--- gcc/gcc/alias.c
+++ gcc/gcc/alias.c
@@ -1398,7 +1398,7 @@ find_base_value (rtx src)
       if (GET_CODE (src) != PLUS && GET_CODE (src) != MINUS)
 	break;
 
-      /* ... fall through ...  */
+      /* fall through */
 
     case PLUS:
     case MINUS:
--- gcc/gcc/c-family/c-common.c
+++ gcc/gcc/c-family/c-common.c
@@ -12709,7 +12712,7 @@ scalar_to_vector (location_t loc, enum tree_code code, tree op0, tree op1,
       case BIT_XOR_EXPR:
       case BIT_AND_EXPR:
 	integer_only_op = true;
-	/* ... fall through ...  */
+	/* fall through */
 
       case VEC_COND_EXPR:
 
--- gcc/gcc/c-family/c-opts.c
+++ gcc/gcc/c-family/c-opts.c
@@ -439,7 +439,7 @@ c_common_handle_option (size_t scode, const char *arg, int value,
 
     case OPT_ffreestanding:
       value = !value;
-      /* Fall through....  */
+      /* Fall through.  */
     case OPT_fhosted:
       flag_hosted = value;
       flag_no_builtin = !value;
--- gcc/gcc/c-family/c-pragma.c
+++ gcc/gcc/c-family/c-pragma.c
@@ -214,6 +214,7 @@ handle_pragma_pack (cpp_reader * ARG_UNUSED (dummy))
 	    align = maximum_field_alignment;
 	    break;
 	  }
+	/* FALLTHRU */
       default:
 	GCC_BAD2 ("alignment must be a small power of two, not %d", align);
       }
--- gcc/gcc/c-family/c-pretty-print.c
+++ gcc/gcc/c-family/c-pretty-print.c
@@ -1662,7 +1662,7 @@ c_pretty_printer::postfix_expression (tree e)
           id_expression (TREE_OPERAND (e, 0));
 	  break;
 	}
-      /* else fall through.  */
+      /* fall through.  */
 
     default:
       primary_expression (e);
--- gcc/gcc/c-family/cilk.c
+++ gcc/gcc/c-family/cilk.c
@@ -1097,6 +1097,7 @@ extract_free_variables (tree t, struct wrapper_data *wd,
     case RESULT_DECL:
       if (wd->type != CILK_BLOCK_SPAWN)
 	TREE_ADDRESSABLE (t) = 1;
+      /* FALLTHRU */
     case VAR_DECL:
     case PARM_DECL:
       if (!is_global_var (t))
--- gcc/gcc/c/c-parser.c
+++ gcc/gcc/c/c-parser.c
@@ -1557,6 +1557,7 @@ c_parser_external_declaration (c_parser *parser)
 	}
       /* Else fall through, and yield a syntax error trying to parse
 	 as a declaration or function definition.  */
+      /* FALLTHRU */
     default:
     decl_or_fndef:
       /* A declaration or a function definition (or, in Objective-C,
@@ -8174,6 +8175,7 @@ c_parser_postfix_expression (c_parser *parser)
 	  break;
 	}
       /* Else fall through to report error.  */
+      /* FALLTHRU */
     default:
       c_parser_error (parser, "expected expression");
       expr.set_error ();
--- gcc/gcc/c/c-typeck.c
+++ gcc/gcc/c/c-typeck.c
@@ -4493,7 +4493,7 @@ build_unary_op (location_t location,
 	      return error_mark_node;
 	    }
 
-	  /* ... fall through ...  */
+	  /* fall through */
 
 	case ARRAY_REF:
 	  if (TYPE_REVERSE_STORAGE_ORDER (TREE_TYPE (TREE_OPERAND (arg, 0))))
@@ -4695,10 +4695,10 @@ c_mark_addressable (tree exp)
 	    return false;
 	  }
 
-	/* drops in */
+	/* FALLTHRU */
       case FUNCTION_DECL:
 	TREE_ADDRESSABLE (x) = 1;
-	/* drops out */
+	/* FALLTHRU */
       default:
 	return true;
     }
--- gcc/gcc/cfgexpand.c
+++ gcc/gcc/cfgexpand.c
@@ -4239,7 +4239,7 @@ expand_debug_expr (tree exp)
 	  set_mem_attributes (op0, exp, 0);
 	  return op0;
 	}
-      /* Fall through...  */
+      /* Fall through.  */
 
     case INTEGER_CST:
     case REAL_CST:
--- gcc/gcc/combine.c
+++ gcc/gcc/combine.c
@@ -5135,7 +5135,7 @@ find_split_point (rtx *loc, rtx_insn *insn, bool set_src)
       split = find_split_point (&XEXP (x, 2), insn, false);
       if (split)
 	return split;
-      /* ... fall through ...  */
+      /* fall through */
     case RTX_BIN_ARITH:
     case RTX_COMM_ARITH:
     case RTX_COMPARE:
@@ -5143,7 +5143,7 @@ find_split_point (rtx *loc, rtx_insn *insn, bool set_src)
       split = find_split_point (&XEXP (x, 1), insn, false);
       if (split)
 	return split;
-      /* ... fall through ...  */
+      /* fall through */
     case RTX_UNARY:
       /* Some machines have (and (shift ...) ...) insns.  If X is not
 	 an AND, but XEXP (X, 0) is, use it as our split point.  */
@@ -6955,6 +6955,7 @@ expand_compound_operation (rtx x)
     {
     case ZERO_EXTEND:
       unsignedp = 1;
+      /* FALLTHRU */
     case SIGN_EXTEND:
       /* We can't necessarily use a const_int for a multiword mode;
 	 it depends on implicitly extending the value.
@@ -6997,7 +6998,7 @@ expand_compound_operation (rtx x)
     case ZERO_EXTRACT:
       unsignedp = 1;
 
-      /* ... fall through ...  */
+      /* fall through */
 
     case SIGN_EXTRACT:
       /* If the operand is a CLOBBER, just return it.  */
@@ -8037,7 +8038,7 @@ make_compound_operation (rtx x, enum rtx_code in_code)
 	  break;
 	}
 
-      /* ... fall through ...  */
+      /* fall through */
 
     case ASHIFTRT:
       lhs = XEXP (x, 0);
@@ -8265,6 +8266,7 @@ canon_reg_for_combine (rtx x, rtx reg)
       if (op0 != XEXP (x, 0) || op1 != XEXP (x, 1) || op2 != XEXP (x, 2))
 	return simplify_gen_ternary (GET_CODE (x), GET_MODE (x),
 				     GET_MODE (op0), op0, op1, op2);
+      /* FALLTHRU */
 
     case RTX_OBJ:
       if (REG_P (x))
@@ -8531,7 +8533,7 @@ force_to_mode (rtx x, machine_mode mode, unsigned HOST_WIDE_INT mask,
 				mode, smask, next_select);
       }
 
-      /* ... fall through ...  */
+      /* fall through */
 
     case MULT:
       /* Substituting into the operands of a widening MULT is not likely to
@@ -10404,7 +10406,7 @@ simplify_shift_const_1 (enum rtx_code code, machine_mode result_mode,
 	      continue;
 	    }
 
-	  /* ... fall through ...  */
+	  /* fall through */
 
 	case LSHIFTRT:
 	case ASHIFT:
@@ -11730,7 +11732,7 @@ simplify_comparison (enum rtx_code code, rtx *pop0, rtx *pop1)
 	      continue;
 	    }
 
-	  /* ... fall through ...  */
+	  /* fall through */
 
 	case SIGN_EXTRACT:
 	  tem = expand_compound_operation (op0);
--- gcc/gcc/config/aarch64/aarch64-builtins.c
+++ gcc/gcc/config/aarch64/aarch64-builtins.c
@@ -1017,6 +1017,7 @@ aarch64_simd_expand_args (rtx target, int icode, int have_retval,
 		}
 	      /* Fall through - if the lane index isn't a constant then
 		 the next case will error.  */
+	      /* FALLTHRU */
 	    case SIMD_ARG_CONSTANT:
 constant_arg:
 	      if (!(*insn_data[icode].operand[opc].predicate)
--- gcc/gcc/config/aarch64/predicates.md
+++ gcc/gcc/config/aarch64/predicates.md
@@ -180,6 +180,7 @@
 	  || GET_CODE (XEXP (op, 1)) != CONST_INT)
 	return false;
       op = XEXP (op, 0);
+      /* FALLTHRU */
 
     case SYMBOL_REF:
       return SYMBOL_REF_TLS_MODEL (op) == TLS_MODEL_INITIAL_EXEC;
@@ -201,6 +202,7 @@
 	  || GET_CODE (XEXP (op, 1)) != CONST_INT)
 	return false;
       op = XEXP (op, 0);
+      /* FALLTHRU */
 
