 1 and b >= 2 at all times.
Fixes#35523.
Change-Id: I6451feb94241249516a821cd0066e95a0c65b0ed
Reviewed-on: https://go-review.googlesource.com/c/go/+/206818
Run-TryBot: Robert Griesemer <gri@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
The current division algorithm produces one word of result at a time,
using 2-word division to compute the top word and mulAddVWW to compute
the remainder. The top word may need to be adjusted by 1 or 2 units.
The recursive version, based on Burnikel, Ziegler, "Fast Recursive Division",
uses the same principles, but in a multi-word setting, so that
multiplication benefits from the Karatsuba algorithm (and possibly later
improvements).
benchmark old ns/op new ns/op delta
BenchmarkDiv/20/10-4 38.2 38.3 +0.26%
BenchmarkDiv/40/20-4 38.7 38.5 -0.52%
BenchmarkDiv/100/50-4 62.5 62.6 +0.16%
BenchmarkDiv/200/100-4 238 259 +8.82%
BenchmarkDiv/400/200-4 311 338 +8.68%
BenchmarkDiv/1000/500-4 604 649 +7.45%
BenchmarkDiv/2000/1000-4 1214 1278 +5.27%
BenchmarkDiv/20000/10000-4 38279 36510 -4.62%
BenchmarkDiv/200000/100000-4 3022057 1359615 -55.01%
BenchmarkDiv/2000000/1000000-4 310827664 54012939 -82.62%
BenchmarkDiv/20000000/10000000-4 33272829421 1965401359 -94.09%
BenchmarkString/10/Base10-4 158 156 -1.27%
BenchmarkString/100/Base10-4 797 792 -0.63%
BenchmarkString/1000/Base10-4 3677 3814 +3.73%
BenchmarkString/10000/Base10-4 16633 17116 +2.90%
BenchmarkString/100000/Base10-4 5779029 1793808 -68.96%
BenchmarkString/1000000/Base10-4 889840820 85524031 -90.39%
BenchmarkString/10000000/Base10-4 134338236860 4935657026 -96.33%
Fixes#21960
Updates #30943
Change-Id: I134c6f81a47870c688ca95b6081eb9211def15a2
Reviewed-on: https://go-review.googlesource.com/c/go/+/172018
Reviewed-by: Robert Griesemer <gri@golang.org>
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This reverts CL 169501.
Reason for revert: The new tests fail at least on s390x and MIPS. This is likely a minor bug in the compiler or runtime. But this point in the release cycle is not the time to debug these details, which are unlikely to be new. Let's try again for 1.15.
Updates #29320Fixes#35443
Change-Id: I2218b2083f8974b57d528e3742524393fc72b355
Reviewed-on: https://go-review.googlesource.com/c/go/+/206037
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Implement special case handling and testing to ensure
conformance with the C99 standard annex G.6 Complex arithmetic.
Fixes#29320
Change-Id: Ieb0527191dd7fdea5b1aecb42b9e23aae3f74260
Reviewed-on: https://go-review.googlesource.com/c/go/+/169501
Run-TryBot: Brian Kessler <brian.m.kessler@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
This makes it a little less likely the portable FMA will be
broken without realizing it.
Change-Id: I7f7f4509b35160a9709f8b8a0e494c09ea6e410a
Reviewed-on: https://go-review.googlesource.com/c/go/+/205337
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
This API was added for #25819, where it was discussed as math.FMA.
The commit adding it used math.Fma, presumably for consistency
with the rest of the unusual names in package math
(Sincos, Acosh, Erfcinv, Float32bits, etc).
I believe that using an idiomatic Go name is more important here
than consistency with these other names, most of which are historical
baggage from C's standard library.
Early additions like Float32frombits happened before "uppercase for export"
(so they were originally like "float32frombits") and they were not properly
reconsidered when we uppercased the symbols to export them.
That's a mistake we live with.
The names of functions we have added since then, and even a few
that were legacy, are more properly Go-cased, such as IsNaN, IsInf,
and RoundToEven, rather than Isnan, Isinf, and Roundtoeven.
And also constants like MaxFloat32.
For new API, we should keep using proper Go-cased symbols
instead of minimally-upper-cased-C symbols.
So math.FMA, not math.Fma.
This API has not yet been released, so this change does not break
the compatibility promise.
This CL also modifies cmd/compile, since the compiler knows
the name of the function. I could have stopped at changing the
string constants, but it seemed to make more sense to use a
consistent casing everywhere.
Change-Id: I0f6f3407f41e99bfa8239467345c33945088896e
Reviewed-on: https://go-review.googlesource.com/c/go/+/205317
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Allow the inputs a and b to be zero or negative to GCD
with the following definitions.
