AMDGPU/SI: Update LiveIntervals during SIFixSGPRLiveRanges

[arsenm]

Summary

Does not mark SlotIndexes as reserved, although I think that might be OK.

LiveVariables still need to be handled.

[arsenm]

Use .getRegSlot()

[• tstellarAMD]

LGTM.

[arsenm]

r245133

lib/Target/AMDGPU/SIFixSGPRLiveRanges.cpp

public:
   const char *getPassName() const override {
     return "SI Fix SGPR live ranges";
   }
 
   void getAnalysisUsage(AnalysisUsage &AU) const override {
     AU.addRequired<LiveIntervals>();
     AU.addRequired<MachinePostDominatorTree>();
     AU.setPreservesCFG();
+
+    //AU.addPreserved<SlotIndexes>(); // XXX - This might be OK
+    AU.addPreserved<LiveIntervals>();
+
     MachineFunctionPass::getAnalysisUsage(AU);
   }
 };
 
 } // End anonymous namespace.
 
 INITIALIZE_PASS_BEGIN(SIFixSGPRLiveRanges, DEBUG_TYPE,
                       "SI Fix SGPR Live Ranges", false, false)
for (std::pair<unsigned, LiveRange*> RegLR : SGPRLiveRanges) {
       DEBUG(dbgs() << "Possible SGPR conflict detected for "
             << PrintReg(Reg, TRI, 0) <<  " in " << *LR
             << " BB#" << SuccA->getNumber() << ", BB#"
             << SuccB->getNumber()
             << " with NCD = BB#" << NCD->getNumber() << '\n');
 
       // FIXME: Need to figure out how to update LiveRange here so this pass
       // will be able to preserve LiveInterval analysis.
+      MachineInstr *NCDSGPRUse =
         BuildMI(*NCD, NCD->getFirstNonPHI(), DebugLoc(),
                 TII->get(AMDGPU::SGPR_USE))
-              .addReg(Reg, RegState::Implicit);
-      DEBUG(NCD->getFirstNonPHI()->dump());
+
+      SlotIndex SI = LIS->InsertMachineInstrInMaps(NCDSGPRUse);
+      LIS->extendToIndices(*LR, SI.getRegSlot());
+
+      DEBUG(NCDSGPRUse->dump());
     }
   }
 
   return false;
 }