     case SYMBOL_REF:
       return SYMBOL_REF_TLS_MODEL (op) == TLS_MODEL_LOCAL_EXEC;
--- gcc/gcc/config/i386/i386.c
+++ gcc/gcc/config/i386/i386.c
@@ -9321,6 +9321,7 @@ pass_in_reg:
 	error_p = 1;
       if (cum->float_in_sse < 2)
 	break;
+      /* FALLTHRU */
     case SFmode:
       if (cum->float_in_sse == -1)
 	error_p = 1;
@@ -9588,6 +9589,7 @@ pass_in_reg:
 	error_p = 1;
       if (cum->float_in_sse < 2)
 	break;
+      /* FALLTHRU */
     case SFmode:
       if (cum->float_in_sse == -1)
 	error_p = 1;
@@ -10993,6 +10995,7 @@ ix86_gimplify_va_arg (tree valist, tree type, gimple_seq *pre_p,
 	  container = NULL;
 	  break;
 	}
+      /* FALLTHRU */
 
     default:
       container = construct_container (nat_mode, TYPE_MODE (type),
@@ -17301,6 +17304,7 @@ print_reg (rtx x, int code, FILE *file)
     case 4:
       if (LEGACY_INT_REGNO_P (regno))
 	putc (msize == 8 && TARGET_64BIT ? 'r' : 'e', file);
+      /* FALLTHRU */
     case 16:
     case 12:
     case 2:
@@ -17710,6 +17714,7 @@ ix86_print_operand (FILE *file, rtx x, int code)
 		  fputs ("eq_us", file);
 		  break;
 		}
+	     /* FALLTHRU */
 	    case EQ:
 	      fputs ("eq", file);
 	      break;
@@ -17719,6 +17724,7 @@ ix86_print_operand (FILE *file, rtx x, int code)
 		  fputs ("nge", file);
 		  break;
 		}
+	     /* FALLTHRU */
 	    case LT:
 	      fputs ("lt", file);
 	      break;
@@ -17728,6 +17734,7 @@ ix86_print_operand (FILE *file, rtx x, int code)
 		  fputs ("ngt", file);
 		  break;
 		}
+	     /* FALLTHRU */
 	    case LE:
 	      fputs ("le", file);
 	      break;
@@ -17740,6 +17747,7 @@ ix86_print_operand (FILE *file, rtx x, int code)
 		  fputs ("neq_oq", file);
 		  break;
 		}
+	     /* FALLTHRU */
 	    case NE:
 	      fputs ("neq", file);
 	      break;
@@ -17749,6 +17757,7 @@ ix86_print_operand (FILE *file, rtx x, int code)
 		  fputs ("ge", file);
 		  break;
 		}
+	     /* FALLTHRU */
 	    case UNGE:
 	      fputs ("nlt", file);
 	      break;
@@ -17758,6 +17767,7 @@ ix86_print_operand (FILE *file, rtx x, int code)
 		  fputs ("gt", file);
 		  break;
 		}
+	     /* FALLTHRU */
 	    case UNGT:
 	      fputs ("nle", file);
 	      break;
@@ -21505,6 +21515,7 @@ ix86_build_const_vector (machine_mode mode, bool vect, rtx value)
     case V4DImode:
     case V2DImode:
       gcc_assert (vect);
+      /* FALLTHRU */
     case V16SFmode:
     case V8SFmode:
     case V4SFmode:
@@ -22490,6 +22501,7 @@ ix86_expand_branch (enum rtx_code code, rtx op0, rtx op1, rtx label)
 	  op0 = force_reg (mode, gen_rtx_XOR (mode, op0, op1));
 	  op1 = const0_rtx;
 	}
+      /* FALLTHRU */
     case TImode:
       /* Expand DImode branch into multiple compare+branch.  */
       {
@@ -29851,7 +29863,7 @@ ix86_sched_init_global (FILE *, int, int)
 	  core2i7_ifetch_block_max_insns = 6;
 	  break;
 	}
-      /* ... Fall through ...  */
+      /* Fall through.  */
     default:
       targetm.sched.dfa_post_advance_cycle = NULL;
       targetm.sched.first_cycle_multipass_init = NULL;
@@ -40122,6 +40134,7 @@ ix86_expand_args_builtin (const struct builtin_description *d,
 			error ("the next to last argument must be an 8-bit immediate");
 			break;
 		      }
+		    /* FALLTHRU */
 		  case 1:
 		    error ("the last argument must be an 8-bit immediate");
 		    break;
@@ -42853,6 +42866,7 @@ rdseed_step:
 	  if (!TARGET_SSE)
 	    /* Emit a normal call if SSE isn't available.  */
 	    return expand_call (exp, target, ignore);
+	  /* FALLTHRU */
 	default:
 	  return ix86_expand_args_builtin (d, exp, target);
 	}
@@ -47006,6 +47020,7 @@ ix86_expand_vector_init_one_var (bool mmx_ok, machine_mode mode,
       /* Use ix86_expand_vector_set in 64bit mode only.  */
       if (!TARGET_64BIT)
 	return false;
+      /* FALLTHRU */
     case V4DFmode:
     case V8SFmode:
     case V8SImode:
--- gcc/gcc/config/rs6000/rs6000.c
+++ gcc/gcc/config/rs6000/rs6000.c
@@ -22949,6 +22949,7 @@ rs6000_emit_vector_compare_inner (enum rtx_code code, rtx op0, rtx op1)
     case GE:
       if (GET_MODE_CLASS (mode) == MODE_VECTOR_INT)
 	return NULL_RTX;
+      /* FALLTHRU */
 
     case EQ:
     case GT:
@@ -30687,6 +30688,7 @@ rs6000_adjust_cost (rtx_insn *insn, int dep_type, rtx_insn *dep_insn, int cost,
             }
         }
       /* Fall through, no cost for output dependency.  */
+      /* FALLTHRU */
 
     case REG_DEP_ANTI:
       /* Anti dependency; DEP_INSN reads a register that INSN writes some
@@ -31833,6 +31835,7 @@ insn_must_be_first_in_group (rtx_insn *insn)
     case PROCESSOR_POWER5:
       if (is_cracked_insn (insn))
         return true;
+      /* FALLTHRU */
     case PROCESSOR_POWER4:
       if (is_microcoded_insn (insn))
         return true;
--- gcc/gcc/config/rs6000/rs6000.md
+++ gcc/gcc/config/rs6000/rs6000.md
@@ -8153,6 +8153,7 @@
     case 0:
       if (TARGET_STRING)
         return \"stswi %1,%P0,16\";
+      /* FALLTHRU */
     case 1:
       return \"#\";
     case 2:
@@ -8161,7 +8162,7 @@
       if (TARGET_STRING
           && ! reg_overlap_mentioned_p (operands[0], operands[1]))
 	return \"lswi %0,%P1,16\";
-      /* ... fall through ...  */
+      /* fall through */
     case 3:
     case 4:
     case 5:
--- gcc/gcc/cp/call.c
+++ gcc/gcc/cp/call.c
@@ -2421,6 +2421,7 @@ add_builtin_candidate (struct z_candidate **candidates, enum tree_code code,
     case PREDECREMENT_EXPR:
       if (TREE_CODE (type1) == BOOLEAN_TYPE)
 	return;
+      /* FALLTHRU */
     case POSTINCREMENT_EXPR:
     case PREINCREMENT_EXPR:
       if (ARITHMETIC_TYPE_P (type1) || TYPE_PTROB_P (type1))
@@ -2457,6 +2458,7 @@ add_builtin_candidate (struct z_candidate **candidates, enum tree_code code,
     case UNARY_PLUS_EXPR: /* unary + */
       if (TYPE_PTR_P (type1))
 	break;
+      /* FALLTHRU */
     case NEGATE_EXPR:
       if (ARITHMETIC_TYPE_P (type1))
 	break;
@@ -2594,6 +2596,7 @@ add_builtin_candidate (struct z_candidate **candidates, enum tree_code code,
     case PLUS_EXPR:
       if (ARITHMETIC_TYPE_P (type1) && ARITHMETIC_TYPE_P (type2))
 	break;
+      /* FALLTHRU */
     case ARRAY_REF:
       if (INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type1) && TYPE_PTROB_P (type2))
 	{
@@ -2674,6 +2677,7 @@ add_builtin_candidate (struct z_candidate **candidates, enum tree_code code,
 	      type2 = ptrdiff_type_node;
 	      break;
 	    }
+	  /* FALLTHRU */
 	case MULT_EXPR:
 	case TRUNC_DIV_EXPR:
 	  if (ARITHMETIC_TYPE_P (type1) && ARITHMETIC_TYPE_P (type2))
@@ -3966,7 +3970,7 @@ build_integral_nontype_arg_conv (tree type, tree expr, tsubst_flags_t complain)
 	if (complain & tf_error)
 	  error_at (loc, "conversion from %qT to %qT not considered for "
 		    "non-type template argument", t, type);
-	/* and fall through.  */
+	/* fall through.  */
 
       default:
 	conv = NULL;
@@ -5493,6 +5497,7 @@ build_new_op_1 (location_t loc, enum tree_code code, int flags, tree arg1,
     case MODIFY_EXPR:
       if (code2 != NOP_EXPR)
 	break;
+      /* FALLTHRU */
     case COMPONENT_REF:
     case ARRAY_REF:
       memonly = true;
@@ -6661,7 +6666,7 @@ convert_like_real (conversion *convs, tree expr, tree fn, int argnum,
 