If x or y are not nil, GCD sets their value such that z = a*x + b*y.
Regardless of the signs of a and b, z is always >= 0.
If a == b == 0, GCD sets z = x = y = 0.
If a == 0 and b != 0, GCD sets z = |b|, x = 0, y = sign(b) * 1.
If a != 0 and b == 0, GCD sets z = |a|, x = sign(a) * 1, y = 0.
Fixes#28878
Change-Id: Ia83fce66912a96545c95cd8df0549bfd852652f3
Reviewed-on: https://go-review.googlesource.com/c/go/+/164972
Run-TryBot: Brian Kessler <brian.m.kessler@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
A Rat is represented via a quotient a/b where a and b are Int values.
To make it possible to use an uninitialized Rat value (with a and b
uninitialized and thus == 0), the implementation treats a 0 denominator
as 1.
Rat.Num and Rat.Denom return pointers to these values a and b. Because
b may be 0, Rat.Denom used to first initialize it to 1 and thus produce
an undesirable side-effect (by changing the Rat's denominator).
This CL changes Denom to return a new (not shared) *Int with value 1
in the rare case where the Rat was not initialized. This eliminates
the side effect and returns the correct denominator value.
While this is changing behavior of the API, the impact should now be
minor because together with (prior) CL https://golang.org/cl/202997,
which initializes Rats ASAP, Denom is unlikely used to access the
denominator of an uninitialized (and thus 0) Rat. Any operation that
will somehow set a Rat value will ensure that the denominator is not 0.
Fixes#33792.
Updates #3521.
Change-Id: I0bf15ac60513cf52162bfb62440817ba36f0c3fc
Reviewed-on: https://go-review.googlesource.com/c/go/+/203059
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
A Rat is represented via a quotient a/b where a and b are Int values.
To make it possible to use an uninitialized Rat value (with a and b
uninitialized and thus == 0), the implementation treats a 0 denominator
as 1.
For each operation we check if the denominator is 0, and then treat
it as 1 (if necessary). Operations that create a new Rat result,
normalize that value such that a result denominator 1 is represened
as 0 again.
This CL changes this behavior slightly: 0 denominators are still
interpreted as 1, but whenever we (safely) can, we set an uninitialized
0 denominator to 1. This simplifies the code overall.
Also: Improved some doc strings.
Preparation for addressing issue #33792.
Updates #33792.
Change-Id: I3040587c8d0dad2e840022f96ca027d8470878a0
Reviewed-on: https://go-review.googlesource.com/c/go/+/202997
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Currently, the precision of the float64 multiply-add operation
(x * y) + z varies across architectures. While generated code for
ppc64, s390x, and arm64 can guarantee that there is no intermediate
rounding on those platforms, other architectures like x86, mips, and
arm will exhibit different behavior depending on available instruction
set. Consequently, applications cannot rely on results being identical
across GOARCH-dependent codepaths.
This CL introduces a software implementation that performs an IEEE 754
double-precision fused-multiply-add operation. The only supported
rounding mode is round-to-nearest ties-to-even. Separate CLs include
hardware implementations when available. Otherwise, this software
fallback is given as the default implementation.
Specifically,
- arm64, ppc64, s390x: Uses the FMA instruction provided by all
of these ISAs.
- mips[64][le]: Falls back to this software implementation. Only
release 6 of the ISA includes a strict FMA instruction with
MADDF.D (not implementation defined). Because the number of R6
processors in the wild is scarce, the assembly implementation
is left as a future optimization.
- x86: Guards the use of VFMADD213SD by checking cpu.X86.HasFMA.
- arm: Guards the use of VFMA by checking cpu.ARM.HasVFPv4.
- software fallback: Uses mostly integer arithmetic except
for input that involves Inf, NaN, or zero.
Updates #25819.
Change-Id: Iadadff2219638bacc9fec78d3ab885393fea4a08
Reviewed-on: https://go-review.googlesource.com/c/go/+/127458
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
The Div functions in math/bits (Div, Div32, and Div64) compute both
quotients and remainders, but they panic if the quotients do not not
fit a 32/64 uint.
Since, on the other hand, the remainder will always fit the size of
the divisor, it is useful to have Div variants that only compute the
remainder, and don't panic on a quotient overflow.
This change adds to the math/bits package three new functions:
Rem(hi, lo, y uint) uint
Rem32(hi, lo, y uint32) uint32
Rem64(hi, lo, y uint64) uint64
which can be used to compute (hi,lo)%y even when the quotient
overflows the uint size.
