[polly] r345882 - Fix clang -Wimplicit-fallthrough warnings across llvm, NFC

[Reid Kleckner via llvm-commits]

Author: rnk
Date: Thu Nov  1 12:54:45 2018
New Revision: 345882

URL: http://llvm.org/viewvc/llvm-project?rev=345882&view=rev
Log:
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

Modified:
    polly/trunk/lib/Analysis/ScopBuilder.cpp
    polly/trunk/lib/Analysis/ScopDetection.cpp

Modified: polly/trunk/lib/Analysis/ScopBuilder.cpp
URL: http://llvm.org/viewvc/llvm-project/polly/trunk/lib/Analysis/ScopBuilder.cpp?rev=345882&r1=345881&r2=345882&view=diff
==============================================================================
--- polly/trunk/lib/Analysis/ScopBuilder.cpp (original)
+++ polly/trunk/lib/Analysis/ScopBuilder.cpp Thu Nov  1 12:54:45 2018
@@ -579,7 +579,7 @@ bool ScopBuilder::buildAccessCallInst(Me
     return true;
   case FMRB_OnlyReadsArgumentPointees:
     ReadOnly = true;
-  // Fall through
+    LLVM_FALLTHROUGH;
   case FMRB_OnlyAccessesArgumentPointees: {
     auto AccType = ReadOnly ? MemoryAccess::READ : MemoryAccess::MAY_WRITE;
     Loop *L = LI.getLoopFor(Inst->getParent());
@@ -1216,7 +1216,7 @@ static MemoryAccess::ReductionType getRe
   case Instruction::FAdd:
     if (!BinOp->isFast())
       return MemoryAccess::RT_NONE;
-    // Fall through
+    LLVM_FALLTHROUGH;
   case Instruction::Add:
     return MemoryAccess::RT_ADD;
   case Instruction::Or:
@@ -1228,7 +1228,7 @@ static MemoryAccess::ReductionType getRe
   case Instruction::FMul:
     if (!BinOp->isFast())
       return MemoryAccess::RT_NONE;
-    // Fall through
+    LLVM_FALLTHROUGH;
   case Instruction::Mul:
     if (DisableMultiplicativeReductions)
       return MemoryAccess::RT_NONE;

Modified: polly/trunk/lib/Analysis/ScopDetection.cpp
URL: http://llvm.org/viewvc/llvm-project/polly/trunk/lib/Analysis/ScopDetection.cpp?rev=345882&r1=345881&r2=345882&view=diff
==============================================================================
--- polly/trunk/lib/Analysis/ScopDetection.cpp (original)
+++ polly/trunk/lib/Analysis/ScopDetection.cpp Thu Nov  1 12:54:45 2018
@@ -779,7 +779,7 @@ bool ScopDetection::isValidIntrinsicInst
       if (!isValidAccess(&II, AF, BP, Context))
         return false;
     }
-  // Fall through
+    LLVM_FALLTHROUGH;
   case Intrinsic::memset:
     AF = SE.getSCEVAtScope(cast<MemIntrinsic>(II).getDest(), L);
     if (!AF->isZero()) {