1 files changed, 21 insertions, 0 deletions
diff --git a/test/fixedbugs/bug440_64.go b/test/fixedbugs/bug440_64.go
new file mode 100644
index 000000000..3ab3e565d
--- /dev/null
+++ b/test/fixedbugs/bug440_64.go
@@ -0,0 +1,21 @@
+// run
+
+// Test for 6g register move bug.  The optimizer gets confused
+// about 32- vs 64-bit moves during splitContractIndex.
+
+// Issue 3918.
+
+package main
+
+func main() {
+	const c = 0x123400005678
+	index, offset := splitContractIndex(c)
+	if index != (c&0xffffffff)>>5 || offset != c+1 {
+		println("BUG", index, offset)
+	}
+}
+
+func splitContractIndex(ce uint64) (index uint32, offset uint64) {
+	h := uint32(ce)
+	return h >> 5, ce + 1
+}