Define __FINITE_MATH_ONLY__ based on -ffast-math and -ffinite-math-only.

This macro was being unconditionally set to zero, preceded by a FIXME comment.
This fixes <rdar://problem/11845441>.  Patch by Michael Gottesman!

llvm-svn: 160491

clang/lib/Frontend/CompilerInvocation.cpp

@@ -2100,6 +2100,7 @@ static void ParseLangArgs(LangOptions &Opts, ArgList &Args, InputKind IK,
   Opts.NoInlineDefine = !Opt || Args.hasArg(OPT_fno_inline);
 
   Opts.FastMath = Args.hasArg(OPT_ffast_math);
+  Opts.FiniteMathOnly = Args.hasArg(OPT_ffinite_math_only);
 
   unsigned SSP = Args.getLastArgIntValue(OPT_stack_protector, 0, Diags);
   switch (SSP) {