[cfe-commits] r125640 - in /cfe/trunk: include/clang/Basic/DiagnosticSemaKinds.td include/clang/Sema/Sema.h lib/Sema/SemaChecking.cpp lib/Sema/SemaExpr.cpp test/Analysis/out-of-bounds.c test/Sema/array-bounds.c

[Chris Lattner]

On Feb 17, 2011, at 9:11 AM, Ted Kremenek wrote:

>> This breaks the Chrome build, where we have some code like this:
>> 
>> template <bool extendArray>
>> void myFunc() {
>>    int arr[3 + (extendArray ? 1 : 0)];
>> 
>>    if (extendArray)
>>        arr[3] = 42;
>> }
>> 
>> You can always explicitly specialize myFunc for true and false. I think it would make the resulting code strictly more clean. I'm kinda glad the warning fires on this type of construct.
> 
> While I agree with that assessment, I'm not certain why we are getting a ConstantArrayType whose size is 3 if the only instantiation of myFunc is for extendArray = false.  I'd like to know *why* the warning is firing here.

When extendArray is false, the instantiated code is:

>> template <bool extendArray>
>> void myFunc() {
>>    int arr[3 ];
>> 
>>    if (false)
>>        arr[3] = 42;
>> }

so it's the same as the other case.  I thought we already had some infrastructure for disabling warnings in unreachable code?

-Chris
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