R600: Add failing testcase for <3 x i32> stores.

This is supposed to have the same store size and alignment as <4 x i32>,
but currently is split into a 64-bit and 32-bit store.

llvm-svn: 204729

llvm/test/CodeGen/R600/store-v3i32.ll

@@ -0,0 +1,12 @@
+; XFAIL: *
+; RUN: llc -verify-machineinstrs -march=r600 -mcpu=SI < %s | FileCheck -check-prefix=SI %s
+
+; 3 vectors have the same size and alignment as 4 vectors, so this
+; should be done in a single store.
+
+; SI-LABEL: @store_v3i32:
+; SI: BUFFER_STORE_DWORDX4
+define void @store_v3i32(<3 x i32> addrspace(1)* %out, <3 x i32> %a) nounwind {
+  store <3 x i32> %a, <3 x i32> addrspace(1)* %out, align 16
+  ret void
+}