       if (! MAYBE_CLASS_TYPE_P (totype))
 	return expr;
-      /* Else fall through.  */
+      /* Fall through.  */
     case ck_base:
       if (convs->kind == ck_base && !convs->need_temporary_p)
 	{
--- gcc/gcc/cp/class.c
+++ gcc/gcc/cp/class.c
@@ -7413,7 +7413,7 @@ fixed_type_or_null (tree instance, int *nonnull, int *cdtorp)
 	    *nonnull = 1;
 	  return TREE_TYPE (TREE_TYPE (instance));
 	}
-      /* fall through...  */
+      /* fall through.  */
     case TARGET_EXPR:
     case PARM_DECL:
     case RESULT_DECL:
--- gcc/gcc/cp/constexpr.c
+++ gcc/gcc/cp/constexpr.c
@@ -3693,7 +3693,7 @@ cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t,
       if (is_capture_proxy (t))
 	return cxx_eval_constant_expression (ctx, DECL_VALUE_EXPR (t),
 					     lval, non_constant_p, overflow_p);
-      /* else fall through.  */
+      /* fall through */
     case CONST_DECL:
       /* We used to not check lval for CONST_DECL, but darwin.c uses
 	 CONST_DECL for aggregate constants.  */
@@ -3982,7 +3982,7 @@ cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t,
 					    overflow_p);
       if (r)
 	break;
-      /* else fall through */
+      /* fall through */
 
     case PLUS_EXPR:
     case MINUS_EXPR:
@@ -5161,7 +5161,7 @@ potential_constant_expression_1 (tree t, bool want_rval, bool strict,
       /* A destructor.  */
       if (TYPE_P (TREE_OPERAND (t, 0)))
 	return true;
-      /* else fall through.  */
+      /* fall through.  */
 
     case REALPART_EXPR:
     case IMAGPART_EXPR:
@@ -5263,6 +5263,7 @@ potential_constant_expression_1 (tree t, bool want_rval, bool strict,
 	    }
 	  return false;
 	}
+      /* FALLTHRU */
     case INIT_EXPR:
       return RECUR (TREE_OPERAND (t, 1), rval);
 
--- gcc/gcc/cp/cp-gimplify.c
+++ gcc/gcc/cp/cp-gimplify.c
@@ -659,7 +659,7 @@ cp_gimplify_expr (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p)
       cp_gimplify_init_expr (expr_p);
       if (TREE_CODE (*expr_p) != INIT_EXPR)
 	return GS_OK;
-      /* Otherwise fall through.  */
+      /* Fall through.  */
     case MODIFY_EXPR:
     modify_expr_case:
       {
@@ -2068,6 +2068,7 @@ cp_fold (tree x)
 
     case VIEW_CONVERT_EXPR:
       rval_ops = false;
+      /* FALLTHRU */
     case CONVERT_EXPR:
     case NOP_EXPR:
     case NON_LVALUE_EXPR:
@@ -2116,6 +2117,7 @@ cp_fold (tree x)
     case REALPART_EXPR:
     case IMAGPART_EXPR:
       rval_ops = false;
+      /* FALLTHRU */
     case CONJ_EXPR:
     case FIX_TRUNC_EXPR:
     case FLOAT_EXPR:
@@ -2168,6 +2170,7 @@ cp_fold (tree x)
     case COMPOUND_EXPR:
     case MODIFY_EXPR:
       rval_ops = false;
+      /* FALLTHRU */
     case POINTER_PLUS_EXPR:
     case PLUS_EXPR:
     case MINUS_EXPR:
--- gcc/gcc/cp/cvt.c
+++ gcc/gcc/cp/cvt.c
@@ -1663,7 +1663,7 @@ build_expr_type_conversion (int desires, tree expr, bool complain)
       case INTEGER_TYPE:
 	if ((desires & WANT_NULL) && null_ptr_cst_p (expr))
 	  return expr;
-	/* else fall through...  */
+	/* fall through.  */
 
       case BOOLEAN_TYPE:
 	return (desires & WANT_INT) ? expr : NULL_TREE;
--- gcc/gcc/cp/cxx-pretty-print.c
+++ gcc/gcc/cp/cxx-pretty-print.c
@@ -153,6 +153,7 @@ pp_cxx_unqualified_id (cxx_pretty_printer *pp, tree t)
     case USING_DECL:
     case TEMPLATE_DECL:
       t = DECL_NAME (t);
+      /* FALLTHRU */
 
     case IDENTIFIER_NODE:
       if (t == NULL)
@@ -280,6 +281,7 @@ pp_cxx_qualified_id (cxx_pretty_printer *pp, tree t)
 	 functions and some function templates.  */
     case OVERLOAD:
       t = OVL_CURRENT (t);
+      /* FALLTHRU */
     case FUNCTION_DECL:
       if (DECL_FUNCTION_MEMBER_P (t))
 	pp_cxx_nested_name_specifier (pp, DECL_CONTEXT (t));
@@ -331,7 +333,7 @@ cxx_pretty_printer::constant (tree t)
 	  pp_string (this, "nullptr");
 	  break;
 	}
-      /* else fall through.  */
+      /* fall through.  */
 
     default:
       c_pretty_printer::constant (t);
@@ -417,6 +419,7 @@ cxx_pretty_printer::primary_expression (tree t)
 
     case BASELINK:
       t = BASELINK_FUNCTIONS (t);
+      /* FALLTHRU */
     case VAR_DECL:
     case PARM_DECL:
     case FIELD_DECL:
@@ -872,7 +875,7 @@ pp_cxx_pm_expression (cxx_pretty_printer *pp, tree t)
 	  pp_cxx_qualified_id (pp, t);
 	  break;
 	}
-      /* Else fall through.  */
+      /* Fall through.  */
     case MEMBER_REF:
     case DOTSTAR_EXPR:
       pp_cxx_pm_expression (pp, TREE_OPERAND (t, 0));
@@ -1057,6 +1060,7 @@ cxx_pretty_printer::expression (tree t)
 
     case OVERLOAD:
       t = OVL_CURRENT (t);
+      /* FALLTHRU */
     case VAR_DECL:
     case PARM_DECL:
     case FIELD_DECL:
@@ -1267,7 +1271,9 @@ cxx_pretty_printer::declaration_specifiers (tree t)
       else if (DECL_NONSTATIC_MEMBER_FUNCTION_P (t))
 	declaration_specifiers (TREE_TYPE (TREE_TYPE (t)));
       else
-	default:
+        c_pretty_printer::declaration_specifiers (t);
+      break;
+    default:
         c_pretty_printer::declaration_specifiers (t);
       break;
     }
@@ -1364,7 +1370,7 @@ pp_cxx_type_specifier_seq (cxx_pretty_printer *pp, tree t)
 	  pp_cxx_ptr_operator (pp, t);
 	  break;
 	}
-      /* else fall through */
+      /* fall through */
 
     default:
       if (!(TREE_CODE (t) == FUNCTION_DECL && DECL_CONSTRUCTOR_P (t)))
@@ -1406,6 +1412,7 @@ pp_cxx_ptr_operator (cxx_pretty_printer *pp, tree t)
 	  pp_star (pp);
 	  break;
 	}
+      /* FALLTHRU */
     case OFFSET_TYPE:
       if (TYPE_PTRMEM_P (t))
 	{
@@ -1416,7 +1423,7 @@ pp_cxx_ptr_operator (cxx_pretty_printer *pp, tree t)
 	  pp_cxx_cv_qualifier_seq (pp, t);
 	  break;
 	}
-      /* else fall through.  */
+      /* fall through.  */
 
     default:
       pp_unsupported_tree (pp, t);
--- gcc/gcc/cp/error.c
+++ gcc/gcc/cp/error.c
@@ -450,7 +450,7 @@ dump_type (cxx_pretty_printer *pp, tree t, int flags)
 		     ? DECL_ORIGINAL_TYPE (t) : TREE_TYPE (t), flags);
 	  break;
 	}
-      /* Else fall through.  */
+      /* Fall through.  */
 
