Re: [PATCH] configure: Disable -Wtautological-type-limit-compare

[Richard Henderson]

On 6/5/20 8:53 AM, Alex Bennée wrote:
> 
> Richard Henderson <richard.henderson@linaro.org> writes:
> 
>> Clang 10 enables this by default with -Wtype-limit.
>>
>> All of the instances flagged by this Werror so far have been
>> cases in which we really do want the compiler to optimize away
>> the test completely.  Disabling the warning will avoid having
>> to add ifdefs to work around this.
>>
>> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
>> ---
>>  configure | 2 ++
>>  1 file changed, 2 insertions(+)
>>
>> diff --git a/configure b/configure
>> index f087d2bcd1..693f01327f 100755
>> --- a/configure
>> +++ b/configure
>> @@ -2009,6 +2009,8 @@ gcc_flags="-Wno-missing-include-dirs -Wempty-body 
>> -Wnested-externs $gcc_flags"
>>  gcc_flags="-Wendif-labels -Wno-shift-negative-value $gcc_flags"
>>  gcc_flags="-Wno-initializer-overrides -Wexpansion-to-defined $gcc_flags"
>>  gcc_flags="-Wno-string-plus-int -Wno-typedef-redefinition $gcc_flags"
>> +gcc_flags="$gcc_flags -Wno-tautological-type-limit-compare"
>> +
> 
> nit: the pattern is reversed compared to the previous lines (foo $gcc_flags)

Not a nit.  The -Wno- must follow -Wtype-limit, or -Wtype-limit will turn it
back on.


r~

> 
> I had exactly the same patch in my local tree but it wasn't enough for
> clang-9 which I was using for a sanitiser build. I ended up
> having to apply --disable-werrror to the configuration.
> 
> Anyway:
> 
> Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
>