go/test/codegen/condmove.go
fanzha02 f5e6d3e879 cmd/compile: add rewrite rules for conditional instructions on arm64
This CL adds rewrite rules for CSETM, CSINC, CSINV, and CSNEG. By adding
these rules, we can save one instruction.

For example,

  func test(cond bool, a int) int {
    if cond {
      a++
    }
    return a
  }

Before:

  MOVD "".a+8(RSP), R0
  ADD $1, R0, R1
  MOVBU "".cond(RSP), R2
  CMPW $0, R2
  CSEL NE, R1, R0, R0

After:

  MOVBU "".cond(RSP), R0
  CMPW $0, R0
  MOVD "".a+8(RSP), R0
  CSINC EQ, R0, R0, R0

This patch is a copy of CL 285694. Co-authored-by: JunchenLi
<junchen.li@arm.com>

Change-Id: Ic1a79e8b8ece409b533becfcb7950f11e7b76f24
Reviewed-on: https://go-review.googlesource.com/c/go/+/302231
Trust: fannie zhang <Fannie.Zhang@arm.com>
Run-TryBot: fannie zhang <Fannie.Zhang@arm.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
2021-03-18 01:46:58 +00:00

403 lines
5.3 KiB
Go

// asmcheck
// Copyright 2018 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package codegen
func cmovint(c int) int {
x := c + 4
if x < 0 {
x = 182
}
// amd64:"CMOVQLT"
// arm64:"CSEL\tLT"
// wasm:"Select"
return x
}
func cmovchan(x, y chan int) chan int {
if x != y {
x = y
}
// amd64:"CMOVQNE"
// arm64:"CSEL\tNE"
// wasm:"Select"
return x
}
func cmovuintptr(x, y uintptr) uintptr {
if x < y {
x = -y
}
// amd64:"CMOVQ(HI|CS)"
// arm64:"CSNEG\tLS"
// wasm:"Select"
return x
}
func cmov32bit(x, y uint32) uint32 {
if x < y {
x = -y
}
// amd64:"CMOVL(HI|CS)"
// arm64:"CSNEG\t(LS|HS)"
// wasm:"Select"
return x
}
func cmov16bit(x, y uint16) uint16 {
if x < y {
x = -y
}
// amd64:"CMOVW(HI|CS)"
// arm64:"CSNEG\t(LS|HS)"
// wasm:"Select"
return x
}
// Floating point comparison. For EQ/NE, we must
// generate special code to handle NaNs.
func cmovfloateq(x, y float64) int {
a := 128
if x == y {
a = 256
}
// amd64:"CMOVQNE","CMOVQPC"
// arm64:"CSEL\tEQ"
// wasm:"Select"
return a
}
func cmovfloatne(x, y float64) int {
a := 128
if x != y {
a = 256
}
// amd64:"CMOVQNE","CMOVQPS"
// arm64:"CSEL\tNE"
// wasm:"Select"
return a
}
//go:noinline
func frexp(f float64) (frac float64, exp int) {
return 1.0, 4
}
//go:noinline
func ldexp(frac float64, exp int) float64 {
return 1.0
}
// Generate a CMOV with a floating comparison and integer move.
func cmovfloatint2(x, y float64) float64 {
yfr, yexp := 4.0, 5
r := x
for r >= y {
rfr, rexp := frexp(r)
if rfr < yfr {
rexp = rexp - 1
}
// amd64:"CMOVQHI"
// arm64:"CSEL\tMI"
// wasm:"Select"
r = r - ldexp(y, rexp-yexp)
}
return r
}
func cmovloaded(x [4]int, y int) int {
if x[2] != 0 {
y = x[2]
} else {
y = y >> 2
}
// amd64:"CMOVQNE"
// arm64:"CSEL\tNE"
// wasm:"Select"
return y
}
func cmovuintptr2(x, y uintptr) uintptr {
a := x * 2
if a == 0 {
a = 256
}
// amd64:"CMOVQEQ"
// arm64:"CSEL\tEQ"
// wasm:"Select"
return a
}
// Floating point CMOVs are not supported by amd64/arm64
func cmovfloatmove(x, y int) float64 {
a := 1.0
if x <= y {
a = 2.0
}
