1 files changed, 181 insertions, 0 deletions
diff --git a/test/checkbce.go b/test/checkbce.go
new file mode 100644
index 0000000..6a12609
--- /dev/null
+++ b/test/checkbce.go
@@ -0,0 +1,181 @@
+// +build amd64,!gcflags_noopt
+// errorcheck -0 -d=ssa/check_bce/debug=3
+
+// 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.
+
+// Test that the compiler does bounds check elimination as expected.
+// This avoids accidental regressions.
+
+package main
+
+import "encoding/binary"
+
+func f0(a []int) {
+	a[0] = 1 // ERROR "Found IsInBounds$"
+	a[0] = 1
+	a[6] = 1 // ERROR "Found IsInBounds$"
+	a[6] = 1
+	a[5] = 1
+	a[5] = 1
+}
+
+func f1(a [256]int, i int) {
+	var j int
+	useInt(a[i]) // ERROR "Found IsInBounds$"
+	j = i % 256
+	useInt(a[j]) // ERROR "Found IsInBounds$"
+	j = i & 255
+	useInt(a[j])
+	j = i & 17
+	useInt(a[j])
+
+	if 4 <= i && i < len(a) {
+		useInt(a[i])
+		useInt(a[i-1])
+		useInt(a[i-4])
+	}
+}
+
+func f2(a [256]int, i uint) {
+	useInt(a[i]) // ERROR "Found IsInBounds$"
+	j := i % 256
+	useInt(a[j])
+	j = i & 255
+	useInt(a[j])
+	j = i & 17
+	useInt(a[j])
+}
+
+func f2a(a [35]int, i uint8) {
+	useInt(a[i]) // ERROR "Found IsInBounds$"
+	j := i & 34
+	useInt(a[j])
+	j = i & 17
+	useInt(a[j])
+}
+
+func f2b(a [35]int, i uint16) {
+	useInt(a[i]) // ERROR "Found IsInBounds$"
+	j := i & 34
+	useInt(a[j])
+	j = i & 17
+	useInt(a[j])
+}
+
+func f2c(a [35]int, i uint32) {
+	useInt(a[i]) // ERROR "Found IsInBounds$"
+	j := i & 34
+	useInt(a[j])
+	j = i & 17
+	useInt(a[j])
+}
+
+func f3(a [256]int, i uint8) {
+	useInt(a[i])
+	useInt(a[i+10])
+	useInt(a[i+14])
+}
+
+func f4(a [27]int, i uint8) {
+	useInt(a[i%15])
+	useInt(a[i%19])
+	useInt(a[i%27])
+}
+
+func f5(a []int) {
+	if len(a) > 5 {
+		useInt(a[5])
+		useSlice(a[6:])
+		useSlice(a[:6])
+	}
+}
+
+func f6(a [32]int, b [64]int, i int) {
+	useInt(a[uint32(i*0x07C4ACDD)>>27])
+	useInt(b[uint64(i*0x07C4ACDD)>>58])
+	useInt(a[uint(i*0x07C4ACDD)>>59])
+
+	// The following bounds should not be removed because they can overflow.
+	useInt(a[uint32(i*0x106297f105d0cc86)>>26]) // ERROR "Found IsInBounds$"
+	useInt(b[uint64(i*0x106297f105d0cc86)>>57]) // ERROR "Found IsInBounds$"
+	useInt(a[int32(i*0x106297f105d0cc86)>>26])  // ERROR "Found IsInBounds$"
+	useInt(b[int64(i*0x106297f105d0cc86)>>57])  // ERROR "Found IsInBounds$"
+}
+
+func g1(a []int) {
+	for i := range a {
+		a[i] = i
+		useSlice(a[:i+1])
+		useSlice(a[:i])
+	}
+}
+
+func g2(a []int) {
+	useInt(a[3]) // ERROR "Found IsInBounds$"
+	useInt(a[2])
+	useInt(a[1])
+	useInt(a[0])
+}
+
+func g3(a []int) {
+	for i := range a[:256] { // ERROR "Found IsSliceInBounds$"
+		useInt(a[i]) // ERROR "Found IsInBounds$"
+	}
+	b := a[:256]
+	for i := range b {
+		useInt(b[i])
+	}
+}
+
+func g4(a [100]int) {
+	for i := 10; i < 50; i++ {
+		useInt(a[i-10])
+		useInt(a[i])
+		useInt(a[i+25])
+		useInt(a[i+50])
+
+		// The following are out of bounds.
+		useInt(a[i-11]) // ERROR "Found IsInBounds$"
+		useInt(a[i+51]) // ERROR "Found IsInBounds$"
+	}
+}
+
+func decode1(data []byte) (x uint64) {
+	for len(data) >= 32 {
+		x += binary.BigEndian.Uint64(data[:8])
+		x += binary.BigEndian.Uint64(data[8:16])
+		x += binary.BigEndian.Uint64(data[16:24])
+		x += binary.BigEndian.Uint64(data[24:32])
+		data = data[32:]
+	}
+	return x
+}
+
+func decode2(data []byte) (x uint64) {
+	// TODO(rasky): this should behave like decode1 and compile to no
+	// boundchecks. We're currently not able to remove all of them.
+	for len(data) >= 32 {
+		x += binary.BigEndian.Uint64(data)
+		data = data[8:]
+		x += binary.BigEndian.Uint64(data) // ERROR "Found IsInBounds$"
+		data = data[8:]
+		x += binary.BigEndian.Uint64(data) // ERROR "Found IsInBounds$"
+		data = data[8:]
+		x += binary.BigEndian.Uint64(data) // ERROR "Found IsInBounds$"
+		data = data[8:]
+	}
+	return x
+}
+
+//go:noinline
+func useInt(a int) {
+}
+
+//go:noinline
+func useSlice(a []int) {
+}
+
+func main() {
+}