     case TEMPLATE_DECL:
     case NAMESPACE_DECL:
@@ -1065,7 +1066,7 @@ dump_decl (cxx_pretty_printer *pp, tree t, int flags)
 	  dump_type (pp, DECL_CONTEXT (t), flags);
 	  break;
 	}
-      /* Else fall through.  */
+      /* Fall through.  */
     case FIELD_DECL:
     case PARM_DECL:
       dump_simple_decl (pp, t, TREE_TYPE (t), flags);
--- gcc/gcc/cp/mangle.c
+++ gcc/gcc/cp/mangle.c
@@ -2169,7 +2169,7 @@ write_type (tree type)
 		  ++is_builtin_type;
 		  break;
 		}
-	      /* else fall through.  */
+	      /* fall through.  */
 	    case TEMPLATE_PARM_INDEX:
 	      write_template_param (type);
 	      break;
--- gcc/gcc/cp/method.c
+++ gcc/gcc/cp/method.c
@@ -1420,6 +1420,7 @@ synthesized_method_walk (tree ctype, special_function_kind sfk, bool const_p,
     case sfk_move_constructor:
     case sfk_move_assignment:
       move_p = true;
+      /* FALLTHRU */
     case sfk_copy_constructor:
     case sfk_copy_assignment:
       copy_arg_p = true;
--- gcc/gcc/cp/name-lookup.c
+++ gcc/gcc/cp/name-lookup.c
@@ -5659,6 +5659,7 @@ arg_assoc_type (struct arg_lookup *k, tree type)
     case RECORD_TYPE:
       if (TYPE_PTRMEMFUNC_P (type))
 	return arg_assoc_type (k, TYPE_PTRMEMFUNC_FN_TYPE (type));
+      /* FALLTHRU */
     case UNION_TYPE:
       return arg_assoc_class (k, type);
     case POINTER_TYPE:
--- gcc/gcc/cp/parser.c
+++ gcc/gcc/cp/parser.c
@@ -1268,7 +1268,7 @@ cp_lexer_print_token (FILE * stream, cp_token *token)
 	 For example, `struct' is mapped to an INTEGER_CST.  */
       if (!identifier_p (token->u.value))
 	break;
-      /* else fall through */
+      /* fall through */
     case CPP_NAME:
       fputs (IDENTIFIER_POINTER (token->u.value), stream);
       break;
@@ -5143,6 +5143,7 @@ cp_parser_primary_expression (cp_parser *parser,
 	      cp_parser_skip_to_end_of_block_or_statement (parser);
 	      return error_mark_node;
 	    }
+	  /* FALLTHRU */
 	default:
 	  cp_parser_error (parser, "expected primary-expression");
 	  return error_mark_node;
@@ -14096,6 +14098,7 @@ cp_parser_operator (cp_parser* parser)
     case CPP_UTF8STRING:
     case CPP_UTF8STRING_USERDEF:
       utf8 = true;
+      /* FALLTHRU */
     case CPP_STRING:
     case CPP_WSTRING:
     case CPP_STRING16:
--- gcc/gcc/cp/pt.c
+++ gcc/gcc/cp/pt.c
@@ -3450,6 +3450,7 @@ find_parameter_packs_r (tree *tp, int *walk_subtrees, void* data)
 
     case TEMPLATE_TYPE_PARM:
       t = TYPE_MAIN_VARIANT (t);
+      /* FALLTHRU */
     case TEMPLATE_TEMPLATE_PARM:
       /* If the placeholder appears in the decl-specifier-seq of a function
 	 parameter pack (14.6.3), or the type-specifier-seq of a type-id that
@@ -11466,7 +11467,7 @@ tsubst_aggr_type (tree t,
       if (TYPE_PTRMEMFUNC_P (t))
 	return tsubst (TYPE_PTRMEMFUNC_FN_TYPE (t), args, complain, in_decl);
 
-      /* Else fall through.  */
+      /* Fall through.  */
     case ENUMERAL_TYPE:
     case UNION_TYPE:
       if (TYPE_TEMPLATE_INFO (t) && uses_template_parms (t))
--- gcc/gcc/cp/semantics.c
+++ gcc/gcc/cp/semantics.c
@@ -6225,11 +6225,13 @@ finish_omp_clauses (tree clauses, enum c_omp_region_type ort)
 	      OMP_CLAUSE_OPERAND (c, 1) = t;
 	    }
 	  /* Check operand 0, the num argument.  */
+	  /* FALLTHRU */
 
 	case OMP_CLAUSE_WORKER:
 	case OMP_CLAUSE_VECTOR:
 	  if (OMP_CLAUSE_OPERAND (c, 0) == NULL_TREE)
 	    break;
+	  /* FALLTHRU */
 
 	case OMP_CLAUSE_NUM_TASKS:
 	case OMP_CLAUSE_NUM_TEAMS:
--- gcc/gcc/cp/tree.c
+++ gcc/gcc/cp/tree.c
@@ -141,11 +141,13 @@ lvalue_kind (const_tree ref)
 	 lvalues.  */
       if (! TREE_STATIC (ref))
 	return clk_none;
+      /* FALLTHRU */
     case VAR_DECL:
       if (TREE_READONLY (ref) && ! TREE_STATIC (ref)
 	  && DECL_LANG_SPECIFIC (ref)
 	  && DECL_IN_AGGR_P (ref))
 	return clk_none;
+      /* FALLTHRU */
     case INDIRECT_REF:
     case ARROW_EXPR:
     case ARRAY_REF:
--- gcc/gcc/dbxout.c
+++ gcc/gcc/dbxout.c
@@ -2867,7 +2867,7 @@ dbxout_symbol (tree decl, int local ATTRIBUTE_UNUSED)
 	 disguised VAR_DECLs like Out parameters in Ada.  */
       gcc_assert (TREE_CODE (decl) == VAR_DECL);
 
-      /* ... fall through ...  */
+      /* fall through */
 
     case RESULT_DECL:
     case VAR_DECL:
--- gcc/gcc/df-scan.c
+++ gcc/gcc/df-scan.c
@@ -2875,7 +2875,7 @@ df_uses_record (struct df_collection_rec *collection_rec,
 	  df_uses_record (collection_rec, loc, ref_type, bb, insn_info, flags);
 	  return;
 	}
-      /* ... Fall through ...  */
+      /* Fall through */
 
     case REG:
       df_ref_record (DF_REF_REGULAR, collection_rec,
--- gcc/gcc/dojump.c
+++ gcc/gcc/dojump.c
@@ -461,12 +461,14 @@ do_jump (tree exp, rtx_code_label *if_false_label,
           || TREE_CODE (TREE_OPERAND (exp, 0)) == ARRAY_REF
           || TREE_CODE (TREE_OPERAND (exp, 0)) == ARRAY_RANGE_REF)
         goto normal;
+      /* FALLTHRU */
     case CONVERT_EXPR:
       /* If we are narrowing the operand, we have to do the compare in the
          narrower mode.  */
       if ((TYPE_PRECISION (TREE_TYPE (exp))
            < TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (exp, 0)))))
         goto normal;
+      /* FALLTHRU */
     case NON_LVALUE_EXPR:
     case ABS_EXPR:
     case NEGATE_EXPR:
@@ -610,6 +612,7 @@ do_jump (tree exp, rtx_code_label *if_false_label,
 	goto normal;
 
       /* Boolean comparisons can be compiled as TRUTH_AND_EXPR.  */
+      /* FALLTHRU */
 
     case TRUTH_AND_EXPR:
       /* High branch cost, expand as the bitwise AND of the conditions.
--- gcc/gcc/dwarf2out.c
+++ gcc/gcc/dwarf2out.c
@@ -13334,6 +13334,7 @@ mem_loc_descriptor (rtx rtl, machine_mode mode,
       if (!subreg_lowpart_p (rtl))
 	break;
       inner = SUBREG_REG (rtl);
+      /* FALLTHRU */
     case TRUNCATE:
       if (inner == NULL_RTX)
         inner = XEXP (rtl, 0);
@@ -13671,7 +13672,7 @@ mem_loc_descriptor (rtx rtl, machine_mode mode,
 					: -GET_MODE_UNIT_SIZE (mem_mode),
 					mode));
 
-      /* ... fall through ...  */
+      /* fall through */
 
     case PLUS:
     plus:
@@ -15597,7 +15598,7 @@ resolve_args_picking_1 (dw_loc_descr_ref loc, unsigned initial_frame_offset,
 	  if (!resolve_args_picking_1 (l->dw_loc_next, frame_offset_, dpi,
 				       frame_offsets))
 	    return false;
-	  /* Fall through... */
+	  /* Fall through. */
 
 	case DW_OP_skip:
 	  l = l->dw_loc_oprnd1.v.val_loc;
@@ -16350,7 +16351,7 @@ loc_list_from_tree_1 (tree loc, int want_address,
 		      TREE_OPERAND (loc, 1), TREE_OPERAND (loc, 0));
       }
 
-      /* ... fall through ...  */
+      /* fall through */
 
     case COND_EXPR:
       {
--- gcc/gcc/expmed.c
+++ gcc/gcc/expmed.c
@@ -5173,7 +5173,7 @@ make_tree (tree type, rtx x)
       t = SYMBOL_REF_DECL (x);
       if (t)
 	return fold_convert (type, build_fold_addr_expr (t));
-      /* else fall through.  */
+      /* fall through.  */
 
     default:
       t = build_decl (RTL_LOCATION (x), VAR_DECL, NULL_TREE, type);
--- gcc/gcc/expr.c
+++ gcc/gcc/expr.c
@@ -8406,6 +8406,7 @@ expand_expr_real_2 (sepops ops, rtx target, machine_mode tmode,
 	 offset to have matching modes.  */
       else if (TYPE_PRECISION (sizetype) > TYPE_PRECISION (type))
 	treeop1 = fold_convert_loc (loc, type, treeop1);
+      /* FALLTHRU */
 
     case PLUS_EXPR:
       /* If we are adding a constant, a VAR_DECL that is sp, fp, or ap, and
@@ -9574,9 +9575,9 @@ expand_expr_real_1 (tree exp, rtx target, machine_mode tmode,
     switch (TREE_CODE_LENGTH (code))
       {
 	default:
-	case 3: treeop2 = TREE_OPERAND (exp, 2);
-	case 2: treeop1 = TREE_OPERAND (exp, 1);
-	case 1: treeop0 = TREE_OPERAND (exp, 0);
+	case 3: treeop2 = TREE_OPERAND (exp, 2); /* FALLTHRU */
+	case 2: treeop1 = TREE_OPERAND (exp, 1); /* FALLTHRU */
+	case 1: treeop0 = TREE_OPERAND (exp, 0); /* FALLTHRU */
 	case 0: break;
       }
   ops.code = code;
@@ -9748,7 +9749,7 @@ expand_expr_real_1 (tree exp, rtx target, machine_mode tmode,
 	  && (TREE_STATIC (exp) || DECL_EXTERNAL (exp)))
 	layout_decl (exp, 0);
 
