C++ PATCH for c++/51827 (mangling error with PCH and LTO)

[Richard Guenther]

On Tue, Jan 17, 2012 at 2:23 PM, Diego Novillo <dnovillo@google.com> wrote:
> On Tue, Jan 17, 2012 at 04:35, Richard Guenther
> <richard.guenther@gmail.com> wrote:
>
>> +  /* Disable LTO output when outputting a precompiled header.  */
>> +  if (pch_file && flag_lto)
>> +    {
>> +      flag_lto = 0;
>> +      flag_generate_lto = 0;
>> +    }
>> +
>
> Emit a warning when you do this?

Well, I'd say peoples Makefiles may not strip -flto properly here (you need to
pass optimization level for example), so I'm not sure that would be good QOI.

> I think we should issue a diagnostic about the combination of these
> two flags.  Silent ignorance would lead to false user expectations
> and supposed "bug" reports, if not confusion.

I'm not sure what "expectation" there would be?

OTOH the bug is fixed by Jason, so we can just do nothing.

Richard.