[llvm] r215888 - Silencing an MSVC warning about loop variable conflicting with a variable from an outer scope. NFC.

[David Blaikie]

On Mon, Aug 18, 2014 at 7:33 AM, Aaron Ballman <aaron at aaronballman.com> wrote:
> On Mon, Aug 18, 2014 at 10:18 AM, David Blaikie <dblaikie at gmail.com> wrote:
>> On Mon, Aug 18, 2014 at 4:51 AM, Aaron Ballman <aaron at aaronballman.com> wrote:
>>> Author: aaronballman
>>> Date: Mon Aug 18 06:51:41 2014
>>> New Revision: 215888
>>>
>>> URL: http://llvm.org/viewvc/llvm-project?rev=215888&view=rev
>>> Log:
>>> Silencing an MSVC warning about loop variable conflicting with a variable from an outer scope. NFC.
>>
>> Sorry if this gets a bit repetitious (I ask this about every non-clang
>> warning we make code fixes for) - should we just disable this MSVC
>> warning in LLVM's build system?
>
> I don't think we should; MSVC only seems to warn on code that is truly
> strange. In this case, the loop variable was unsigned, but the
> outer-scope variable of type SDNode * was being used within the loop.

I'm not sure I follow - there's no mention of "N" inside the loop that
would appear to be using the outer-scope variable (how could it -
scoping rules would pick the closest scoped "N")?

>> Either that, or we could turn on Clang's -Wshadow to catch these in
>> clang builds too, if it's a thing we want to catch/fix.
>
> If Clang isn't overly noisy, I think I would prefer that.

It looks like even the case you just fixed would meet Clang's bar for
"false positive" - I don't see the bug here, nor why this case of
shadowing is particularly more buggy than any other (correct) case.
The "N" accessed looks like it's entirely the one the author intended.

- David