-      /* ... fall through ...  */
+      /* fall through */
 
     case FUNCTION_DECL:
     case RESULT_DECL:
@@ -9956,7 +9957,7 @@ expand_expr_real_1 (tree exp, rtx target, machine_mode tmode,
 	  return original_target;
 	}
 
-      /* ... fall through ...  */
+      /* fall through */
 
     case STRING_CST:
       temp = expand_expr_constant (exp, 1, modifier);
--- gcc/gcc/fold-const.c
+++ gcc/gcc/fold-const.c
@@ -1300,7 +1300,7 @@ const_binop (enum tree_code code, tree arg1, tree arg2)
 	    return do_mpc_arg2 (arg1, arg2, type,
                                 /* do_nonfinite= */ folding_initializer,
 				mpc_div);
-	  /* Fallthru ... */
+	  /* Fallthru. */
 	case TRUNC_DIV_EXPR:
 	case CEIL_DIV_EXPR:
 	case FLOOR_DIV_EXPR:
@@ -3696,7 +3696,7 @@ fold_truth_not_expr (location_t loc, tree arg)
       if (TREE_CODE (TREE_TYPE (arg)) == BOOLEAN_TYPE)
 	return build1_loc (loc, TRUTH_NOT_EXPR, type, arg);
 
-      /* ... fall through ...  */
+      /* fall through */
 
     case FLOAT_EXPR:
       loc1 = expr_location_or (TREE_OPERAND (arg, 0), loc);
@@ -5101,6 +5101,7 @@ fold_cond_expr_with_comparison (location_t loc, tree type,
       case UNLT_EXPR:
 	if (flag_trapping_math)
 	  break;
+	/* FALLTHRU */
       case LE_EXPR:
       case LT_EXPR:
 	if (TYPE_UNSIGNED (TREE_TYPE (arg1)))
@@ -10323,6 +10324,7 @@ fold_binary_loc (location_t loc,
       /* If first arg is constant zero, return it.  */
       if (integer_zerop (arg0))
 	return fold_convert_loc (loc, type, arg0);
+      /* FALLTHRU */
     case TRUTH_AND_EXPR:
       /* If either arg is constant true, drop it.  */
       if (TREE_CODE (arg0) == INTEGER_CST && ! integer_zerop (arg0))
@@ -10378,6 +10380,7 @@ fold_binary_loc (location_t loc,
       /* If first arg is constant true, return it.  */
       if (TREE_CODE (arg0) == INTEGER_CST && ! integer_zerop (arg0))
 	return fold_convert_loc (loc, type, arg0);
+      /* FALLTHRU */
     case TRUTH_OR_EXPR:
       /* If either arg is constant zero, drop it.  */
       if (TREE_CODE (arg0) == INTEGER_CST && integer_zerop (arg0))
@@ -11222,7 +11225,7 @@ contains_label_1 (tree *tp, int *walk_subtrees, void *data ATTRIBUTE_UNUSED)
     case GOTO_EXPR:
       *walk_subtrees = 0;
 
-      /* ... fall through ...  */
+      /* fall through */
 
     default:
       return NULL_TREE;
@@ -12602,7 +12605,7 @@ multiple_of_p (tree type, const_tree top, const_tree bottom)
 	      < TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (top, 0)))))
 	return 0;
 
-      /* .. fall through ...  */
+      /* fall through */
 
     case SAVE_EXPR:
       return multiple_of_p (type, TREE_OPERAND (top, 0), bottom);
@@ -12657,7 +12660,7 @@ multiple_of_p (tree type, const_tree top, const_tree bottom)
 	    return 1;
 	}
 
-      /* .. fall through ...  */
+      /* fall through */
 
     default:
       return 0;
--- gcc/gcc/fortran/decl.c
+++ gcc/gcc/fortran/decl.c
@@ -3927,6 +3927,7 @@ match_attr_spec (void)
 		      d = DECL_CODIMENSION;
 		      break;
 		    }
+		  /* FALLTHRU */
 		case 'n':
 		  if (match_string_p ("tiguous"))
 		    {
--- gcc/gcc/fortran/primary.c
+++ gcc/gcc/fortran/primary.c
@@ -1686,18 +1686,21 @@ match_arg_list_function (gfc_actual_arglist *result)
 	      result->name = "%LOC";
 	      break;
 	    }
+	  /* FALLTHRU */
 	case 'r':
 	  if (strncmp (name, "ref", 3) == 0)
 	    {
 	      result->name = "%REF";
 	      break;
 	    }
+	  /* FALLTHRU */
 	case 'v':
 	  if (strncmp (name, "val", 3) == 0)
 	    {
 	      result->name = "%VAL";
 	      break;
 	    }
+	  /* FALLTHRU */
 	default:
 	  m = MATCH_ERROR;
 	  goto cleanup;
--- gcc/gcc/fortran/resolve.c
+++ gcc/gcc/fortran/resolve.c
@@ -3542,7 +3542,7 @@ resolve_operator (gfc_expr *e)
       if (!gfc_resolve_expr (e->value.op.op2))
 	return false;
 
-    /* Fall through...  */
+    /* Fall through.  */
 
     case INTRINSIC_NOT:
     case INTRINSIC_UPLUS:
@@ -3660,7 +3660,7 @@ resolve_operator (gfc_expr *e)
 	  goto bad_op;
 	}
 
-      /* Fall through...  */
+      /* Fall through.  */
 
     case INTRINSIC_EQ:
     case INTRINSIC_EQ_OS:
@@ -5419,14 +5419,17 @@ fixup_charlen (gfc_expr *e)
     {
     case EXPR_OP:
       gfc_resolve_character_operator (e);
+      /* FALLTHRU */
 
     case EXPR_ARRAY:
       if (e->expr_type == EXPR_ARRAY)
 	gfc_resolve_character_array_constructor (e);
+      /* FALLTHRU */
 
     case EXPR_SUBSTRING:
       if (!e->ts.u.cl && e->ref)
 	gfc_resolve_substring_charlen (e);
+      /* FALLTHRU */
 
     default:
       if (!e->ts.u.cl)
@@ -7301,7 +7304,7 @@ resolve_allocate_expr (gfc_expr *e, gfc_code *code, bool *array_alloc_wo_spec)
 	      && ar->stride[i] == NULL)
 	    break;
 
-	  /* Fall Through...  */
+	  /* Fall through.  */
 
 	case DIMEN_UNKNOWN:
 	case DIMEN_VECTOR:
--- gcc/gcc/fortran/trans-array.c
+++ gcc/gcc/fortran/trans-array.c
@@ -4041,6 +4042,7 @@ done:
 	      continue;
 	    }
 
+	  /* FALLTHRU */
 	case GFC_SS_CONSTRUCTOR:
 	case GFC_SS_FUNCTION:
 	  for (n = 0; n < ss->dimen; n++)
diff --git gcc/gcc/fortran/trans-intrinsic.c gcc/gcc/fortran/trans-intrinsic.c
index abc1c6d..17dd8c2 100644
--- gcc/gcc/fortran/trans-intrinsic.c
+++ gcc/gcc/fortran/trans-intrinsic.c
@@ -5329,7 +5329,7 @@ gfc_conv_intrinsic_len (gfc_se * se, gfc_expr * expr)
 	  break;
 	}
 
-      /* Otherwise fall through.  */
+      /* Fall through.  */
 
     default:
       /* Anybody stupid enough to do this deserves inefficient code.  */
--- gcc/gcc/gcov-tool.c
+++ gcc/gcc/gcov-tool.c
@@ -547,9 +547,11 @@ process_args (int argc, char **argv)
         case 'h':
           print_usage (false);
           /* Print_usage will exit.  */
+	  /* FALLTHRU */
         case 'v':
           print_version ();
           /* Print_version will exit.  */
+	  /* FALLTHRU */
         default:
           print_usage (true);
           /* Print_usage will exit.  */
--- gcc/gcc/genattrtab.c
+++ gcc/gcc/genattrtab.c
@@ -888,6 +888,7 @@ check_attr_test (file_location loc, rtx exp, attr_desc *attr)
 	  ATTR_IND_SIMPLIFIED_P (exp) = 1;
 	  break;
 	}
+      /* FALLTHRU */
     default:
       fatal_at (loc, "invalid operator `%s' in definition of attribute"
 		" `%s'", GET_RTX_NAME (GET_CODE (exp)), attr->name);
@@ -3458,6 +3460,7 @@ write_test_expr (FILE *outf, rtx exp, unsigned int attrs_cached, int flags,
     case GE: case GT:
     case LE: case LT:
       comparison_operator = FLG_BITWISE;
+      /* FALLTHRU */
 
     case PLUS:   case MINUS:  case MULT:     case DIV:      case MOD:
     case AND:    case IOR:    case XOR:
--- gcc/gcc/genconfig.c
+++ gcc/gcc/genconfig.c
@@ -83,6 +83,7 @@ walk_insn_part (rtx part, int recog_p, int non_pc_set_src)
     case MATCH_OP_DUP:
     case MATCH_PAR_DUP:
       ++dup_operands_seen_this_insn;
+      /* FALLTHRU */
     case MATCH_SCRATCH:
     case MATCH_PARALLEL:
     case MATCH_OPERATOR:
--- gcc/gcc/genpreds.c
+++ gcc/gcc/genpreds.c
@@ -51,12 +51,12 @@ validate_exp (rtx exp, const char *name, file_location loc)
     case IF_THEN_ELSE:
       if (validate_exp (XEXP (exp, 2), name, loc))
 	return true;
-      /* else fall through */
+      /* fall through */
     case AND:
     case IOR:
       if (validate_exp (XEXP (exp, 1), name, loc))
 	return true;
-      /* else fall through */
+      /* fall through */
     case NOT:
       return validate_exp (XEXP (exp, 0), name, loc);
 
