[NFC][AMDGPU] assert we've found a value before use

[ldrumm]

Summary

The sync pipeline should always contain the candidate ID. If it doesn't something's gone awry. assert on that.

[jrbyrnes]

llvm/lib/Target/AMDGPU/AMDGPUIGroupLP.cpp

597

Can we convert these into std::find_if?

SchedGroup *Match = std::find_if(
    SyncPipeline.begin(), SyncPipeline.end(),
    [&CandSGID](SchedGroup SG) { return SG.getSGID() == CandSGID; });
assert(Match != SyncPipeline.end());

[ldrumm]

Use find_if instead of a search loop.

[ldrumm]

llvm/lib/Target/AMDGPU/AMDGPUIGroupLP.cpp

597

Yeah. That'd work too. We can also use llvm::find_if, and capture CandSGID by value.
Updated

[jrbyrnes]

Thanks, LGTM

llvm/lib/Target/AMDGPU/AMDGPUIGroupLP.cpp

void PipelineSolver::populateReadyList(
     SmallVectorImpl<std::pair<int, int>> &ReadyList, T I, T E) {
   SUToCandSGsPair CurrSU = PipelineInstrs[CurrSyncGroupIdx][CurrConflInstNo];
   auto SyncPipeline = CurrPipeline[CurrSyncGroupIdx];
   assert(CurrSU.second.size() >= 1);
 
   for (; I != E; ++I) {
     std::vector<std::pair<SUnit *, SUnit *>> AddedEdges;
     int CandSGID = *I;
-    SchedGroup *Match;
+    SchedGroup *Match = nullptr;
     for (auto &SG : SyncPipeline) {
       if (SG.getSGID() == CandSGID)
         Match = &SG;
     }
+    assert(Match);
 
     if (UseCostHeur) {
       if (Match->isFull()) {
         ReadyList.push_back(std::pair(*I, MissPenalty));
         continue;
       }
 
       int TempCost = addEdges(SyncPipeline, CurrSU.first, CandSGID, AddedEdges);
void PipelineSolver::greedyFind(
 
   // Since we have added the potential SchedGroups from bottom up, but
   // traversed the DAG from top down, parse over the groups from last to
   // first. If we fail to do this for the greedy algorithm, the solution will
   // likely not be good in more complex cases.
   for (; I != E; ++I) {
     std::vector<std::pair<SUnit *, SUnit *>> AddedEdges;
     int CandSGID = *I;
-    SchedGroup *Match;
+    SchedGroup *Match = nullptr;
     for (auto &SG : SyncPipeline) {
       if (SG.getSGID() == CandSGID)
         Match = &SG;
     }
+    assert(Match);
 
     LLVM_DEBUG(dbgs() << "Trying SGID # " << CandSGID << " with Mask "
                       << (int)Match->getMask() << "\n");
 
     if (Match->isFull()) {
       LLVM_DEBUG(dbgs() << "SGID # " << CandSGID << " is full\n");
       continue;
     }