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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"
"cmd/internal/src"
"testing"
)
func TestDeadStore(t *testing.T) {
c := testConfig(t)
ptrType := c.config.Types.BytePtr
t.Logf("PTRTYPE %v", ptrType)
fun := c.Fun("entry",
Bloc("entry",
Valu("start", OpInitMem, types.TypeMem, 0, nil),
Valu("sb", OpSB, c.config.Types.Uintptr, 0, nil),
Valu("v", OpConstBool, c.config.Types.Bool, 1, nil),
Valu("addr1", OpAddr, ptrType, 0, nil, "sb"),
Valu("addr2", OpAddr, ptrType, 0, nil, "sb"),
Valu("addr3", OpAddr, ptrType, 0, nil, "sb"),
Valu("zero1", OpZero, types.TypeMem, 1, c.config.Types.Bool, "addr3", "start"),
Valu("store1", OpStore, types.TypeMem, 0, c.config.Types.Bool, "addr1", "v", "zero1"),
Valu("store2", OpStore, types.TypeMem, 0, c.config.Types.Bool, "addr2", "v", "store1"),
Valu("store3", OpStore, types.TypeMem, 0, c.config.Types.Bool, "addr1", "v", "store2"),
Valu("store4", OpStore, types.TypeMem, 0, c.config.Types.Bool, "addr3", "v", "store3"),
Goto("exit")),
Bloc("exit",
Exit("store3")))
CheckFunc(fun.f)
dse(fun.f)
CheckFunc(fun.f)
v1 := fun.values["store1"]
if v1.Op != OpCopy {
t.Errorf("dead store not removed")
}
v2 := fun.values["zero1"]
if v2.Op != OpCopy {
t.Errorf("dead store (zero) not removed")
}
}
func TestDeadStorePhi(t *testing.T) {
// make sure we don't get into an infinite loop with phi values.
c := testConfig(t)
ptrType := c.config.Types.BytePtr
fun := c.Fun("entry",
Bloc("entry",
Valu("start", OpInitMem, types.TypeMem, 0, nil),
Valu("sb", OpSB, c.config.Types.Uintptr, 0, nil),
Valu("v", OpConstBool, c.config.Types.Bool, 1, nil),
Valu("addr", OpAddr, ptrType, 0, nil, "sb"),
Goto("loop")),
Bloc("loop",
Valu("phi", OpPhi, types.TypeMem, 0, nil, "start", "store"),
Valu("store", OpStore, types.TypeMem, 0, c.config.Types.Bool, "addr", "v", "phi"),
If("v", "loop", "exit")),
Bloc("exit",
Exit("store")))
CheckFunc(fun.f)
dse(fun.f)
CheckFunc(fun.f)
}
func TestDeadStoreTypes(t *testing.T) {
// Make sure a narrow store can't shadow a wider one. We test an even
// stronger restriction, that one store can't shadow another unless the
// types of the address fields are identical (where identicalness is
// decided by the CSE pass).
c := testConfig(t)
t1 := c.config.Types.UInt64.PtrTo()
t2 := c.config.Types.UInt32.PtrTo()
fun := c.Fun("entry",
Bloc("entry",
Valu("start", OpInitMem, types.TypeMem, 0, nil),
Valu("sb", OpSB, c.config.Types.Uintptr, 0, nil),
Valu("v", OpConstBool, c.config.Types.Bool, 1, nil),
Valu("addr1", OpAddr, t1, 0, nil, "sb"),
Valu("addr2", OpAddr, t2, 0, nil, "sb"),
Valu("store1", OpStore, types.TypeMem, 0, c.config.Types.Bool, "addr1", "v", "start"),
Valu("store2", OpStore, types.TypeMem, 0, c.config.Types.Bool, "addr2", "v", "store1"),
Goto("exit")),
Bloc("exit",
Exit("store2")))
CheckFunc(fun.f)
cse(fun.f)
dse(fun.f)
CheckFunc(fun.f)
v := fun.values["store1"]
if v.Op == OpCopy {
t.Errorf("store %s incorrectly removed", v)
}
}
func TestDeadStoreUnsafe(t *testing.T) {
// Make sure a narrow store can't shadow a wider one. The test above
// covers the case of two different types, but unsafe pointer casting
// can get to a point where the size is changed but type unchanged.
c := testConfig(t)
ptrType := c.config.Types.UInt64.PtrTo()
fun := c.Fun("entry",
Bloc("entry",
Valu("start", OpInitMem, types.TypeMem, 0, nil),
Valu("sb", OpSB, c.config.Types.Uintptr, 0, nil),
Valu("v", OpConstBool, c.config.Types.Bool, 1, nil),
Valu("addr1", OpAddr, ptrType, 0, nil, "sb"),
Valu("store1", OpStore, types.TypeMem, 0, c.config.Types.Int64, "addr1", "v", "start"), // store 8 bytes
Valu("store2", OpStore, types.TypeMem, 0, c.config.Types.Bool, "addr1", "v", "store1"), // store 1 byte
Goto("exit")),
Bloc("exit",
Exit("store2")))
CheckFunc(fun.f)
cse(fun.f)
dse(fun.f)
CheckFunc(fun.f)
v := fun.values["store1"]
if v.Op == OpCopy {
t.Errorf("store %s incorrectly removed", v)
}
}
func TestDeadStoreSmallStructInit(t *testing.T) {
c := testConfig(t)
ptrType := c.config.Types.BytePtr
typ := types.NewStruct([]*types.Field{
types.NewField(src.NoXPos, &types.Sym{Name: "A"}, c.config.Types.Int),
types.NewField(src.NoXPos, &types.Sym{Name: "B"}, c.config.Types.Int),
})
name := c.Temp(typ)
fun := c.Fun("entry",
Bloc("entry",
Valu("start", OpInitMem, types.TypeMem, 0, nil),
Valu("sp", OpSP, c.config.Types.Uintptr, 0, nil),
Valu("zero", OpConst64, c.config.Types.Int, 0, nil),
Valu("v6", OpLocalAddr, ptrType, 0, name, "sp", "start"),
Valu("v3", OpOffPtr, ptrType, 8, nil, "v6"),
Valu("v22", OpOffPtr, ptrType, 0, nil, "v6"),
Valu("zerostore1", OpStore, types.TypeMem, 0, c.config.Types.Int, "v22", "zero", "start"),
Valu("zerostore2", OpStore, types.TypeMem, 0, c.config.Types.Int, "v3", "zero", "zerostore1"),
Valu("v8", OpLocalAddr, ptrType, 0, name, "sp", "zerostore2"),
Valu("v23", OpOffPtr, ptrType, 8, nil, "v8"),
Valu("v25", OpOffPtr, ptrType, 0, nil, "v8"),
Valu("zerostore3", OpStore, types.TypeMem, 0, c.config.Types.Int, "v25", "zero", "zerostore2"),
Valu("zerostore4", OpStore, types.TypeMem, 0, c.config.Types.Int, "v23", "zero", "zerostore3"),
Goto("exit")),
Bloc("exit",
Exit("zerostore4")))
fun.f.Name = "smallstructinit"
CheckFunc(fun.f)
cse(fun.f)
dse(fun.f)
CheckFunc(fun.f)
v1 := fun.values["zerostore1"]
if v1.Op != OpCopy {
t.Errorf("dead store not removed")
}
v2 := fun.values["zerostore2"]
if v2.Op != OpCopy {
t.Errorf("dead store not removed")
}
}