commit 4dc0b1ac60f947c23bbb0e20a7efb636c214b0a8
author Reid Kleckner <rnk@google.com> Thu Nov 01 19:54:45 2018 +0000
committer Reid Kleckner <rnk@google.com> Thu Nov 01 19:54:45 2018 +0000
tree be694515ce144c8d6ab1d1031b1f44817faac9ae
parent de4f7747837cbd9db9cb393c05283964fbc4a985

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

clang/lib/CodeGen/CGBuiltin.cpp

diff --git a/clang/lib/CodeGen/CGBuiltin.cpp b/clang/lib/CodeGen/CGBuiltin.cpp
index bf53e25..2c7a3d7 100644
--- a/clang/lib/CodeGen/CGBuiltin.cpp
+++ b/clang/lib/CodeGen/CGBuiltin.cpp
@@ -6867,7 +6867,7 @@
   case NEON::BI__builtin_neon_vcvth_f16_u32:
   case NEON::BI__builtin_neon_vcvth_f16_u64:
     usgn = true;
-    // FALL THROUGH
+    LLVM_FALLTHROUGH;
   case NEON::BI__builtin_neon_vcvth_f16_s16:
   case NEON::BI__builtin_neon_vcvth_f16_s32:
   case NEON::BI__builtin_neon_vcvth_f16_s64: {
@@ -6887,7 +6887,7 @@
   }
   case NEON::BI__builtin_neon_vcvth_u16_f16:
     usgn = true;
-    // FALL THROUGH
+    LLVM_FALLTHROUGH;
   case NEON::BI__builtin_neon_vcvth_s16_f16: {
     Ops.push_back(EmitScalarExpr(E->getArg(0)));
     Ops[0] = Builder.CreateBitCast(Ops[0], HalfTy);
@@ -6897,7 +6897,7 @@
   }
   case NEON::BI__builtin_neon_vcvth_u32_f16:
     usgn = true;
-    // FALL THROUGH
+    LLVM_FALLTHROUGH;
   case NEON::BI__builtin_neon_vcvth_s32_f16: {
     Ops.push_back(EmitScalarExpr(E->getArg(0)));
     Ops[0] = Builder.CreateBitCast(Ops[0], HalfTy);
@@ -6907,7 +6907,7 @@
   }
   case NEON::BI__builtin_neon_vcvth_u64_f16:
     usgn = true;
-    // FALL THROUGH
+    LLVM_FALLTHROUGH;
   case NEON::BI__builtin_neon_vcvth_s64_f16: {
     Ops.push_back(EmitScalarExpr(E->getArg(0)));
     Ops[0] = Builder.CreateBitCast(Ops[0], HalfTy);