Adding upstream version 1.18.10.upstream/1.18.10upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

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)
+			}
+		})
+	}
+}