09ed9a6585
CL 514596 adds float min/max for amd64, this CL adds it for riscv64.
The behavior of the RISC-V FMIN/FMAX instructions almost match Go's
requirements.
However according to RISCV spec 8.3 "NaN Generation and Propagation"
>> if at least one input is a signaling NaN, or if both inputs are quiet
>> NaNs, the result is the canonical NaN. If one operand is a quiet NaN
>> and the other is not a NaN, the result is the non-NaN operand.
Go using quiet NaN as NaN and according to Go spec
>> if any argument is a NaN, the result is a NaN
This requires the float min/max implementation to check whether one
of operand is qNaN before float mix/max actually execute.
This CL also fix a typo in minmax test.
Benchmark on Visionfive2
goos: linux
goarch: riscv64
pkg: runtime
│ float_minmax.old.bench │ float_minmax.new.bench │
│ sec/op │ sec/op vs base │
MinFloat 158.20n ± 0% 28.13n ± 0% -82.22% (p=0.000 n=10)
MaxFloat 158.10n ± 0% 28.12n ± 0% -82.21% (p=0.000 n=10)
geomean 158.1n 28.12n -82.22%
Update #59488
Change-Id: Iab48be6d32b8882044fb8c821438ca8840e5493d
Reviewed-on: https://go-review.googlesource.com/c/go/+/514775
Reviewed-by: Mauri de Souza Meneguzzo <mauri870@gmail.com>
Run-TryBot: M Zhuo <mengzhuo1203@gmail.com>
Reviewed-by: Joel Sing <joel@sing.id.au>
Reviewed-by: Cherry Mui <cherryyz@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@google.com>
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| CONTRIBUTING.md | ||
| go.env | ||
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| README.md | ||
| SECURITY.md | ||
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