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cmd/compile: add s390x intrinsics for Ceil, Floor, Round and Trunc

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Ceil, Floor and Trunc are pre-existing intrinsics. Round is a new
function and has been added as an intrinsic in this CL. All of the
functions can be implemented as a single 'LOAD FP INTEGER'
instruction, FIDBR, on s390x.

name   old time/op  new time/op  delta
Ceil   2.34ns ± 0%  0.85ns ± 0%  -63.74%  (p=0.000 n=5+4)
Floor  2.33ns ± 0%  0.85ns ± 1%  -63.35%  (p=0.008 n=5+5)
Round  4.23ns ± 0%  0.85ns ± 0%  -79.89%  (p=0.000 n=5+4)
Trunc  2.35ns ± 0%  0.85ns ± 0%  -63.83%  (p=0.029 n=4+4)

Change-Id: Idee7ba24a2899d12bf9afee4eedd6b4aaad3c510
Reviewed-on: https://go-review.googlesource.com/63890
Run-TryBot: Michael Munday <mike.munday@ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
This commit is contained in:
Michael Munday 2017-09-14 20:00:02 +01:00
parent 8802b188c6
commit 7582494e06
8 changed files with 159 additions and 8 deletions
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21
src/cmd/compile/internal/ssa/gen/genericOps.go
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@ -255,10 +255,23 @@ var genericOps = []opData{
{name: "PopCount32", argLength: 1}, // Count bits in arg[0]
{name: "PopCount64", argLength: 1}, // Count bits in arg[0]
{name: "Sqrt", argLength: 1}, // sqrt(arg0), float64 only
{name: "Floor", argLength: 1}, // floor(arg0), float64 only
{name: "Ceil", argLength: 1}, // ceil(arg0), float64 only
{name: "Trunc", argLength: 1}, // trunc(arg0), float64 only
// Square root, float64 only.
// Special cases:
// +∞ → +∞
// ±0 → ±0 (sign preserved)
// x<0 → NaN
// NaN → NaN
{name: "Sqrt", argLength: 1}, // √arg0
// Round to integer, float64 only.
// Special cases:
// ±∞ → ±∞ (sign preserved)
// ±0 → ±0 (sign preserved)
// NaN → NaN
{name: "Floor", argLength: 1}, // round arg0 toward -∞
{name: "Ceil", argLength: 1}, // round arg0 toward +∞
{name: "Trunc", argLength: 1}, // round arg0 toward 0
{name: "Round", argLength: 1}, // round arg0 to nearest, ties away from 0
// Data movement, max argument length for Phi is indefinite so just pick
// a really large number