diff options
| -rw-r--r-- | src/cmd/compile/internal/ssa/deadstore.go | 19 | ||||
| -rw-r--r-- | src/cmd/compile/internal/ssa/deadstore_test.go | 45 |
2 files changed, 64 insertions, 0 deletions
diff --git a/src/cmd/compile/internal/ssa/deadstore.go b/src/cmd/compile/internal/ssa/deadstore.go index cb3427103c..ce04cb3a24 100644 --- a/src/cmd/compile/internal/ssa/deadstore.go +++ b/src/cmd/compile/internal/ssa/deadstore.go @@ -21,12 +21,18 @@ func dse(f *Func) { defer f.retSparseSet(storeUse) shadowed := f.newSparseMap(f.NumValues()) defer f.retSparseMap(shadowed) + // localAddrs maps from a local variable (the Aux field of a LocalAddr value) to an instance of a LocalAddr value for that variable in the current block. + localAddrs := map[any]*Value{} for _, b := range f.Blocks { // Find all the stores in this block. Categorize their uses: // loadUse contains stores which are used by a subsequent load. // storeUse contains stores which are used by a subsequent store. loadUse.clear() storeUse.clear() + // TODO(deparker): use the 'clear' builtin once compiler bootstrap minimum version is raised to 1.21. + for k := range localAddrs { + delete(localAddrs, k) + } stores = stores[:0] for _, v := range b.Values { if v.Op == OpPhi { @@ -46,6 +52,13 @@ func dse(f *Func) { } } } else { + if v.Op == OpLocalAddr { + if _, ok := localAddrs[v.Aux]; !ok { + localAddrs[v.Aux] = v + } else { + continue + } + } for _, a := range v.Args { if a.Block == b && a.Type.IsMemory() { loadUse.add(a.ID) @@ -100,6 +113,11 @@ func dse(f *Func) { } else { // OpZero sz = v.AuxInt } + if ptr.Op == OpLocalAddr { + if la, ok := localAddrs[ptr.Aux]; ok { + ptr = la + } + } sr := shadowRange(shadowed.get(ptr.ID)) if sr.contains(off, off+sz) { // Modify the store/zero into a copy of the memory state, @@ -146,6 +164,7 @@ type shadowRange int32 func (sr shadowRange) lo() int64 { return int64(sr & 0xffff) } + func (sr shadowRange) hi() int64 { return int64((sr >> 16) & 0xffff) } diff --git a/src/cmd/compile/internal/ssa/deadstore_test.go b/src/cmd/compile/internal/ssa/deadstore_test.go index 33cb4b9755..4ccd6b8e91 100644 --- a/src/cmd/compile/internal/ssa/deadstore_test.go +++ b/src/cmd/compile/internal/ssa/deadstore_test.go @@ -6,6 +6,7 @@ package ssa import ( "cmd/compile/internal/types" + "cmd/internal/src" "testing" ) @@ -44,6 +45,7 @@ func TestDeadStore(t *testing.T) { 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) @@ -127,3 +129,46 @@ func TestDeadStoreUnsafe(t *testing.T) { 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") + } +} |