diff options
Diffstat (limited to 'src/cmd/compile/internal/ssa/branchelim_test.go')
| -rw-r--r-- | src/cmd/compile/internal/ssa/branchelim_test.go | 172 |
1 files changed, 172 insertions, 0 deletions
diff --git a/src/cmd/compile/internal/ssa/branchelim_test.go b/src/cmd/compile/internal/ssa/branchelim_test.go new file mode 100644 index 0000000..20fa84d --- /dev/null +++ b/src/cmd/compile/internal/ssa/branchelim_test.go @@ -0,0 +1,172 @@ +// Copyright 2017 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" + "testing" +) + +// Test that a trivial 'if' is eliminated +func TestBranchElimIf(t *testing.T) { + var testData = []struct { + arch string + intType string + ok bool + }{ + {"arm64", "int32", true}, + {"amd64", "int32", true}, + {"amd64", "int8", false}, + } + + for _, data := range testData { + t.Run(data.arch+"/"+data.intType, func(t *testing.T) { + c := testConfigArch(t, data.arch) + boolType := c.config.Types.Bool + var intType *types.Type + switch data.intType { + case "int32": + intType = c.config.Types.Int32 + case "int8": + intType = c.config.Types.Int8 + default: + t.Fatal("invalid integer type:", data.intType) + } + fun := c.Fun("entry", + Bloc("entry", + Valu("start", OpInitMem, types.TypeMem, 0, nil), + Valu("sb", OpSB, c.config.Types.Uintptr, 0, nil), + Valu("const1", OpConst32, intType, 1, nil), + Valu("const2", OpConst32, intType, 2, nil), + Valu("addr", OpAddr, boolType.PtrTo(), 0, nil, "sb"), + Valu("cond", OpLoad, boolType, 0, nil, "addr", "start"), + If("cond", "b2", "b3")), + Bloc("b2", + Goto("b3")), + Bloc("b3", + Valu("phi", OpPhi, intType, 0, nil, "const1", "const2"), + Valu("retstore", OpStore, types.TypeMem, 0, nil, "phi", "sb", "start"), + Exit("retstore"))) + + CheckFunc(fun.f) + branchelim(fun.f) + CheckFunc(fun.f) + Deadcode(fun.f) + CheckFunc(fun.f) + + if data.ok { + + if len(fun.f.Blocks) != 1 { + t.Fatalf("expected 1 block after branchelim and deadcode; found %d", len(fun.f.Blocks)) + } + if fun.values["phi"].Op != OpCondSelect { + t.Fatalf("expected phi op to be CondSelect; found op %s", fun.values["phi"].Op) + } + if fun.values["phi"].Args[2] != fun.values["cond"] { + t.Errorf("expected CondSelect condition to be %s; found %s", fun.values["cond"], fun.values["phi"].Args[2]) + } + if fun.blocks["entry"].Kind != BlockExit { + t.Errorf("expected entry to be BlockExit; found kind %s", fun.blocks["entry"].Kind.String()) + } + } else { + if len(fun.f.Blocks) != 3 { + t.Fatalf("expected 3 block after branchelim and deadcode; found %d", len(fun.f.Blocks)) + } + } + }) + } +} + +// Test that a trivial if/else is eliminated +func TestBranchElimIfElse(t *testing.T) { + for _, arch := range []string{"arm64", "amd64"} { + t.Run(arch, func(t *testing.T) { + c := testConfigArch(t, arch) + boolType := c.config.Types.Bool + intType := c.config.Types.Int32 + fun := c.Fun("entry", + Bloc("entry", + Valu("start", OpInitMem, types.TypeMem, 0, nil), + Valu("sb", OpSB, c.config.Types.Uintptr, 0, nil), + Valu("const1", OpConst32, intType, 1, nil), + Valu("const2", OpConst32, intType, 2, nil), + Valu("addr", OpAddr, boolType.PtrTo(), 0, nil, "sb"), + Valu("cond", OpLoad, boolType, 0, nil, "addr", "start"), + If("cond", "b2", "b3")), + Bloc("b2", + Goto("b4")), + Bloc("b3", + Goto("b4")), + Bloc("b4", + Valu("phi", OpPhi, intType, 0, nil, "const1", "const2"), + Valu("retstore", OpStore, types.TypeMem, 0, nil, "phi", "sb", "start"), + Exit("retstore"))) + + CheckFunc(fun.f) + branchelim(fun.f) + CheckFunc(fun.f) + Deadcode(fun.f) + CheckFunc(fun.f) + + if len(fun.f.Blocks) != 1 { + t.Fatalf("expected 1 block after branchelim; found %d", len(fun.f.Blocks)) + } + if fun.values["phi"].Op != OpCondSelect { + t.Fatalf("expected phi op to be CondSelect; found op %s", fun.values["phi"].Op) + } + if fun.values["phi"].Args[2] != fun.values["cond"] { + t.Errorf("expected CondSelect condition to be %s; found %s", fun.values["cond"], fun.values["phi"].Args[2]) + } + if fun.blocks["entry"].Kind != BlockExit { + t.Errorf("expected entry to be BlockExit; found kind %s", fun.blocks["entry"].Kind.String()) + } + }) + } +} + +// Test that an if/else CFG that loops back +// into itself does *not* get eliminated. +func TestNoBranchElimLoop(t *testing.T) { + for _, arch := range []string{"arm64", "amd64"} { + t.Run(arch, func(t *testing.T) { + c := testConfigArch(t, arch) + boolType := c.config.Types.Bool + intType := c.config.Types.Int32 + + // The control flow here is totally bogus, + // but a dead cycle seems like the only plausible + // way to arrive at a diamond CFG that is also a loop. + fun := c.Fun("entry", + Bloc("entry", + Valu("start", OpInitMem, types.TypeMem, 0, nil), + Valu("sb", OpSB, c.config.Types.Uintptr, 0, nil), + Valu("const2", OpConst32, intType, 2, nil), + Valu("const3", OpConst32, intType, 3, nil), + Goto("b5")), + Bloc("b2", + Valu("addr", OpAddr, boolType.PtrTo(), 0, nil, "sb"), + Valu("cond", OpLoad, boolType, 0, nil, "addr", "start"), + Valu("phi", OpPhi, intType, 0, nil, "const2", "const3"), + If("cond", "b3", "b4")), + Bloc("b3", + Goto("b2")), + Bloc("b4", + Goto("b2")), + Bloc("b5", + Exit("start"))) + + CheckFunc(fun.f) + branchelim(fun.f) + CheckFunc(fun.f) + + if len(fun.f.Blocks) != 5 { + t.Errorf("expected 5 block after branchelim; found %d", len(fun.f.Blocks)) + } + if fun.values["phi"].Op != OpPhi { + t.Errorf("expected phi op to be CondSelect; found op %s", fun.values["phi"].Op) + } + }) + } +} |