r264008 - [sema] [CUDA] Use std algorithms in EraseUnwantedCUDAMatchesImpl.

[Justin Lebar via cfe-commits]

Interestingly all the clang tests pass with that whole line commented
out.  So something *really* seems missing here.

Thank you for finding this.

On Thu, Jun 30, 2016 at 5:08 AM, Benjamin Kramer <benny.kra at gmail.com> wrote:
> On Tue, Mar 22, 2016 at 1:09 AM, Justin Lebar via cfe-commits
> <cfe-commits at lists.llvm.org> wrote:
>> Author: jlebar
>> Date: Mon Mar 21 19:09:25 2016
>> New Revision: 264008
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=264008&view=rev
>> Log:
>> [sema] [CUDA] Use std algorithms in EraseUnwantedCUDAMatchesImpl.
>>
>> Summary: NFC
>>
>> Reviewers: tra
>>
>> Subscribers: cfe-commits
>>
>> Differential Revision: http://reviews.llvm.org/D18327
>>
>> Modified:
>>     cfe/trunk/lib/Sema/SemaCUDA.cpp
>>
>> Modified: cfe/trunk/lib/Sema/SemaCUDA.cpp
>> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaCUDA.cpp?rev=264008&r1=264007&r2=264008&view=diff
>> ==============================================================================
>> --- cfe/trunk/lib/Sema/SemaCUDA.cpp (original)
>> +++ cfe/trunk/lib/Sema/SemaCUDA.cpp Mon Mar 21 19:09:25 2016
>> @@ -210,31 +210,28 @@ bool Sema::CheckCUDATarget(const Functio
>>    return false;
>>  }
>>
>> -template <typename T, typename FetchDeclFn>
>> -static void EraseUnwantedCUDAMatchesImpl(Sema &S, const FunctionDecl *Caller,
>> -                                         llvm::SmallVectorImpl<T> &Matches,
>> -                                         FetchDeclFn FetchDecl) {
>> +template <typename T>
>> +static void EraseUnwantedCUDAMatchesImpl(
>> +    Sema &S, const FunctionDecl *Caller, llvm::SmallVectorImpl<T> &Matches,
>> +    std::function<const FunctionDecl *(const T &)> FetchDecl) {
>>    assert(S.getLangOpts().CUDATargetOverloads &&
>>           "Should not be called w/o enabled target overloads.");
>>    if (Matches.size() <= 1)
>>      return;
>>
>> +  // Gets the CUDA function preference for a call from Caller to Match.
>> +  auto GetCFP = [&](const T &Match) {
>> +    return S.IdentifyCUDAPreference(Caller, FetchDecl(Match));
>> +  };
>> +
>>    // Find the best call preference among the functions in Matches.
>> -  Sema::CUDAFunctionPreference P, BestCFP = Sema::CFP_Never;
>> -  for (auto const &Match : Matches) {
>> -    P = S.IdentifyCUDAPreference(Caller, FetchDecl(Match));
>> -    if (P > BestCFP)
>> -      BestCFP = P;
>> -  }
>> +  Sema::CUDAFunctionPreference BestCFP = GetCFP(*std::max_element(
>> +      Matches.begin(), Matches.end(),
>> +      [&](const T &M1, const T &M2) { return GetCFP(M1) < GetCFP(M2); }));
>>
>>    // Erase all functions with lower priority.
>> -  for (unsigned I = 0, N = Matches.size(); I != N;)
>> -    if (S.IdentifyCUDAPreference(Caller, FetchDecl(Matches[I])) < BestCFP) {
>> -      Matches[I] = Matches[--N];
>> -      Matches.resize(N);
>> -    } else {
>> -      ++I;
>> -    }
>> +  Matches.erase(llvm::remove_if(
>> +      Matches, [&](const T &Match) { return GetCFP(Match) < BestCFP; }));
>
> This is the single-element form of SmallVector::erase, so it won't
> remove ALL functions with lower priority. I sense a lack of test case
> here.
>
>>  }
>>
>>  void Sema::EraseUnwantedCUDAMatches(const FunctionDecl *Caller,
>>
>>
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