[PATCH] D152066: The LaneMask of Phi-Def LiveRange should be the union of subranges' LaneMask in which the VNI is live.

[michael_zhang via Phabricator via llvm-commits]

Michael-Zhang-21 created this revision.
Herald added subscribers: tpr, hiraditya, qcolombet, MatzeB.
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Michael-Zhang-21 requested review of this revision.
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Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D152066

Files:
  llvm/lib/CodeGen/RegisterCoalescer.cpp


Index: llvm/lib/CodeGen/RegisterCoalescer.cpp
===================================================================
--- llvm/lib/CodeGen/RegisterCoalescer.cpp
+++ llvm/lib/CodeGen/RegisterCoalescer.cpp
@@ -2477,8 +2477,11 @@
           ValueIn = LRQ.valueIn();
           continue;
         }
-        if (LRQ.valueIn() && ValueIn != LRQ.valueIn())
+        if (LRQ.valueIn() && ValueIn != LRQ.valueIn()) {
+          VNI = LRQ.valueIn();
+          TrackReg = SrcReg;
           return std::make_pair(VNI, TrackReg);
+        }
       }
     }
     if (ValueIn == nullptr) {
@@ -2536,6 +2539,16 @@
     // Conservatively assume that all lanes in a PHI are valid.
     LaneBitmask Lanes = SubRangeJoin ? LaneBitmask::getLane(0)
                                      : TRI->getSubRegIndexLaneMask(SubIdx);
+    if (!SubRangeJoin && LIS->getInterval(Reg).hasSubRanges()) {
+      Lanes = LaneBitmask::getNone();
+      for(auto subrangeIt = LIS->getInterval(Reg).subrange_begin();
+          subrangeIt != LIS->getInterval(Reg).subrange_end();
+          subrangeIt++){
+        if (subrangeIt->liveAt(VNI->def)) {
+          Lanes |= subrangeIt->LaneMask;
+        }
+      }
+    }
     V.ValidLanes = V.WriteLanes = Lanes;
   } else {
     DefMI = Indexes->getInstructionFromIndex(VNI->def);


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