--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/CodeGen/Hexagon/tail-dup-subreg-abort.ll	Tue Jan 26 22:53:40 2016 +0900
@@ -0,0 +1,28 @@
+; RUN: llc -march=hexagon -O2 -disable-cgp < %s
+; REQUIRES: asserts
+;
+; Tail duplication can ignore subregister information on PHI nodes, and as
+; a result, generate COPY instructions between registers of different classes.
+; This could lead to HexagonInstrInfo::copyPhysReg aborting on an unhandled
+; src/dst combination.
+;
+define i32 @foo(i32 %x, i64 %y) nounwind {
+entry:
+  %a = icmp slt i32 %x, 0
+  %lo = trunc i64 %y to i32
+  br i1 %a, label %next, label %tail
+tail:
+  br label %join
+next:
+  %c = icmp eq i32 %x, 0
+  br i1 %c, label %b1, label %tail
+b1:
+  %t1 = lshr i64 %y, 32
+  %hi = trunc i64 %t1 to i32
+  br label %join
+join:
+  %val = phi i32 [ %hi, %b1 ], [ %lo, %tail ]
+  ret i32 %val
+}
+
+