add a simple dag combine to replace trivial shl+lshr with
and.  This happens with the store->load narrowing stuff.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@101348 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/CodeGen/ARM/sbfx.ll b/test/CodeGen/ARM/sbfx.ll
index 6f1d87d..d29693e 100644
--- a/test/CodeGen/ARM/sbfx.ll
+++ b/test/CodeGen/ARM/sbfx.ll
@@ -12,7 +12,7 @@
 define i32 @f2(i32 %a) {
 entry:
 ; CHECK: f2:
-; CHECK: ubfx r0, r0, #0, #20
+; CHECK: bfc	r0, #20, #12
     %tmp = shl i32 %a, 12
     %tmp2 = lshr i32 %tmp, 12
     ret i32 %tmp2