Replace "fallthrough" comments with LLVM_FALLTHROUGH

This is a mechanical change of comments in switches like fallthrough,
fall-through, or fall-thru to use the LLVM_FALLTHROUGH macro instead.

llvm-svn: 278902
diff --git a/llvm/lib/Analysis/InstructionSimplify.cpp b/llvm/lib/Analysis/InstructionSimplify.cpp
index 3a1b272..f79cfad 100644
--- a/llvm/lib/Analysis/InstructionSimplify.cpp
+++ b/llvm/lib/Analysis/InstructionSimplify.cpp
@@ -2773,7 +2773,7 @@
                      Q.CxtI, Q.DT);
       if (!KnownNonNegative)
         break;
-      // fall-through
+      LLVM_FALLTHROUGH;
     case ICmpInst::ICMP_EQ:
     case ICmpInst::ICMP_UGT:
     case ICmpInst::ICMP_UGE:
@@ -2784,7 +2784,7 @@
                      Q.CxtI, Q.DT);
       if (!KnownNonNegative)
         break;
-      // fall-through
+      LLVM_FALLTHROUGH;
     case ICmpInst::ICMP_NE:
     case ICmpInst::ICMP_ULT:
     case ICmpInst::ICMP_ULE:
@@ -2804,7 +2804,7 @@
                      Q.CxtI, Q.DT);
       if (!KnownNonNegative)
         break;
-      // fall-through
+      LLVM_FALLTHROUGH;
     case ICmpInst::ICMP_NE:
     case ICmpInst::ICMP_UGT:
     case ICmpInst::ICMP_UGE:
@@ -2815,7 +2815,7 @@
                      Q.CxtI, Q.DT);
       if (!KnownNonNegative)
         break;
-      // fall-through
+      LLVM_FALLTHROUGH;
     case ICmpInst::ICMP_EQ:
     case ICmpInst::ICMP_ULT:
     case ICmpInst::ICMP_ULE:
@@ -2877,7 +2877,7 @@
     case Instruction::LShr:
       if (ICmpInst::isSigned(Pred))
         break;
-      // fall-through
+      LLVM_FALLTHROUGH;
     case Instruction::SDiv:
     case Instruction::AShr:
       if (!LBO->isExact() || !RBO->isExact())