r193887 - Disable -Wtautological-constant-out-of-range-compare in template instantiations.

[Richard Trieu]

Woot!  ~3 year old bug closed!


On Fri, Nov 1, 2013 at 2:54 PM, Richard Smith <richard at metafoo.co.uk> wrote:

> Maybe you want to close PR8682? =)
>
>
> On Fri, Nov 1, 2013 at 2:19 PM, Richard Trieu <rtrieu at google.com> wrote:
>
>> Author: rtrieu
>> Date: Fri Nov  1 16:19:43 2013
>> New Revision: 193887
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=193887&view=rev
>> Log:
>> Disable -Wtautological-constant-out-of-range-compare in template
>> instantiations.
>>
>> Modified:
>>     cfe/trunk/lib/Sema/SemaChecking.cpp
>>     cfe/trunk/test/SemaCXX/compare.cpp
>>
>> Modified: cfe/trunk/lib/Sema/SemaChecking.cpp
>> URL:
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaChecking.cpp?rev=193887&r1=193886&r2=193887&view=diff
>>
>> ==============================================================================
>> --- cfe/trunk/lib/Sema/SemaChecking.cpp (original)
>> +++ cfe/trunk/lib/Sema/SemaChecking.cpp Fri Nov  1 16:19:43 2013
>> @@ -4806,6 +4806,10 @@ static void DiagnoseOutOfRangeComparison
>>                                           Expr *Constant, Expr *Other,
>>                                           llvm::APSInt Value,
>>                                           bool RhsConstant) {
>> +  // Disable warning in template instantiations.
>> +  if (!S.ActiveTemplateInstantiations.empty())
>> +    return;
>> +
>>    // 0 values are handled later by CheckTrivialUnsignedComparison().
>>    if (Value == 0)
>>      return;
>>
>> Modified: cfe/trunk/test/SemaCXX/compare.cpp
>> URL:
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/compare.cpp?rev=193887&r1=193886&r2=193887&view=diff
>>
>> ==============================================================================
>> --- cfe/trunk/test/SemaCXX/compare.cpp (original)
>> +++ cfe/trunk/test/SemaCXX/compare.cpp Fri Nov  1 16:19:43 2013
>> @@ -355,3 +355,29 @@ void test9(int x) {
>>    };
>>    (void)((E)x == 1);
>>  }
>> +
>> +namespace templates {
>> +  template<class T> T max();
>> +
>> +  template<> constexpr int max<int>() { return 2147483647; };
>> +
>> +  template<typename T>
>> +  bool less_than_max(short num, T value) {
>> +    const T vmax = max<T>();
>> +    return (vmax >= num);  // no warning
>> +  }
>> +
>> +  template<typename T>
>> +  bool less_than_max(short num) {
>> +    // This should trigger one warning on the template pattern, and not a
>> +    // warning per specialization.
>> +    return num < max<int>();  // expected-warning{{comparison of
>> constant 2147483647 with expression of type 'short' is always true}}
>> +  }
>> +
>> +  void test10(short num, int x) {
>> +    less_than_max(num, x);
>> +    less_than_max<int>(num);
>> +    less_than_max<long>(num);
>> +    less_than_max<short>(num);
>> +  }
>> +}
>>
>>
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>>
>
>
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