[AArch64] Fix unintended fallthrough and strengthen cast

This was added in r330630. GCC's -Wimplicit-fallthrough seems to not
fire when the previous case contains a switch itself.

This fallthrough was bening because the helper function implementing the
case used dyn_cast to re-check the type of the node in question. After
fixing the fallthrough, we can strengthen the cast.

llvm-svn: 345864

1 files changed, 4 insertions, 3 deletions

diff --git a/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp b/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
index 3c107016c8b..e6a036e64d8 100644
--- a/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
+++ b/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
@@ -11036,9 +11036,9 @@ static SDValue performNVCASTCombine(SDNode *N) {
 static SDValue performGlobalAddressCombine(SDNode *N, SelectionDAG &DAG,
                                            const AArch64Subtarget *Subtarget,
                                            const TargetMachine &TM) {
-  auto *GN = dyn_cast<GlobalAddressSDNode>(N);
-  if (!GN || Subtarget->ClassifyGlobalReference(GN->getGlobal(), TM) !=
-                 AArch64II::MO_NO_FLAG)
+  auto *GN = cast<GlobalAddressSDNode>(N);
+  if (Subtarget->ClassifyGlobalReference(GN->getGlobal(), TM) !=
+      AArch64II::MO_NO_FLAG)
     return SDValue();
 
   uint64_t MinOffset = -1ull;
@@ -11170,6 +11170,7 @@ SDValue AArch64TargetLowering::PerformDAGCombine(SDNode *N,
     default:
       break;
     }
+    break;
   case ISD::GlobalAddress:
     return performGlobalAddressCombine(N, DAG, Subtarget, getTargetMachine());
   }