@@ -174,12 +174,12 @@ needs_variable (rtx exp, const char *var)
     case IF_THEN_ELSE:
       if (needs_variable (XEXP (exp, 2), var))
 	return true;
-      /* else fall through */
+      /* fall through */
     case AND:
     case IOR:
       if (needs_variable (XEXP (exp, 1), var))
 	return true;
-      /* else fall through */
+      /* fall through */
     case NOT:
       return needs_variable (XEXP (exp, 0), var);
 
--- gcc/gcc/gensupport.c
+++ gcc/gcc/gensupport.c
@@ -1038,6 +1038,7 @@ get_alternatives_number (rtx pattern, int *n_alt, file_location loc)
 	case 'V':
 	  if (XVEC (pattern, i) == NULL)
 	    break;
+	  /* FALLTHRU */
 
 	case 'E':
 	  for (j = XVECLEN (pattern, i) - 1; j >= 0; --j)
@@ -2156,6 +2157,7 @@ subst_dup (rtx pattern, int n_alt, int n_subst_alt)
 	case 'V':
 	  if (XVEC (pattern, i) == NULL)
 	    break;
+	  /* FALLTHRU */
 	case 'E':
 	  if (code != MATCH_DUP && code != MATCH_OP_DUP)
 	    for (j = XVECLEN (pattern, i) - 1; j >= 0; --j)
--- gcc/gcc/gimple-pretty-print.c
+++ gcc/gcc/gimple-pretty-print.c
@@ -517,8 +517,10 @@ dump_gimple_assign (pretty_printer *buffer, gassign *gs, int spc, int flags)
 	{
 	case 4:
 	  arg3 = gimple_assign_rhs3 (gs);
+	  /* FALLTHRU */
 	case 3:
 	  arg2 = gimple_assign_rhs2 (gs);
+	  /* FALLTHRU */
 	case 2:
 	  arg1 = gimple_assign_rhs1 (gs);
 	  break;
--- gcc/gcc/gimplify.c
+++ gcc/gcc/gimplify.c
@@ -5190,7 +5190,7 @@ gimplify_addr_expr (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p)
       if (integer_zerop (TREE_OPERAND (op0, 1)))
 	goto do_indirect_ref;
 
-      /* ... fall through ... */
+      /* fall through */
 
     default:
       /* If we see a call to a declared builtin or see its address
@@ -6941,6 +6941,7 @@ gimplify_scan_omp_clauses (tree *list_p, gimple_seq *pre_p,
 	    case OACC_DATA:
 	      if (TREE_CODE (TREE_TYPE (decl)) != ARRAY_TYPE)
 		break;
+	      /* FALLTHRU */
 	    case OMP_TARGET_DATA:
 	    case OMP_TARGET_ENTER_DATA:
 	    case OMP_TARGET_EXIT_DATA:
@@ -9964,6 +9965,7 @@ goa_stabilize_expr (tree *expr_p, gimple_seq *pre_p, tree lhs_addr,
     case tcc_comparison:
       saw_lhs |= goa_stabilize_expr (&TREE_OPERAND (expr, 1), pre_p, lhs_addr,
 				     lhs_var);
+      /* FALLTHRU */
     case tcc_unary:
       saw_lhs |= goa_stabilize_expr (&TREE_OPERAND (expr, 0), pre_p, lhs_addr,
 				     lhs_var);
@@ -9978,6 +9980,7 @@ goa_stabilize_expr (tree *expr_p, gimple_seq *pre_p, tree lhs_addr,
 	case TRUTH_XOR_EXPR:
 	  saw_lhs |= goa_stabilize_expr (&TREE_OPERAND (expr, 1), pre_p,
 					 lhs_addr, lhs_var);
+	  /* FALLTHRU */
 	case TRUTH_NOT_EXPR:
 	  saw_lhs |= goa_stabilize_expr (&TREE_OPERAND (expr, 0), pre_p,
 					 lhs_addr, lhs_var);
--- gcc/gcc/graphite-isl-ast-to-gimple.c
+++ gcc/gcc/graphite-isl-ast-to-gimple.c
@@ -1496,7 +1496,7 @@ substitute_ssa_name (tree exp, tree f, tree r)
 	if (exp == f)
 	  return r;
 
-	/* Fall through...  */
+	/* Fall through.  */
 
       case tcc_exceptional:
       case tcc_unary:
--- gcc/gcc/hsa-gen.c
+++ gcc/gcc/hsa-gen.c
@@ -4519,7 +4519,7 @@ get_address_from_value (tree val, hsa_bb *hbb)
     case INTEGER_CST:
       if (tree_fits_shwi_p (val))
 	return new hsa_op_address (NULL, NULL, tree_to_shwi (val));
-      /* Otherwise fall-through */
+      /* fall-through */
 
     default:
       HSA_SORRY_ATV (EXPR_LOCATION (val),
--- gcc/gcc/ipa-icf.c
+++ gcc/gcc/ipa-icf.c
@@ -1643,7 +1643,7 @@ sem_function::hash_stmt (gimple *stmt, inchash::hash &hstate)
 	  add_type (TREE_TYPE (gimple_assign_lhs (stmt)), two);
 	  break;
 	}
-      /* ... fall through ... */
+      /* fall through */
     case GIMPLE_CALL:
     case GIMPLE_ASM:
     case GIMPLE_COND:
--- gcc/gcc/ira.c
+++ gcc/gcc/ira.c
@@ -1832,6 +1832,7 @@ ira_setup_alts (rtx_insn *insn, HARD_REG_SET &alts)
 		  case '#':
 		  case ',':
 		    c = '\0';
+		    /* FALLTHRU */
 		  case '\0':
 		    len = 0;
 		    break;
--- gcc/gcc/java/expr.c
+++ gcc/gcc/java/expr.c
@@ -192,7 +192,7 @@ java_truthvalue_conversion (tree expr)
       if (TYPE_PRECISION (TREE_TYPE (expr))
           >= TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (expr, 0))))
         return java_truthvalue_conversion (TREE_OPERAND (expr, 0));
-      /* fall through to default */
+      /* fall through */
 
     default:
       return fold_build2 (NE_EXPR, boolean_type_node,
--- gcc/gcc/java/jcf-io.c
+++ gcc/gcc/java/jcf-io.c
@@ -471,7 +471,7 @@ verify_constant_pool (JCF *jcf)
 	  if (n <= 0 || n >= JPOOL_SIZE(jcf)
 	      || JPOOL_TAG (jcf, n) != CONSTANT_Utf8)
 	    return i;
-	  /* ... fall through ... */
+	  /* fall through */
 	case CONSTANT_Class:
 	case CONSTANT_String:
 	  n = JPOOL_USHORT1 (jcf, i);
--- gcc/gcc/java/typeck.c
+++ gcc/gcc/java/typeck.c
@@ -341,7 +341,7 @@ promote_type (tree type)
 	    return promoted_byte_type_node;
 	  return int_type_node;
 	}
-      /* ... else fall through ... */
+      /* fall through */
     default:
       return type;
     }
--- gcc/gcc/lra-eliminations.c
+++ gcc/gcc/lra-eliminations.c
@@ -484,7 +484,7 @@ lra_eliminate_regs_1 (rtx_insn *insn, rtx x, machine_mode mem_mode,
 	    return gen_rtx_MULT (Pmode, to, XEXP (x, 1));
 	}
 
-      /* ... fall through ...  */
+      /* fall through */
 
     case CALL:
     case COMPARE:
@@ -536,7 +536,7 @@ lra_eliminate_regs_1 (rtx_insn *insn, rtx x, machine_mode mem_mode,
 	    }
 	}
 
