C++1y: Add a step limit to constexpr evaluation, to catch runaway loops.

llvm-svn: 181388

clang/lib/Frontend/CompilerInvocation.cpp

@@ -1251,6 +1251,8 @@ static void ParseLangArgs(LangOptions &Opts, ArgList &Args, InputKind IK,
                                                     Diags);
   Opts.ConstexprCallDepth = Args.getLastArgIntValue(OPT_fconstexpr_depth, 512,
                                                     Diags);
+  Opts.ConstexprStepLimit = Args.getLastArgIntValue(OPT_fconstexpr_steps,
+                                                    1048576, Diags);
   Opts.BracketDepth = Args.getLastArgIntValue(OPT_fbracket_depth, 256, Diags);
   Opts.DelayedTemplateParsing = Args.hasArg(OPT_fdelayed_template_parsing);
   Opts.NumLargeByValueCopy = Args.getLastArgIntValue(OPT_Wlarge_by_value_copy_EQ,