[PATCH] Support constant expressions, including non-type template parameters, in pragma loop hints

[Aaron Ballman]

On Fri, Aug 1, 2014 at 3:06 PM, Tyler Nowicki <tnowicki at apple.com> wrote:
>>> +  SmallVector<Token, 1> ValueList;
>>> +  // Read constant expression.
>>> +  while (Tok.isNot(tok::r_paren) && Tok.isNot(tok::eod)) {
>>> +    ValueList.push_back(Tok);
>>> +    PP.Lex(Tok);
>>
>> I don't think this is correct -- it won't handle constant expressions
>> involving parentheses properly. Eg)
>>
>> #pragma unroll((2+2)+4)
>>
>> It produces:
>> E:\Aaron Ballman\Desktop\test2.cpp:9:21: warning: extra tokens at end
>> of '#pragma unroll' - ignored
>> #pragma unroll((2+2)+4)
>>
>> So that should be fixed, and you should have a test for it as well.
>
> Oops, you are right. How about we do this incrementally? We can put this patch in now and I'll follow up with better parsing. I’ll be able work on this in a couple of weeks.
>
> I think we need to use the BalancedDelimiterTracker to resolve this issue.

If you put in a FIXME with the code, and a commented-out test case
with a FIXME, I can live with that. I also agree that this code should
be using the BalancedDelimiterTracker. It will simplify a bit of the
code when you switch over to it.

The rest of the patch LGTM, but I would also wait for Richard to
comment on the patch just in case (he's more familiar with the
constant expression stuff than I am).

Also, don't forget to move the test cases to their appropriate directories. ;-)

~Aaron