[LLVMdev] Compiler error: LoopStrengthReduce.cpp

[OvermindDL1]

On Tue, May 12, 2009 at 6:26 PM, Dale Johannesen <dalej at apple.com> wrote:
>
> On May 12, 2009, at 5:01 PMPDT, OvermindDL1 wrote:
>
>> On Tue, May 12, 2009 at 5:01 PM, Dale Johannesen <dalej at apple.com>
>> wrote:
>>>
>>> On May 12, 2009, at 3:09 PMPDT, OvermindDL1 wrote:
>>>
>>>> The error given:
>>>>
>>>> ..\..\..\..\trunk\lib\Transforms\Scalar
>>>> \LoopStrengthReduce.cpp(1016) :
>>>> error C2668: 'abs' : ambiguous call to overloaded function
>>>>
>>>> It should be rather obvious from the message.  The error is in
>>>> LoopStrengthReduce.cpp on line 1016:
>>>>          (unsigned(abs(SInt)) < SSInt || (SInt % SSInt) != 0))
>>>>
>>>>> From looking at the code and what it looks like it should be
>>>>> doing, I
>>>> cannot really tell whether it should use the 32-bit override, or
>>>> if it
>>>> should use something like the long double override, considering this
>>>> is a 64-bit integer.
>>>
>>> It should be a 64-bit integer abs, although gcc seems to be
>>> generating
>>> code for 32-bit integer (which, in this code, would give the expected
>>> answer in any reasonable example).  There are 4 occurrences of this
>>> usage in that file (with 3 different authors) so I think we need to
>>> write one; apparently nobody realized there wasn't one in the
>>> standard
>>> libraries (I didn't either).
>>
>> Ah, I mentioned it before, but was told that the error was not
>> appearing with GCC and they were busy at the time, so I just have been
>> inserting an (int) in my version ever since, but it reappeared when I
>> synced back to trunk today since I deleted my version, and I have just
>> been reporting random things I have been crossing.  I noticed a few
>> other warnings about struct/class forward declarations as well, but
>> did not catch them in time, I intend to look through it closely later
>> and report more.
>>
>> So, for now, just keep using (int) in my version until it is fixed
>> in trunk?
>
> I checked in a fix.

Also, IndVarSimplify.cpp has the same problem, only one abs usage in
it, line 700:
  if (Max.getZExtValue() > static_cast<uint64_t>(abs(intEV - intIV)))
Following your style change:
  if (Max.getZExtValue() > static_cast<uint64_t>(abs64(intEV - intIV)))

Also, why make an abs64, why not just override abs with 64 bit parameters?