-      /* ... fall through ...  */
+      /* fall through */
 
     case INSN_LIST:
     case INT_LIST:
--- gcc/gcc/lto-streamer-out.c
+++ gcc/gcc/lto-streamer-out.c
@@ -231,6 +231,7 @@ lto_output_tree_ref (struct output_block *ob, tree expr)
     case VAR_DECL:
     case DEBUG_EXPR_DECL:
       gcc_assert (decl_function_context (expr) == NULL || TREE_STATIC (expr));
+      /* FALLTHRU */
     case PARM_DECL:
       streamer_write_record_start (ob, LTO_global_decl_ref);
       lto_output_var_decl_index (ob->decl_state, ob->main_stream, expr);
--- gcc/gcc/objc/objc-encoding.c
+++ gcc/gcc/objc/objc-encoding.c
@@ -622,6 +622,7 @@ encode_type (tree type, int curtype, int format)
 	}
       /* Else, they are encoded exactly like the integer type that is
 	 used by the compiler to store them.  */
+      /* FALLTHRU */
     case INTEGER_TYPE:
       {
 	char c;
--- gcc/gcc/opts.c
+++ gcc/gcc/opts.c
@@ -1980,6 +1980,7 @@ common_handle_option (struct gcc_options *opts,
       opts->x_flag_profile_use = true;
       value = true;
       /* No break here - do -fprofile-use processing. */
+      /* FALLTHRU */
     case OPT_fprofile_use:
       enable_fdo_optimizations (opts, opts_set, value);
       if (!opts_set->x_flag_profile_reorder_functions)
@@ -1996,6 +1997,7 @@ common_handle_option (struct gcc_options *opts,
       opts->x_flag_auto_profile = true;
       value = true;
       /* No break here - do -fauto-profile processing. */
+      /* FALLTHRU */
     case OPT_fauto_profile:
       enable_fdo_optimizations (opts, opts_set, value);
       if (!opts_set->x_flag_profile_correction)
@@ -2009,6 +2011,7 @@ common_handle_option (struct gcc_options *opts,
       opts->x_profile_data_prefix = xstrdup (arg);
       value = true;
       /* No break here - do -fprofile-generate processing. */
+      /* FALLTHRU */
     case OPT_fprofile_generate:
       if (!opts_set->x_profile_arc_flag)
 	opts->x_profile_arc_flag = value;
--- gcc/gcc/read-rtl.c
+++ gcc/gcc/read-rtl.c
@@ -1163,6 +1163,7 @@ read_rtx_code (const char *code_name)
 	    break;
 	  }
 	/* Now process the vector.  */
+	/* FALLTHRU */
 
       case 'E':
 	{
--- gcc/gcc/real.c
+++ gcc/gcc/real.c
@@ -2667,6 +2667,7 @@ round_for_format (const struct real_format *fmt, REAL_VALUE_TYPE *r)
     {
     underflow:
       get_zero (r, r->sign);
+      /* FALLTHRU */
     case rvc_zero:
       if (!fmt->has_signed_zero)
 	r->sign = 0;
--- gcc/gcc/recog.c
+++ gcc/gcc/recog.c
@@ -1792,6 +1792,7 @@ asm_operand_ok (rtx op, const char *constraint, const char **constraints)
 
 	     Match any memory and hope things are resolved after reload.  */
 	  incdec_ok = true;
+	  /* FALLTHRU */
 	default:
 	  cn = lookup_constraint (constraint);
 	  switch (get_constraint_type (cn))
--- gcc/gcc/reginfo.c
+++ gcc/gcc/reginfo.c
@@ -1149,7 +1149,7 @@ reg_scan_mark_refs (rtx x, rtx_insn *insn)
       if (REG_P (dest) && !REG_ATTRS (dest))
 	set_reg_attrs_from_value (dest, SET_SRC (x));
 
-      /* ... fall through ...  */
+      /* fall through */
 
     default:
       {
--- gcc/gcc/reload1.c
+++ gcc/gcc/reload1.c
@@ -2328,7 +2328,7 @@ set_label_offsets (rtx x, rtx_insn *insn, int initial_p)
 
       x = LABEL_REF_LABEL (x);
 
-      /* ... fall through ...  */
+      /* fall through */
 
     case CODE_LABEL:
       /* If we know nothing about this label, set the desired offsets.  Note
@@ -2375,7 +2375,7 @@ set_label_offsets (rtx x, rtx_insn *insn, int initial_p)
     case JUMP_INSN:
       set_label_offsets (PATTERN (insn), insn, initial_p);
 
-      /* ... fall through ...  */
+      /* fall through */
 
     case INSN:
     case CALL_INSN:
@@ -2690,7 +2690,7 @@ eliminate_regs_1 (rtx x, machine_mode mem_mode, rtx insn,
 			       ep->previous_offset * INTVAL (XEXP (x, 1)));
 	    }
 
-      /* ... fall through ...  */
+      /* fall through */
 
     case CALL:
     case COMPARE:
@@ -2737,7 +2737,7 @@ eliminate_regs_1 (rtx x, machine_mode mem_mode, rtx insn,
 	    }
 	}
 
-      /* ... fall through ...  */
+      /* fall through */
 
     case INSN_LIST:
     case INT_LIST:
@@ -5499,7 +5500,7 @@ reload_reg_reaches_end_p (unsigned int regno, int reloadnum)
 
       opnum = reload_n_operands;
 
-      /* ... fall through ...  */
+      /* fall through */
 
     case RELOAD_FOR_OUTPUT:
     case RELOAD_FOR_OUTPUT_ADDRESS:
--- gcc/gcc/rtlanal.c
+++ gcc/gcc/rtlanal.c
@@ -3421,6 +3421,7 @@ commutative_operand_precedence (rtx op)
       /* Then prefer NEG and NOT.  */
       if (code == NEG || code == NOT)
         return 1;
+      /* FALLTHRU */
 
     default:
       return 0;
@@ -4095,7 +4096,7 @@ rtx_cost (rtx x, machine_mode mode, enum rtx_code outer_code,
       factor = GET_MODE_SIZE (mode) / UNITS_PER_WORD;
       if (factor == 0)
 	factor = 1;
-      /* Pass through.  */
+      /* FALLTHRU */
     default:
       total = factor * COSTS_N_INSNS (1);
     }
--- gcc/gcc/sched-rgn.c
+++ gcc/gcc/sched-rgn.c
@@ -2036,6 +2036,7 @@ is_exception_free (rtx_insn *insn, int bb_src, int bb_trg)
       if (is_pfree (insn, bb_src, bb_trg))
 	return 1;
       /* Don't 'break' here: PFREE-candidate is also PRISKY-candidate.  */
+      /* FALLTHRU */
     case PRISKY_CANDIDATE:
       if (!flag_schedule_speculative_load_dangerous
 	  || is_prisky (insn, bb_src, bb_trg))
--- gcc/gcc/simplify-rtx.c
+++ gcc/gcc/simplify-rtx.c
@@ -6256,7 +6256,7 @@ simplify_rtx (const_rtx x)
       if (swap_commutative_operands_p (XEXP (x, 0), XEXP (x, 1)))
 	return simplify_gen_binary (code, mode, XEXP (x, 1), XEXP (x, 0));
 
-      /* Fall through....  */
+      /* Fall through.  */
 
     case RTX_BIN_ARITH:
       return simplify_binary_operation (code, mode, XEXP (x, 0), XEXP (x, 1));
--- gcc/gcc/stor-layout.c
+++ gcc/gcc/stor-layout.c
@@ -398,7 +398,7 @@ int_mode_for_mode (machine_mode mode)
       if (mode == BLKmode)
 	break;
 
-      /* ... fall through ...  */
+      /* fall through */
 
     case MODE_CC:
     default:
--- gcc/gcc/toplev.c
+++ gcc/gcc/toplev.c
@@ -731,7 +731,7 @@ print_to_asm_out_file (print_switch_type type, const char * text)
     case SWITCH_TYPE_DESCRIPTIVE:
       if (ASM_COMMENT_START[0] == 0)
 	prepend_sep = false;
-      /* Drop through.  */
+      /* FALLTHRU */
     case SWITCH_TYPE_PASSED:
     case SWITCH_TYPE_ENABLED:
       if (prepend_sep)
@@ -761,7 +761,7 @@ print_to_stderr (print_switch_type type, const char * text)
     case SWITCH_TYPE_PASSED:
     case SWITCH_TYPE_ENABLED:
       fputc (' ', stderr);
-      /* Drop through.  */
+      /* FALLTHRU */
 
     case SWITCH_TYPE_DESCRIPTIVE:
       fputs (text, stderr);
--- gcc/gcc/tree-cfg.c
+++ gcc/gcc/tree-cfg.c
@@ -5412,7 +5412,7 @@ gimple_verify_flow_info (void)
 	case GIMPLE_CALL:
 	  if (!gimple_call_builtin_p (stmt, BUILT_IN_RETURN))
 	    break;
-	  /* ... fallthru ... */
+	  /* fallthru */
 	case GIMPLE_RETURN:
 	  if (!single_succ_p (bb)
 	      || (single_succ_edge (bb)->flags
--- gcc/gcc/tree-chrec.c
+++ gcc/gcc/tree-chrec.c
@@ -287,6 +287,7 @@ chrec_fold_plus_1 (enum tree_code code, tree type,
 	CASE_CONVERT:
 	  if (tree_contains_chrecs (op1, NULL))
 	    return chrec_dont_know;
+	  /* FALLTHRU */
 
