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// Copyright 2015 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 ssa
import (
"cmd/compile/internal/types"
"fmt"
"strconv"
"testing"
)
func TestDeadLoop(t *testing.T) {
c := testConfig(t)
fun := c.Fun("entry",
Bloc("entry",
Valu("mem", OpInitMem, types.TypeMem, 0, nil),
Goto("exit")),
Bloc("exit",
Exit("mem")),
// dead loop
Bloc("deadblock",
// dead value in dead block
Valu("deadval", OpConstBool, c.config.Types.Bool, 1, nil),
If("deadval", "deadblock", "exit")))
CheckFunc(fun.f)
Deadcode(fun.f)
CheckFunc(fun.f)
for _, b := range fun.f.Blocks {
if b == fun.blocks["deadblock"] {
t.Errorf("dead block not removed")
}
for _, v := range b.Values {
if v == fun.values["deadval"] {
t.Errorf("control value of dead block not removed")
}
}
}
}
func TestDeadValue(t *testing.T) {
c := testConfig(t)
fun := c.Fun("entry",
Bloc("entry",
Valu("mem", OpInitMem, types.TypeMem, 0, nil),
Valu("deadval", OpConst64, c.config.Types.Int64, 37, nil),
Goto("exit")),
Bloc("exit",
Exit("mem")))
CheckFunc(fun.f)
Deadcode(fun.f)
CheckFunc(fun.f)
for _, b := range fun.f.Blocks {
for _, v := range b.Values {
if v == fun.values["deadval"] {
t.Errorf("dead value not removed")
}
}
}
}
func TestNeverTaken(t *testing.T) {
c := testConfig(t)
fun := c.Fun("entry",
Bloc("entry",
Valu("cond", OpConstBool, c.config.Types.Bool, 0, nil),
Valu("mem", OpInitMem, types.TypeMem, 0, nil),
If("cond", "then", "else")),
Bloc("then",
Goto("exit")),
Bloc("else",
Goto("exit")),
Bloc("exit",
Exit("mem")))
CheckFunc(fun.f)
Opt(fun.f)
Deadcode(fun.f)
CheckFunc(fun.f)
if fun.blocks["entry"].Kind != BlockPlain {
t.Errorf("if(false) not simplified")
}
for _, b := range fun.f.Blocks {
if b == fun.blocks["then"] {
t.Errorf("then block still present")
}
for _, v := range b.Values {
if v == fun.values["cond"] {
t.Errorf("constant condition still present")
}
}
}
}
func TestNestedDeadBlocks(t *testing.T) {
c := testConfig(t)
fun := c.Fun("entry",
Bloc("entry",
Valu("mem", OpInitMem, types.TypeMem, 0, nil),
Valu("cond", OpConstBool, c.config.Types.Bool, 0, nil),
If("cond", "b2", "b4")),
Bloc("b2",
If("cond", "b3", "b4")),
Bloc("b3",
If("cond", "b3", "b4")),
Bloc("b4",
If("cond", "b3", "exit")),
Bloc("exit",
Exit("mem")))
CheckFunc(fun.f)
Opt(fun.f)
CheckFunc(fun.f)
Deadcode(fun.f)
CheckFunc(fun.f)
if fun.blocks["entry"].Kind != BlockPlain {
t.Errorf("if(false) not simplified")
}
for _, b := range fun.f.Blocks {
if b == fun.blocks["b2"] {
t.Errorf("b2 block still present")
}
if b == fun.blocks["b3"] {
t.Errorf("b3 block still present")
}
for _, v := range b.Values {
if v == fun.values["cond"] {
t.Errorf("constant condition still present")
}
}
}
}
func BenchmarkDeadCode(b *testing.B) {
for _, n := range [...]int{1, 10, 100, 1000, 10000, 100000, 200000} {
b.Run(strconv.Itoa(n), func(b *testing.B) {
c := testConfig(b)
blocks := make([]bloc, 0, n+2)
blocks = append(blocks,
Bloc("entry",
Valu("mem", OpInitMem, types.TypeMem, 0, nil),
Goto("exit")))
blocks = append(blocks, Bloc("exit", Exit("mem")))
for i := 0; i < n; i++ {
blocks = append(blocks, Bloc(fmt.Sprintf("dead%d", i), Goto("exit")))
}
b.ResetTimer()
for i := 0; i < b.N; i++ {
fun := c.Fun("entry", blocks...)
Deadcode(fun.f)
}
})
}
}