Process legalization of 64-bit moves on VC

backend side

Author: skachkov-intel

IGC/VectorCompiler/lib/GenXCodeGen/GenXDeadVectorRemoval.cpp

@@ -448,6 +448,21 @@ void GenXDeadVectorRemoval::processRdRegion(Instruction *Inst, LiveBits LB)
     addToWorkList(InInst);
 }
 
+static Constant *undefDeadConstElements(Constant *C, LiveBits LB) {
+  if (isa<UndefValue>(C) || isa<ConstantAggregateZero>(C))
+    return C;
+  if (!C->getType()->isVectorTy()) {
+    IGC_ASSERT(LB.getNumElements() == 1);
+    return LB.get(0) ? C : UndefValue::get(C->getType());
+  }
+  SmallVector<Constant *, 8> NewElems;
+  for (unsigned i = 0; i < LB.getNumElements(); ++i)
+    NewElems.push_back(LB.get(i)
+                           ? C->getAggregateElement(i)
+                           : UndefValue::get(C->getType()->getScalarType()));
+  return ConstantVector::get(NewElems);
+}
+
 /***********************************************************************
  * processWrRegion : process a wrregion instruction for element liveness
  */
@@ -533,23 +548,9 @@ void GenXDeadVectorRemoval::processWrRegion(Instruction *Inst, LiveBits LB)
       addToWorkList(OldInInst);
     // If some constant values are not in use, set it to undef so ConstantLoader
     // can benefit from it.
-    else if (auto OldInConst = dyn_cast<Constant>(OldInVal)) {
-      Constant *NewInConst = nullptr;
-      if (isa<UndefValue>(OldInConst))
-        NewInConst = UndefValue::get(OldInConst->getType());
-      else if(isa<ConstantAggregateZero>(OldInConst))
-        NewInConst = ConstantAggregateZero::get(OldInConst->getType());
-      else {
-        SmallVector<Constant *, 8> NewElems;
-        for (unsigned i = 0; i < OldInLB.getNumElements(); ++i)
-          NewElems.push_back(OldInLB.get(i) ?
-              OldInConst->getAggregateElement(i) :
-              UndefValue::get(OldInConst->getType()->getScalarType()));
-        NewInConst = ConstantVector::get(NewElems);
-      }
-      IGC_ASSERT(NewInConst);
-      Inst->setOperand(GenXIntrinsic::GenXRegion::OldValueOperandNum, NewInConst);
-    }
+    else if (auto OldInConst = dyn_cast<Constant>(OldInVal))
+      Inst->setOperand(GenXIntrinsic::GenXRegion::OldValueOperandNum,
+                       undefDeadConstElements(OldInConst, OldInLB));
   }
   if (UsedOldInput) {
     // We know that at least one element of the "old value" input is used,
@@ -563,10 +564,20 @@ void GenXDeadVectorRemoval::processWrRegion(Instruction *Inst, LiveBits LB)
  */
 void GenXDeadVectorRemoval::processBitCast(Instruction *Inst, LiveBits LB)
 {
-  auto InInst = dyn_cast<Instruction>(Inst->getOperand(0));
-  if (!InInst)
+  LiveBits InLB;
+  LiveBitsStorage ConstVecLBS;
+  auto InVal = Inst->getOperand(0);
+  if (auto InInst = dyn_cast<Instruction>(InVal))
+    InLB = createLiveBits(InInst);
+  else if (isa<Constant>(InVal)) {
+    unsigned NumElems =
+        isa<VectorType>(InVal->getType())
+            ? cast<VectorType>(InVal->getType())->getNumElements()
+            : 1;
+    ConstVecLBS.setNumElements(NumElems);
+    InLB = LiveBits(&ConstVecLBS, NumElems);
+  } else
     return;
-  LiveBits InLB = createLiveBits(InInst);
   bool Modified = false;
   if (InLB.getNumElements() == LB.getNumElements())
     Modified = InLB.orBits(LB);
@@ -589,8 +600,12 @@ void GenXDeadVectorRemoval::processBitCast(Instruction *Inst, LiveBits LB)
         Modified |= InLB.set(Idx);
     }
   }
-  if (Modified)
-    addToWorkList(InInst);
+  if (Modified) {
+    if (auto InInst = dyn_cast<Instruction>(InVal))
+      addToWorkList(InInst);
+    else if (auto InConst = dyn_cast<Constant>(InVal))
+      Inst->setOperand(0, undefDeadConstElements(InConst, InLB));
+  }
 }
 
 /***********************************************************************