Fixes#28970
Change-Id: I119948429f737670c5e5ceb8756121e6a738dbdc
Reviewed-on: https://go-review.googlesource.com/c/go/+/197838
Run-TryBot: Alberto Donizetti <alb.donizetti@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Do not modify the underlying Rat denominator when calling
one of the accessors Float32, Float64; verify that we don't
modify the Rat denominator when calling Inv, Sign, IsInt, Num.
Fixes#34919.
Reopens#33792.
Change-Id: Ife6d1252373f493a597398ee51e7b5695b708df5
Reviewed-on: https://go-review.googlesource.com/c/go/+/201205
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Part 1: CL 199499 (GOOS nacl)
Part 2: CL 200077 (amd64p32 files, toolchain)
Part 3: stuff that arguably should've been part of Part 2, but I forgot
one of my grep patterns when splitting the original CL up into
two parts.
This one might also have interesting stuff to resurrect for any future
x32 ABI support.
Updates #30439
Change-Id: I2b4143374a253a003666f3c69e776b7e456bdb9c
Reviewed-on: https://go-review.googlesource.com/c/go/+/200318
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This is part two if the nacl removal. Part 1 was CL 199499.
This CL removes amd64p32 support, which might be useful in the future
if we implement the x32 ABI. It also removes the nacl bits in the
toolchain, and some remaining nacl bits.
Updates #30439
Change-Id: I2475d5bb066d1b474e00e40d95b520e7c2e286e1
Reviewed-on: https://go-review.googlesource.com/c/go/+/200077
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This allows to inline the common case in which the Source is a
rngSource. On linux/amd64 in a VM:
name old time/op new time/op delta
Read3-4 33.8ns ± 8% 18.5ns ± 8% -45.38% (p=0.000 n=10+10)
Read64-4 371ns ± 8% 70ns ± 7% -81.00% (p=0.000 n=10+10)
Read1000-4 5.33µs ± 5% 0.86µs ± 3% -83.85% (p=0.000 n=9+9)
Change-Id: Ibf47b0e9ecdfe62ffcb66d6a92f191800bdc740e
Reviewed-on: https://go-review.googlesource.com/c/go/+/191539
Reviewed-by: Daniel Martí <mvdan@mvdan.cc>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Avoid interface calls, enable inlining, and store the rngSource close to the
Mutex to exploit better memory locality.
Also add a benchmark to properly measure the threadsafe nature of globalRand.
On a linux/amd64 VM:
name old time/op new time/op delta
Int63Threadsafe-4 36.4ns ±12% 20.6ns ±11% -43.52% (p=0.000 n=30+30)
Int63ThreadsafeParallel-4 79.3ns ± 5% 56.5ns ± 5% -28.69% (p=0.000 n=29+30)
Change-Id: I6ab912c1a1e9afc7bacd8e72c82d4d50d546a510
Reviewed-on: https://go-review.googlesource.com/c/go/+/191538
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>
Run-TryBot: Emmanuel Odeke <emm.odeke@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Use the following (suboptimal) script to obtain a list of possible
typos:
#!/usr/bin/env sh
set -x
git ls-files |\
grep -e '\.\(c\|cc\|go\)$' |\
xargs -n 1\
awk\
'/\/\// { gsub(/.*\/\//, ""); print; } /\/\*/, /\*\// { gsub(/.*\/\*/, ""); gsub(/\*\/.*/, ""); }' |\
hunspell -d en_US -l |\
grep '^[[:upper:]]\{0,1\}[[:lower:]]\{1,\}$' |\
grep -v -e '^.\{1,4\}$' -e '^.\{16,\}$' |\
sort -f |\
uniq -c |\
awk '$1 == 1 { print $2; }'
Then, go through the results manually and fix the most obvious typos in
the non-vendored code.
Change-Id: I3cb5830a176850e1a0584b8a40b47bde7b260eae
Reviewed-on: https://go-review.googlesource.com/c/go/+/193848
Reviewed-by: Robert Griesemer <gri@golang.org>
math/big.Int Cmp method does not have a fast path for the case if x and y are the same.
Fixes#30856
Change-Id: Ia9a5b5f72db9d73af1b13ed6ac39ecff87d10393
Reviewed-on: https://go-review.googlesource.com/c/go/+/178957
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
The old code only normalized decimal integer imaginary number
literals. But with the generalized imaginary number syntax,
the number value may be decimal, binary, octal, or hexadecimal,
integer or floating-point.
The new code only looks at the number pattern. Only for decimal
integer imaginary literals do we need to strip leading zeroes.
The remaining normalization code simply ignore the 'i' suffix.
