1 files changed, 96 insertions, 0 deletions
diff --git a/src/cmd/compile/internal/test/align_test.go b/src/cmd/compile/internal/test/align_test.go
new file mode 100644
index 0000000..32afc92
--- /dev/null
+++ b/src/cmd/compile/internal/test/align_test.go
@@ -0,0 +1,96 @@
+// Copyright 2021 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 to make sure that equality functions (and hash
+// functions) don't do unaligned reads on architectures
+// that can't do unaligned reads. See issue 46283.
+
+package test
+
+import "testing"
+
+type T1 struct {
+	x          float32
+	a, b, c, d int16 // memequal64
+}
+type T2 struct {
+	x          float32
+	a, b, c, d int32 // memequal128
+}
+
+type A2 [2]byte // eq uses a 2-byte load
+type A4 [4]byte // eq uses a 4-byte load
+type A8 [8]byte // eq uses an 8-byte load
+
+//go:noinline
+func cmpT1(p, q *T1) {
+	if *p != *q {
+		panic("comparison test wrong")
+	}
+}
+
+//go:noinline
+func cmpT2(p, q *T2) {
+	if *p != *q {
+		panic("comparison test wrong")
+	}
+}
+
+//go:noinline
+func cmpA2(p, q *A2) {
+	if *p != *q {
+		panic("comparison test wrong")
+	}
+}
+
+//go:noinline
+func cmpA4(p, q *A4) {
+	if *p != *q {
+		panic("comparison test wrong")
+	}
+}
+
+//go:noinline
+func cmpA8(p, q *A8) {
+	if *p != *q {
+		panic("comparison test wrong")
+	}
+}
+
+func TestAlignEqual(t *testing.T) {
+	cmpT1(&T1{}, &T1{})
+	cmpT2(&T2{}, &T2{})
+
+	m1 := map[T1]bool{}
+	m1[T1{}] = true
+	m1[T1{}] = false
+	if len(m1) != 1 {
+		t.Fatalf("len(m1)=%d, want 1", len(m1))
+	}
+	m2 := map[T2]bool{}
+	m2[T2{}] = true
+	m2[T2{}] = false
+	if len(m2) != 1 {
+		t.Fatalf("len(m2)=%d, want 1", len(m2))
+	}
+
+	type X2 struct {
+		y byte
+		z A2
+	}
+	var x2 X2
+	cmpA2(&x2.z, &A2{})
+	type X4 struct {
+		y byte
+		z A4
+	}
+	var x4 X4
+	cmpA4(&x4.z, &A4{})
+	type X8 struct {
+		y byte
+		z A8
+	}
+	var x8 X8
+	cmpA8(&x8.z, &A8{})
+}