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go/test/codegen/compare_and_branch.go
Michael Munday 85d54a7667 cmd/compile: use zero constants in comparisons where possible
Some integer comparisons with 1 and -1 can be rewritten as comparisons
with 0. For example, x < 1 is equivalent to x <= 0. This is an
advantageous transformation on riscv64 because comparisons with zero
do not require a constant to be loaded into a register. Other
architectures will likely benefit too and the transformation is
relatively benign on architectures that do not benefit.

Change-Id: I2ce9821dd7605a660eb71d76e83a61f9bae1bf25
Reviewed-on: https://go-review.googlesource.com/c/go/+/350831
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Run-TryBot: Michael Munday <mike.munday@lowrisc.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
2023-02-27 21:38:30 +00:00

243 lines
4.2 KiB
Go

// asmcheck
// Copyright 2019 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
//go:noinline
func dummy() {}
// Signed 64-bit compare-and-branch.
func si64(x, y chan int64) {
// s390x:"CGRJ\t[$](2|4), R[0-9]+, R[0-9]+, "
for <-x < <-y {
dummy()
}
// s390x:"CL?GRJ\t[$]8, R[0-9]+, R[0-9]+, "
for <-x == <-y {
dummy()
}
}
// Signed 64-bit compare-and-branch with 8-bit immediate.
func si64x8() {
// s390x:"CGIJ\t[$]12, R[0-9]+, [$]127, "
for i := int64(0); i < 128; i++ {
dummy()
}
// s390x:"CGIJ\t[$]10, R[0-9]+, [$]-128, "
for i := int64(0); i > -129; i-- {
dummy()
}
// s390x:"CGIJ\t[$]2, R[0-9]+, [$]127, "
for i := int64(0); i >= 128; i++ {
dummy()
}
// s390x:"CGIJ\t[$]4, R[0-9]+, [$]-128, "
for i := int64(0); i <= -129; i-- {
dummy()
}
}
// Unsigned 64-bit compare-and-branch.
func ui64(x, y chan uint64) {
// s390x:"CLGRJ\t[$](2|4), R[0-9]+, R[0-9]+, "
for <-x > <-y {
dummy()
}
// s390x:"CL?GRJ\t[$]6, R[0-9]+, R[0-9]+, "
for <-x != <-y {
dummy()
}
}
// Unsigned 64-bit comparison with 8-bit immediate.
func ui64x8() {
// s390x:"CLGIJ\t[$]4, R[0-9]+, [$]128, "
for i := uint64(0); i < 128; i++ {
dummy()
}
// s390x:"CLGIJ\t[$]12, R[0-9]+, [$]255, "
for i := uint64(0); i < 256; i++ {
dummy()
}
// s390x:"CLGIJ\t[$]2, R[0-9]+, [$]255, "
for i := uint64(0); i >= 256; i-- {
dummy()
}
// s390x:"CLGIJ\t[$]2, R[0-9]+, [$]0, "
for i := uint64(1024); i > 0; i-- {
dummy()
}
}
// Signed 32-bit compare-and-branch.
func si32(x, y chan int32) {
// s390x:"CRJ\t[$](2|4), R[0-9]+, R[0-9]+, "
for <-x < <-y {
dummy()
}
// s390x:"CL?RJ\t[$]8, R[0-9]+, R[0-9]+, "
for <-x == <-y {
dummy()
}
}
// Signed 32-bit compare-and-branch with 8-bit immediate.
func si32x8() {
// s390x:"CIJ\t[$]12, R[0-9]+, [$]127, "
for i := int32(0); i < 128; i++ {
dummy()
}
// s390x:"CIJ\t[$]10, R[0-9]+, [$]-128, "
for i := int32(0); i > -129; i-- {
dummy()
}
// s390x:"CIJ\t[$]2, R[0-9]+, [$]127, "
for i := int32(0); i >= 128; i++ {
dummy()
}
// s390x:"CIJ\t[$]4, R[0-9]+, [$]-128, "
for i := int32(0); i <= -129; i-- {
dummy()
}
}
// Unsigned 32-bit compare-and-branch.
func ui32(x, y chan uint32) {
// s390x:"CLRJ\t[$](2|4), R[0-9]+, R[0-9]+, "
for <-x > <-y {
dummy()
}
// s390x:"CL?RJ\t[$]6, R[0-9]+, R[0-9]+, "
for <-x != <-y {
dummy()
}
}
// Unsigned 32-bit comparison with 8-bit immediate.
func ui32x8() {
// s390x:"CLIJ\t[$]4, R[0-9]+, [$]128, "
for i := uint32(0); i < 128; i++ {
dummy()
}
// s390x:"CLIJ\t[$]12, R[0-9]+, [$]255, "
for i := uint32(0); i < 256; i++ {
dummy()
}
// s390x:"CLIJ\t[$]2, R[0-9]+, [$]255, "
for i := uint32(0); i >= 256; i-- {
dummy()
}
// s390x:"CLIJ\t[$]2, R[0-9]+, [$]0, "
for i := uint32(1024); i > 0; i-- {
dummy()
}
}
// Signed 64-bit comparison with unsigned 8-bit immediate.
func si64xu8(x chan int64) {
// s390x:"CLGIJ\t[$]8, R[0-9]+, [$]128, "
for <-x == 128 {
dummy()
}
// s390x:"CLGIJ\t[$]6, R[0-9]+, [$]255, "
for <-x != 255 {
dummy()
}
}
// Signed 32-bit comparison with unsigned 8-bit immediate.
func si32xu8(x chan int32) {
// s390x:"CLIJ\t[$]8, R[0-9]+, [$]255, "
for <-x == 255 {
dummy()
}
// s390x:"CLIJ\t[$]6, R[0-9]+, [$]128, "
for <-x != 128 {
dummy()
}
}
// Unsigned 64-bit comparison with signed 8-bit immediate.
func ui64xu8(x chan uint64) {
// s390x:"CGIJ\t[$]8, R[0-9]+, [$]-1, "
for <-x == ^uint64(0) {
dummy()
}
// s390x:"CGIJ\t[$]6, R[0-9]+, [$]-128, "
for <-x != ^uint64(127) {
dummy()
}
}
// Unsigned 32-bit comparison with signed 8-bit immediate.
func ui32xu8(x chan uint32) {
// s390x:"CIJ\t[$]8, R[0-9]+, [$]-128, "
for <-x == ^uint32(127) {
dummy()
}
// s390x:"CIJ\t[$]6, R[0-9]+, [$]-1, "
for <-x != ^uint32(0) {
dummy()
}
}
// Signed 64-bit comparison with 1/-1 to comparison with 0.
func si64x0(x chan int64) {
// riscv64:"BGTZ"
for <-x >= 1 {
dummy()
}
// riscv64:"BLEZ"
for <-x < 1 {
dummy()
}
// riscv64:"BLTZ"
for <-x <= -1 {
dummy()
}
// riscv64:"BGEZ"
for <-x > -1 {
dummy()
}
}
// Unsigned 64-bit comparison with 1 to comparison with 0.
func ui64x0(x chan uint64) {
// riscv64:"BNEZ"
for <-x >= 1 {
dummy()
}
// riscv64:"BEQZ"
for <-x < 1 {
dummy()
}
}