// amd64:-"CMOV"
// arm64:-"CSEL"
// wasm:-"Select"
return a
}
// On amd64, the following patterns trigger comparison inversion.
// Test that we correctly invert the CMOV condition
var gsink int64
var gusink uint64
func cmovinvert1(x, y int64) int64 {
if x < gsink {
y = -y
}
// amd64:"CMOVQGT"
return y
}
func cmovinvert2(x, y int64) int64 {
if x <= gsink {
y = -y
}
// amd64:"CMOVQGE"
return y
}
func cmovinvert3(x, y int64) int64 {
if x == gsink {
y = -y
}
// amd64:"CMOVQEQ"
return y
}
func cmovinvert4(x, y int64) int64 {
if x != gsink {
y = -y
}
// amd64:"CMOVQNE"
return y
}
func cmovinvert5(x, y uint64) uint64 {
if x > gusink {
y = -y
}
// amd64:"CMOVQCS"
return y
}
func cmovinvert6(x, y uint64) uint64 {
if x >= gusink {
y = -y
}
// amd64:"CMOVQLS"
return y
}
func cmovload(a []int, i int, b bool) int {
if b {
i++
}
// See issue 26306
// amd64:-"CMOVQNE"
return a[i]
}
func cmovstore(a []int, i int, b bool) {
if b {
i++
}
// amd64:"CMOVQNE"
a[i] = 7
}
var r0, r1, r2, r3, r4, r5 int
func cmovinc(cond bool, a, b, c int) {
var x0, x1 int
if cond {
x0 = a
} else {
x0 = b + 1
}
// arm64:"CSINC\tNE", -"CSEL"
r0 = x0
if cond {
x1 = b + 1
} else {
x1 = a
}
// arm64:"CSINC\tEQ", -"CSEL"
r1 = x1
if cond {
c++
}
// arm64:"CSINC\tEQ", -"CSEL"
r2 = c
}
func cmovinv(cond bool, a, b int) {
var x0, x1 int
if cond {
x0 = a
} else {
x0 = ^b
}
// arm64:"CSINV\tNE", -"CSEL"
r0 = x0
if cond {
x1 = ^b
} else {
x1 = a
}
// arm64:"CSINV\tEQ", -"CSEL"
r1 = x1
}
func cmovneg(cond bool, a, b, c int) {
var x0, x1 int
if cond {
x0 = a
} else {
x0 = -b
}
// arm64:"CSNEG\tNE", -"CSEL"
r0 = x0
if cond {
x1 = -b
} else {
x1 = a
}
// arm64:"CSNEG\tEQ", -"CSEL"
r1 = x1
}
func cmovsetm(cond bool, x int) {
var x0, x1 int
if cond {
x0 = -1
} else {
x0 = 0
}
// arm64:"CSETM\tNE", -"CSEL"
r0 = x0
if cond {
x1 = 0
} else {
x1 = -1
}
// arm64:"CSETM\tEQ", -"CSEL"
r1 = x1
}
func cmovFcmp0(s, t float64, a, b int) {
var x0, x1, x2, x3, x4, x5 int
if s < t {
x0 = a
} else {
x0 = b + 1
}
// arm64:"CSINC\tMI", -"CSEL"
r0 = x0
if s <= t {
x1 = a
} else {
x1 = ^b
}
// arm64:"CSINV\tLS", -"CSEL"
r1 = x1
if s > t {
x2 = a
} else {
x2 = -b
}
// arm64:"CSNEG\tMI", -"CSEL"
r2 = x2
if s >= t {
x3 = -1
} else {
x3 = 0
}
// arm64:"CSETM\tLS", -"CSEL"
r3 = x3
if s == t {
x4 = a
} else {
x4 = b + 1
}
// arm64:"CSINC\tEQ", -"CSEL"
r4 = x4
if s != t {
x5 = a
} else {
x5 = b + 1
}
// arm64:"CSINC\tNE", -"CSEL"
r5 = x5
}
func cmovFcmp1(s, t float64, a, b int) {
var x0, x1, x2, x3, x4, x5 int
if s < t {
x0 = b + 1
} else {
x0 = a
}
// arm64:"CSINC\tPL", -"CSEL"
r0 = x0
if s <= t {
x1 = ^b
} else {
x1 = a
}
// arm64:"CSINV\tHI", -"CSEL"
r1 = x1
if s > t {
x2 = -b
} else {
x2 = a
}
// arm64:"CSNEG\tPL", -"CSEL"
r2 = x2
if s >= t {
x3 = 0
} else {
x3 = -1
}
// arm64:"CSETM\tHI", -"CSEL"
r3 = x3
if s == t {
x4 = b + 1
} else {
x4 = a
}
// arm64:"CSINC\tNE", -"CSEL"
r4 = x4
if s != t {
x5 = b + 1
} else {
x5 = a
}
// arm64:"CSINC\tEQ", -"CSEL"
r5 = x5
}