1 files changed, 62 insertions, 0 deletions
diff --git a/test/fixedbugs/issue21655.go b/test/fixedbugs/issue21655.go
new file mode 100644
index 0000000..66d4e3a
--- /dev/null
+++ b/test/fixedbugs/issue21655.go
@@ -0,0 +1,62 @@
+// compile
+
+// 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.
+
+// Make sure assembly offsets don't get too large.
+
+// To trigger issue21655, the index offset needs to be small
+// enough to fit into an int32 (to get rewritten to an ADDQconst)
+// but large enough to overflow an int32 after multiplying by the stride.
+
+package main
+
+func f1(a []int64, i int64) int64 {
+	return a[i+1<<30]
+}
+func f2(a []int32, i int64) int32 {
+	return a[i+1<<30]
+}
+func f3(a []int16, i int64) int16 {
+	return a[i+1<<30]
+}
+func f4(a []int8, i int64) int8 {
+	return a[i+1<<31]
+}
+func f5(a []float64, i int64) float64 {
+	return a[i+1<<30]
+}
+func f6(a []float32, i int64) float32 {
+	return a[i+1<<30]
+}
+
+// Note: Before the fix for issue 21655, f{1,2,5,6} made
+// the compiler crash. f3 silently generated the wrong
+// code, using an offset of -1<<31 instead of 1<<31.
+// (This is due to the assembler accepting offsets
+// like 0x80000000 and silently using them as
+// signed 32 bit offsets.)
+// f4 was ok, but testing it can't hurt.
+
+func f7(ss []*string, i int) string {
+	const offset = 3 << 29 // 3<<29 * 4 = 3<<31 = 1<<31 mod 1<<32.
+	if i > offset {
+		return *ss[i-offset]
+	}
+	return ""
+}
+func f8(ss []*string, i int) string {
+	const offset = 3<<29 + 10
+	if i > offset {
+		return *ss[i-offset]
+	}
+	return ""
+}
+func f9(ss []*string, i int) string {
+	const offset = 3<<29 - 10
+	if i > offset {
+		return *ss[i-offset]
+	}
+	return ""
+}