 	default:
 	  if (code == PLUS_EXPR || code == POINTER_PLUS_EXPR)
@@ -304,6 +305,7 @@ chrec_fold_plus_1 (enum tree_code code, tree type,
     CASE_CONVERT:
       if (tree_contains_chrecs (op0, NULL))
 	return chrec_dont_know;
+      /* FALLTHRU */
 
     default:
       switch (TREE_CODE (op1))
@@ -329,6 +331,7 @@ chrec_fold_plus_1 (enum tree_code code, tree type,
 	CASE_CONVERT:
 	  if (tree_contains_chrecs (op1, NULL))
 	    return chrec_dont_know;
+	  /* FALLTHRU */
 
 	default:
 	  {
@@ -423,6 +426,7 @@ chrec_fold_multiply (tree type,
 	CASE_CONVERT:
 	  if (tree_contains_chrecs (op1, NULL))
 	    return chrec_dont_know;
+	  /* FALLTHRU */
 
 	default:
 	  if (integer_onep (op1))
@@ -439,6 +443,7 @@ chrec_fold_multiply (tree type,
     CASE_CONVERT:
       if (tree_contains_chrecs (op0, NULL))
 	return chrec_dont_know;
+      /* FALLTHRU */
 
     default:
       if (integer_onep (op0))
@@ -461,6 +466,7 @@ chrec_fold_multiply (tree type,
 	CASE_CONVERT:
 	  if (tree_contains_chrecs (op1, NULL))
 	    return chrec_dont_know;
+	  /* FALLTHRU */
 
 	default:
 	  if (integer_onep (op1))
@@ -1026,6 +1032,7 @@ evolution_function_is_invariant_rec_p (tree chrec, int loopnum)
       if (!evolution_function_is_invariant_rec_p (TREE_OPERAND (chrec, 1),
 						  loopnum))
 	return false;
+      /* FALLTHRU */
 
     case 1:
       if (!evolution_function_is_invariant_rec_p (TREE_OPERAND (chrec, 0),
@@ -1533,12 +1540,15 @@ for_each_scev_op (tree *scev, bool (*cbck) (tree *, void *), void *data)
     {
     case 3:
       for_each_scev_op (&TREE_OPERAND (*scev, 2), cbck, data);
+      /* FALLTHRU */
 
     case 2:
       for_each_scev_op (&TREE_OPERAND (*scev, 1), cbck, data);
+      /* FALLTHRU */
 
     case 1:
       for_each_scev_op (&TREE_OPERAND (*scev, 0), cbck, data);
+      /* FALLTHRU */
 
     default:
       cbck (scev, data);
--- gcc/gcc/tree-data-ref.c
+++ gcc/gcc/tree-data-ref.c
@@ -1685,6 +1685,7 @@ siv_subscript_p (const_tree chrec_a, const_tree chrec_b)
 	    case POLYNOMIAL_CHREC:
 	      if (CHREC_VARIABLE (chrec_a) != CHREC_VARIABLE (chrec_b))
 		return false;
+	      /* FALLTHRU */
 
 	    default:
 	      return true;
@@ -3890,6 +3891,7 @@ get_references_in_stmt (gimple *stmt, vec<data_ref_loc, va_heap> *references)
 	    if (gimple_call_lhs (stmt) == NULL_TREE)
 	      break;
 	    ref.is_read = true;
+	    /* FALLTHRU */
 	  case IFN_MASK_STORE:
 	    ptr = build_int_cst (TREE_TYPE (gimple_call_arg (stmt, 1)), 0);
 	    align = tree_to_shwi (gimple_call_arg (stmt, 1));
--- gcc/gcc/tree.c
+++ gcc/gcc/tree.c
@@ -3727,7 +3727,7 @@ find_placeholder_in_expr (tree exp, vec<tree> *refs)
 	    break;
 	  }
 
-        /* Fall through...  */
+        /* Fall through.  */
 
       case tcc_exceptional:
       case tcc_unary:
@@ -3816,7 +3816,7 @@ substitute_in_expr (tree exp, tree f, tree r)
 	if (exp == f)
 	  return r;
 
-        /* Fall through...  */
+        /* Fall through.  */
 
       case tcc_exceptional:
       case tcc_unary:
@@ -7027,7 +7027,7 @@ type_cache_hasher::equal (type_hash *a, type_hash *b)
 				   TYPE_VALUES (b->type))))
 	return 0;
 
-      /* ... fall through ... */
+      /* fall through */
 
     case INTEGER_TYPE:
     case REAL_TYPE:
@@ -11564,7 +11564,7 @@ walk_type_fields (tree type, walk_tree_fn func, void *data,
 	  break;
 	}
 
-      /* ... fall through ... */
+      /* fall through */
 
     case COMPLEX_TYPE:
       WALK_SUBTREE (TREE_TYPE (type));
--- gcc/gcc/var-tracking.c
+++ gcc/gcc/var-tracking.c
@@ -1056,6 +1056,7 @@ adjust_mems (rtx loc, const_rtx old_rtx, void *data)
 					 ? GET_MODE_SIZE (amd->mem_mode)
 					 : -GET_MODE_SIZE (amd->mem_mode),
 					 GET_MODE (loc)));
+      /* FALLTHRU */
     case POST_INC:
     case POST_DEC:
       if (addr == loc)
@@ -1076,6 +1077,7 @@ adjust_mems (rtx loc, const_rtx old_rtx, void *data)
       return addr;
     case PRE_MODIFY:
       addr = XEXP (loc, 1);
+      /* FALLTHRU */
     case POST_MODIFY:
       if (addr == loc)
 	addr = XEXP (loc, 0);
@@ -3148,7 +3150,7 @@ set_dv_changed (decl_or_value dv, bool newv)
     case ONEPART_DEXPR:
       if (newv)
 	NO_LOC_P (DECL_RTL_KNOWN_SET (dv_as_decl (dv))) = false;
-      /* Fall through...  */
+      /* Fall through.  */
 
     default:
       DECL_CHANGED (dv_as_decl (dv)) = newv;
--- gcc/gcc/varasm.c
+++ gcc/gcc/varasm.c
@@ -589,6 +589,7 @@ default_function_section (tree decl, enum node_frequency freq,
            these ELF section.  */
         if (!in_lto_p || !flag_profile_values)
           return get_named_text_section (decl, ".text.hot", NULL);
+	/* FALLTHRU */
       default:
 	return NULL;
     }
--- gcc/libcpp/lex.c
+++ gcc/libcpp/lex.c
@@ -610,6 +610,7 @@ search_line_fast (const uchar *s, const uchar *end ATTRIBUTE_UNUSED)
 	if (l != 0)
 	  break;
 	s += sizeof(unsigned long);
+	/* FALLTHRU */
       case 2:
 	l = u.l[i++];
 	if (l != 0)
@@ -2717,6 +2718,7 @@ _cpp_lex_direct (cpp_reader *pfile)
 	  }
 	buffer->cur++;
       }
+      /* FALLTHRU */
 
     default:
       create_literal (pfile, result, buffer->cur - 1, 1, CPP_OTHER);
@@ -3322,7 +3324,7 @@ cpp_token_val_index (const cpp_token *tok)
 	return CPP_TOKEN_FLD_SOURCE;
       else if (tok->type == CPP_PRAGMA)
 	return CPP_TOKEN_FLD_PRAGMA;
-      /* else fall through */
+      /* fall through */
     default:
       return CPP_TOKEN_FLD_NONE;
     }
--- gcc/libcpp/macro.c
+++ gcc/libcpp/macro.c
@@ -2886,6 +2886,7 @@ parse_params (cpp_reader *pfile, cpp_macro *macro)
 	    return true;
 
 	  /* Fall through to pick up the error.  */
+	  /* FALLTHRU */
 	case CPP_COMMA:
 	  if (!prev_ident)
 	    {
--- gcc/libcpp/pch.c
+++ gcc/libcpp/pch.c
@@ -230,7 +230,7 @@ count_defs (cpp_reader *pfile ATTRIBUTE_UNUSED, cpp_hashnode *hn, void *ss_p)
       if (hn->flags & NODE_BUILTIN)
 	return 1;
 
-      /* else fall through.  */
+      /* fall through.  */
 
     case NT_VOID:
       {
@@ -269,7 +269,7 @@ write_defs (cpp_reader *pfile ATTRIBUTE_UNUSED, cpp_hashnode *hn, void *ss_p)
       if (hn->flags & NODE_BUILTIN)
 	return 1;
 
-      /* else fall through.  */
+      /* fall through.  */
 
     case NT_VOID:
       {
--- gcc/libiberty/cp-demangle.c
+++ gcc/libiberty/cp-demangle.c
@@ -5777,11 +5777,13 @@ d_print_mod (struct d_print_info *dpi, int options,
     case DEMANGLE_COMPONENT_REFERENCE_THIS:
       /* For the ref-qualifier, put a space before the &.  */
       d_append_char (dpi, ' ');
+      /* FALLTHRU */
     case DEMANGLE_COMPONENT_REFERENCE:
       d_append_char (dpi, '&');
       return;
     case DEMANGLE_COMPONENT_RVALUE_REFERENCE_THIS:
       d_append_char (dpi, ' ');
+      /* FALLTHRU */
     case DEMANGLE_COMPONENT_RVALUE_REFERENCE:
       d_append_string (dpi, "&&");
       return;
