Canonicalize (srl (bswap x), 16) to (rotr (bswap x), 16) if the high 16 bits
of x are zero. This optimizes rev + lsr 16 to rev16.

rdar://10750814


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151230 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/CodeGen/ARM/rev.ll b/test/CodeGen/ARM/rev.ll
index ea44c28..6bb6743 100644
--- a/test/CodeGen/ARM/rev.ll
+++ b/test/CodeGen/ARM/rev.ll
@@ -112,11 +112,11 @@
   ret i32 %conv3
 }
 
+; rdar://10750814
 define zeroext i16 @test9(i16 zeroext %v) nounwind readnone {
 entry:
 ; CHECK: test9
-; CHECK: rev r0, r0
-; CHECK: lsr r0, r0, #16
+; CHECK: rev16 r0, r0
   %conv = zext i16 %v to i32
   %shr4 = lshr i32 %conv, 8
   %shl = shl nuw nsw i32 %conv, 8