[PATCH] D46928: implantation example for new AliasAnalysis functions (getAddressesDistance + ModRefSameBuffer)

[Atheel Massalha via Phabricator via llvm-commits]

atheel.ma added a comment.

The use is inside a target specific function:

    for (MachineMemOperand *MMOa : MIa.memoperands()) {
      for (MachineMemOperand *MMOb : MIb.memoperands()) {
        // need to handle different bases cases only, otherwise alias will catch
        // it.
        const Value *Va = MMOa->getValue();
        const Value *Vb = MMOb->getValue();
        const PseudoSourceValue *Pa = MMOa->getPseudoValue();
        const PseudoSourceValue *Pb = MMOb->getPseudoValue();
  
        if (Va && Vb) {
          // Ask alias analysis (if there's one available) what's going on if
          // we have access to IR values.
          assert(!Pa && !Pb && "IR vs pseudo value inconsistency");
          uint64_t Sizea = MMOa->getSize();
          uint64_t Sizeb = MMOb->getSize();
  
          // vpld has sometimes UnknownSize
          if ((!CII->isUsingAllBanks(MIa) && !CII->isUsingAllBanks(MIb)) &&
              (MMOa->getSize() == MemoryLocation::UnknownSize ||
               MMOb->getSize() == MemoryLocation::UnknownSize)) {
            continue;
          }
  
          MemoryLocation Loca = MemoryLocation(Va, Sizea, MMOa->getAAInfo());
          MemoryLocation Locb = MemoryLocation(Vb, Sizeb, MMOb->getAAInfo());
  		int64_t ptr1Offset = MMOa->getPointerInfo().Offset;
  		int64_t ptr2Offset = MMOb->getPointerInfo().Offset;
          if (AA->ModRefSameBuffer(Loca, ptr1Offset, Locb, ptr2Offset)) {
  
  			Optional<int64_t> dis = AA->getAddressesDistance(Loca,
  				ptr1Offset, Locb, ptr2Offset);
  
            if ((CII->isUsingAllBanks(MIa) || CII->isUsingAllBanks(MIb))) {
              return true;
            }
            // need to take care with dis<0 *dis%64 => ((*dis%64)+64)%64
            if (dis != None && ((*dis > 0 && Sizeb > (*dis % 64)) ||
                                (*dis < 0 && Sizea > ((*dis % 64) + 64) % 64))) {
              return true;
            }
          }
        }
      }
    }


Repository:
  rL LLVM

https://reviews.llvm.org/D46928