[dev.ssa] Merge remote-tracking branch 'origin/master' into mergebranch

Semi-regular merge of tip to dev.ssa.

Complicated a bit by the move of cmd/internal/* to cmd/compile/internal/*.

Change-Id: I1c66d3c29bb95cce4a53c5a3476373aa5245303d

1 files changed, 93 insertions, 0 deletions

diff --git a/src/cmd/compile/internal/ssa/deadcode_test.go b/src/cmd/compile/internal/ssa/deadcode_test.go
new file mode 100644
index 0000000000..ced46e524b
--- /dev/null
+++ b/src/cmd/compile/internal/ssa/deadcode_test.go
@@ -0,0 +1,93 @@
+// 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 (
+	"testing"
+)
+
+func TestDeadLoop(t *testing.T) {
+	fun := Fun("entry",
+		Bloc("entry",
+			Valu("mem", OpArg, TypeMem, ".mem"),
+			Goto("exit")),
+		Bloc("exit",
+			Exit("mem")),
+		// dead loop
+		Bloc("deadblock",
+			// dead value in dead block
+			Valu("deadval", OpConst, TypeBool, true),
+			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) {
+	fun := Fun("entry",
+		Bloc("entry",
+			Valu("mem", OpArg, TypeMem, ".mem"),
+			Valu("deadval", OpConst, TypeInt64, int64(37)),
+			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) {
+	fun := Fun("entry",
+		Bloc("entry",
+			Valu("cond", OpConst, TypeBool, false),
+			Valu("mem", OpArg, TypeMem, ".mem"),
+			If("cond", "then", "else")),
+		Bloc("then",
+			Goto("exit")),
+		Bloc("else",
+			Goto("exit")),
+		Bloc("exit",
+			Exit("mem")))
+
+	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["then"] {
+			t.Errorf("then block still present")
+		}
+		for _, v := range b.Values {
+			if v == fun.values["cond"] {
+				t.Errorf("constant condition still present")
+			}
+		}
+	}
+
+}