[cfe-dev] error: unknown argument: '-ffoo' => reason ?

[Sylvestre Ledru]

On 22/01/2014 02:45, Joerg Sonnenberger wrote:
> On Tue, Jan 21, 2014 at 10:27:08PM -0500, Rafael Espíndola wrote:
>>>> We do try to ignore GCC options that are safe to ignore, so a patch
>>>> ignoring the ones that are causing you trouble is probably fine.
>>>>
>>> OK. Thanks for the information.
>>>
>>> There are quite some items with their occurrences:
>>>       2 '-falign-jumps=2'
>>>       2 '-fcheck-new'
>>>      33 '-fexcess-precision=standard'
>>>       2 '-fforce-addr'
>>>       2 '-ffriend-injection'
>>>       2 '-fgcse-after-reload'
>>>       6 '-finline-limit='
>>>       2 '-finput-charset=UTF-8'
>>>       6 '-fno-check-new'
>>>      40 '-fno-defer-pop'
>>>       4 '-fno-delete-null-pointer-checks'
>>>       1 '-fno-implement-inlines'
>>>       1 '-fno-tree-ter'
>>>      11 '-fno-tree-vrp'
>>>       4 '-frename-registers'
>>>       2 '-frerun-loop-opt'
>>>       2 '-fsingle-precision-constant'
>>>       2 '-fstack-check'
>>>       2 '-fuse-linker-plugin'
>>>       2 '-fvar-tracking'
>>>       7 '-gnatea'
>>>       2 '-gnatec=foo'
>>>       2 '-malign-double'
>>>       2 '-malign-jumps=1'
>>>       4 '-print-multiarch'
>>>       4 '-z'
>>>
>>> Do you think I should ignore (all/most) them?
>> At least all the ones that just enable or disable a pass. Things like
>> -malign-double would probably turn a build error into a miscompilation
>> if ignored, so probably not.
> I disagree that we should be adding random "disable pass" options. It
> just doesn't make sense and most of them shouldn't have been applied
> unconditionally in first place as they are workarounds for optimizer
> bugs in specific gcc versions. From the list:
> -  -fexcess-precision must not be dropped silently,
> -  -fno-check-new / -fcheck-new was discussed before, language lawyers
>    can comment
> -  -finput-charset=UTF-8 would be safe to drop as it is the default
> -  -fsingle-precision-constant potentially changes behavior
> -  -fno-defer-pop was typically used without good reason, but custom asm
>    parsers might depend on it, so no.
> -  -z should likely be fixed to be -Wl,-z
>
> I would not change anything except maybe -finput-charset=UTF-8.
OK. I will give it a try with your list then.

Thanks for taking the time,
Sylvestre