[PATCH] D28126: [MemDep] Handle gep with zeros for invariant.group

[Piotr Padlewski via Phabricator via llvm-commits]

Prazek added inline comments.


================
Comment at: lib/Analysis/MemoryDependenceAnalysis.cpp:383-384
+      // U = bitcast Ptr  ||  U = getelementptr Ptr, 0, 0...
+      auto *BCI = dyn_cast<BitCastInst>(U);
+      auto *GEP = dyn_cast<GetElementPtrInst>(U);
+      if (BCI || (GEP && GEP->hasAllZeroIndices())) {
----------------
Prazek wrote:
> chandlerc wrote:
> > It would be nice to avoid going through the type lookup machinery twice here.
> Code elegance your concern here right?
> I can put it in ifs like
> 
>   if (isa<BitCastInst>(U)) {
>     TryInsertToQueue(U);
>     continue;
>   }
>   if (auto *GEP = dyn_cast<GetElementPtr>(U)) {
>     if(GEP->hasAllZeroIndices())
>       TryInsertToQueue(U);
>     continue;
>   }
> 
> I am not sure if it will be cleaner (specially because of nested if)
> 
>   
>   

if (auto *GEP = dyn_cast<GetElementPtr>(U); GEP && GEP->hasAllZeroIndices()) {
  TryInsertToQueue(U);
  continue;
}

This is exactly why I really would love to use C++17 in LLVM :)


https://reviews.llvm.org/D28126