As a result, the new code is both simpler and shorter.
Fixes#32718.
Change-Id: If43fc962a48ed62002e65d5c81fddbb9bd283984
Reviewed-on: https://go-review.googlesource.com/c/go/+/183378
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Shorten some of the longest tests that run during all.bash.
Removes 7r 50u 21s from all.bash.
After this change, all.bash is under 5 minutes again on my laptop.
For #26473.
Change-Id: Ie0460aa935808d65460408feaed210fbaa1d5d79
Reviewed-on: https://go-review.googlesource.com/c/go/+/177559
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
For the case where the addresses of parameter z and x of the function
shlVU overlap and the address of z is greater than x, x (input value)
can be polluted during the calculation when the high words of x are
overlapped with the low words of z (output value).
Fixes#31084
Change-Id: I9bb0266a1d7856b8faa9a9b1975d6f57dece0479
Reviewed-on: https://go-review.googlesource.com/c/go/+/169780
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Int.String had no documentation and the documentation for Int.Text
did not mention the handling of the nil pointer case.
Change-Id: I9f21921e431c948545b7cabc7829e4b4e574bbe9
Reviewed-on: https://go-review.googlesource.com/c/go/+/175118
Reviewed-by: Robert Griesemer <gri@golang.org>
Where assembly functions are just jumps to the Go implementation
put them into a stubs_<arch>.s file. This reduces the number of
files considerably and makes it easier to see what is really
implemented in assembly.
I've also run the stubs files through asmfmt to format them in
a more consistent way.
Eventually we should replace these 'stub' assembly files with
a pure Go implementation now that we have mid-stack inlining
(see #31362).
Change-Id: If5b2022dcc23e1299f1b7ba79884f1b1263d0f7f
Reviewed-on: https://go-review.googlesource.com/c/go/+/173398
Run-TryBot: Michael Munday <mike.munday@ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Though there is variation in the spelling of canceled,
cancellation is always spelled with a double l.
Reference: https://www.grammarly.com/blog/canceled-vs-cancelled/
Change-Id: I240f1a297776c8e27e74f3eca566d2bc4c856f2f
Reviewed-on: https://go-review.googlesource.com/c/go/+/170060
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Mnemonics for these instructions were added to the assembler in
CL 159357.
Change-Id: Ie11c45ecc9cead9a8850fcc929b0211cfd980fe5
Reviewed-on: https://go-review.googlesource.com/c/go/+/160157
Run-TryBot: Michael Munday <mike.munday@ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Rearranged code slightly to make lifetime of underlying array of
pow5 more explicit in code.
Fixes#31184.
Change-Id: I063081f0e54097c499988d268a23813746592654
Reviewed-on: https://go-review.googlesource.com/c/go/+/170641
Reviewed-by: Filippo Valsorda <filippo@golang.org>
If x does not have an inverse modulo m, and a negative exponent is used,
return nil just like ModInverse does now.
Change-Id: I8fa72f7a851e8cf77c5fab529ede88408740626f
Reviewed-on: https://go-review.googlesource.com/c/go/+/170757
Run-TryBot: Filippo Valsorda <filippo@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
When building as part of the bootstrap process, avoid
use of "go:linkname" applied to variables, since this
feature is ill-defined/unsupported for gccgo.
Updates #30771.
Change-Id: Id44d01b5c98d292702e5075674117518cb59e2d0
Reviewed-on: https://go-review.googlesource.com/c/go/+/170737
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This addresses the failures we have seen in #31084. The correct
fix is to find the actual bug in the assembly code.
Updates #31084.
Change-Id: I437780c53d0c4423d742e2e3b650b899ce845372
Reviewed-on: https://go-review.googlesource.com/c/go/+/169721
Run-TryBot: Robert Griesemer <gri@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Implemented via the underlying Int.SetUint64.
Added tests for Rat.SetInt64 and Rat.SetUint64.
Fixes#29579
Change-Id: I03faaffc93e36873b202b58ae72b139dea5c40f9
Reviewed-on: https://go-review.googlesource.com/c/go/+/160682
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
Filippo Valsorda
Robert Griesemer
Joel Sing
Brad Fitzpatrick
Ville Skyttä
Rémy Oudompheng
Ian Lance Taylor
Brian Kessler
Russ Cox
Akhil Indurti
Alberto Donizetti
Carlo Alberto Ferraris
Javier
Ainar Garipov
peter zhang
Eric Lagergren
Illya Yalovyy
Michael Brandenburg
adarsh ravichandran
JT Olio
erifan01
Michael Munday
Josh Bleecher Snyder
Neven Sajko
Than McIntosh