[dev.ssa] cmd/compile: add test to detect cse bug

Adds a test to detect the bug that slipped in earlier when partioning
by the Aux value, but not sorting by it.

Change-Id: I56d0ba76383bbc1514b3dabd295e369771c26645
Reviewed-on: https://go-review.googlesource.com/19382
Run-TryBot: Todd Neal <todd@tneal.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>

src/cmd/compile/internal/ssa/cse_test.go

+// Copyright 2016 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"
+
+// This tests for a bug found when partitioning, but not sorting by the Aux value.
+func TestCSEAuxPartitionBug(t *testing.T) {
+	c := testConfig(t)
+	arg1Aux := "arg1-aux"
+	arg2Aux := "arg2-aux"
+	arg3Aux := "arg3-aux"
+
+	// construct lots of values with args that have aux values and place
+	// them in an order that triggers the bug
+	fun := Fun(c, "entry",
+		Bloc("entry",
+			Valu("start", OpInitMem, TypeMem, 0, nil),
+			Valu("sp", OpSP, TypeBytePtr, 0, nil),
+			Valu("r7", OpAdd64, TypeInt64, 0, nil, "arg3", "arg1"),
+			Valu("r1", OpAdd64, TypeInt64, 0, nil, "arg1", "arg2"),
+			Valu("arg1", OpArg, TypeInt64, 0, arg1Aux),
+			Valu("arg2", OpArg, TypeInt64, 0, arg2Aux),
+			Valu("arg3", OpArg, TypeInt64, 0, arg3Aux),
+			Valu("r9", OpAdd64, TypeInt64, 0, nil, "r7", "r8"),
+			Valu("r4", OpAdd64, TypeInt64, 0, nil, "r1", "r2"),
+			Valu("r8", OpAdd64, TypeInt64, 0, nil, "arg3", "arg2"),
+			Valu("r2", OpAdd64, TypeInt64, 0, nil, "arg1", "arg2"),
+			Valu("raddr", OpAddr, TypeInt64Ptr, 0, nil, "sp"),
+			Valu("raddrdef", OpVarDef, TypeMem, 0, nil, "start"),
+			Valu("r6", OpAdd64, TypeInt64, 0, nil, "r4", "r5"),
+			Valu("r3", OpAdd64, TypeInt64, 0, nil, "arg1", "arg2"),
+			Valu("r5", OpAdd64, TypeInt64, 0, nil, "r2", "r3"),
+			Valu("r10", OpAdd64, TypeInt64, 0, nil, "r6", "r9"),
+			Valu("rstore", OpStore, TypeMem, 8, nil, "raddr", "r10", "raddrdef"),
+			Goto("exit")),
+		Bloc("exit",
+			Exit("rstore")))
+
+	CheckFunc(fun.f)
+	cse(fun.f)
+	deadcode(fun.f)
+	CheckFunc(fun.f)
+
+	s1Cnt := 2
+	// r1 == r2 == r3, needs to remove two of this set
+	s2Cnt := 1
+	// r4 == r5, needs to remove one of these
+	for k, v := range fun.values {
+		if v.Op == OpInvalid {
+			switch k {
+			case "r1":
+				fallthrough
+			case "r2":
+				fallthrough
+			case "r3":
+				if s1Cnt == 0 {
+					t.Errorf("cse removed all of r1,r2,r3")
+				}
+				s1Cnt--
+
+			case "r4":
+				fallthrough
+			case "r5":
+				if s2Cnt == 0 {
+					t.Errorf("cse removed all of r4,r5")
+				}
+				s2Cnt--
+			default:
+				t.Errorf("cse removed %s, but shouldn't have", k)
+			}
+		}
+	}
+
+	if s1Cnt != 0 || s2Cnt != 0 {
+		t.Errorf("%d values missed during cse", s1Cnt+s2Cnt)
+	}
+
+}

src/cmd/compile/internal/ssa/type_test.go

@@ -73,4 +73,5 @@ var (
 	TypeUInt64     = &TypeImpl{Size_: 8, Align: 8, Integer: true, Name: "uint64"}
 	TypeBool       = &TypeImpl{Size_: 1, Align: 1, Boolean: true, Name: "bool"}
 	TypeBytePtr    = &TypeImpl{Size_: 8, Align: 8, Ptr: true, Name: "*byte"}
+	TypeInt64Ptr   = &TypeImpl{Size_: 8, Align: 8, Ptr: true, Name: "*int64"}
 )