--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/CodeGen/X86/shuffle-combine-crash.ll	Mon Sep 08 22:06:00 2014 +0900
@@ -0,0 +1,30 @@
+; RUN: llc < %s -mtriple=x86_64-unknown-linux-gnu -mcpu=corei7 
+
+; Verify that DAGCombiner does not crash when checking if it is
+; safe to fold the shuffles in function @sample_test according to rule
+;  (shuffle (shuffle A, Undef, M0), Undef, M1) -> (shuffle A, Undef, M2)
+;
+; The DAGCombiner avoids folding shuffles if
+; the resulting shuffle dag node is not legal for the target.
+; That means, the shuffle must have legal type and legal mask.
+;
+; Before, the DAGCombiner forgot to check if the resulting shuffle
+; was legal. It instead just called method
+; 'X86TargetLowering::isShuffleMaskLegal'; however, that was not enough since
+; that method always expect to have a valid vector type in input.
+; As a consequence, compiling the function below would have caused a crash.
+
+define void @sample_test() {
+  br i1 undef, label %5, label %1
+
+; <label>:1                                       ; preds = %0
+  %2 = load <4 x i8>* undef
+  %3 = shufflevector <4 x i8> %2, <4 x i8> undef, <4 x i32> <i32 2, i32 2, i32 0, i32 0>
+  %4 = shufflevector <4 x i8> %3, <4 x i8> undef, <4 x i32> <i32 2, i32 3, i32 0, i32 1>
+  store <4 x i8> %4, <4 x i8>* undef
+  br label %5
+
+; <label>:5                                       ; preds = %1, %0
+  ret void
+}
+