Fix clang -Wimplicit-fallthrough warnings across llvm, NFC

This patch should not introduce any behavior changes. It consists of
mostly one of two changes:
1. Replacing fall through comments with the LLVM_FALLTHROUGH macro
2. Inserting 'break' before falling through into a case block consisting
   of only 'break'.

We were already using this warning with GCC, but its warning behaves
slightly differently. In this patch, the following differences are
relevant:
1. GCC recognizes comments that say "fall through" as annotations, clang
   doesn't
2. GCC doesn't warn on "case N: foo(); default: break;", clang does
3. GCC doesn't warn when the case contains a switch, but falls through
   the outer case.

I will enable the warning separately in a follow-up patch so that it can
be cleanly reverted if necessary.

Reviewers: alexfh, rsmith, lattner, rtrieu, EricWF, bollu

Differential Revision: https://reviews.llvm.org/D53950

llvm-svn: 345882

1 files changed, 1 insertions, 2 deletions

diff --git a/llvm/lib/Target/AMDGPU/SIISelLowering.cpp b/llvm/lib/Target/AMDGPU/SIISelLowering.cpp
index e41cf6e771b..66eb9bbb84c 100644
--- a/llvm/lib/Target/AMDGPU/SIISelLowering.cpp
+++ b/llvm/lib/Target/AMDGPU/SIISelLowering.cpp
@@ -5049,12 +5049,11 @@ SDValue SITargetLowering::LowerINTRINSIC_WO_CHAIN(SDValue Op,
   case Intrinsic::r600_read_tgid_z:
     return getPreloadedValue(DAG, *MFI, VT,
                              AMDGPUFunctionArgInfo::WORKGROUP_ID_Z);
-  case Intrinsic::amdgcn_workitem_id_x: {
+  case Intrinsic::amdgcn_workitem_id_x:
   case Intrinsic::r600_read_tidig_x:
     return loadInputValue(DAG, &AMDGPU::VGPR_32RegClass, MVT::i32,
                           SDLoc(DAG.getEntryNode()),
                           MFI->getArgInfo().WorkItemIDX);
-  }
   case Intrinsic::amdgcn_workitem_id_y:
   case Intrinsic::r600_read_tidig_y:
     return loadInputValue(DAG, &AMDGPU::VGPR_32RegClass, MVT::i32,