[AIE2P] Fix legalization of unmerge of v8s8

The generic legalization creates extracts which are custom legalized
using unmerges resulting in an infinite loop. This fixes this by
implementing custom legalization for unmerge.

Author: khallouh

llvm/lib/Target/AIE/AIELegalizerHelper.cpp

@@ -125,19 +125,20 @@ bool AIELegalizerHelper::pack32BitVector(LegalizerHelper &Helper,
   return true;
 }
 
-bool AIELegalizerHelper::unpack32BitVector(LegalizerHelper &Helper,
-                                           MachineInstr &MI,
-                                           Register SourceReg) const {
+// Unpack 32 bit or 64 bit vectors
+bool AIELegalizerHelper::unpackVector(LegalizerHelper &Helper, MachineInstr &MI,
+                                      Register SourceReg) const {
   MachineIRBuilder &MIRBuilder = Helper.MIRBuilder;
   MachineRegisterInfo &MRI = *MIRBuilder.getMRI();
 
   const LLT SourceRegTy = MRI.getType(SourceReg);
-  assert(SourceRegTy.getSizeInBits() == 32 &&
-         "cannot unpack vectors larger or smaller than 32-bit");
+  unsigned SourceRegSize = SourceRegTy.getSizeInBits();
+  assert((SourceRegSize == 32 || SourceRegSize == 64) &&
+         "cannot unpack vectors other than 32-bit or 64-bit");
 
-  const LLT S32 = LLT::scalar(32);
+  const LLT Type = LLT::scalar(SourceRegSize);
   unsigned Offset = 0;
-  Register DstCastReg = MRI.createGenericVirtualRegister(S32);
+  Register DstCastReg = MRI.createGenericVirtualRegister(Type);
 
   MachineOperand *Operand = MI.operands_begin(),
                  *OperandEnd = MI.operands_end() - 1;
@@ -149,9 +150,9 @@ bool AIELegalizerHelper::unpack32BitVector(LegalizerHelper &Helper,
     // optimized out in O0.
     if (Offset != 0) {
       const MachineInstrBuilder ShiftConstant =
-          MIRBuilder.buildConstant(S32, Offset);
+          MIRBuilder.buildConstant(Type, Offset);
       const MachineInstrBuilder Masked =
-          MIRBuilder.buildLShr(S32, DstCastReg, ShiftConstant);
+          MIRBuilder.buildLShr(Type, DstCastReg, ShiftConstant);
       MIRBuilder.buildTrunc(DestinationOperand, Masked);
 
     } else {
@@ -345,8 +346,9 @@ bool AIELegalizerHelper::legalizeG_UNMERGE_VALUES(LegalizerHelper &Helper,
              LastTy.getSizeInBits() &&
          "This operation is only supported for vectors");
 
-  if (LastTy.getSizeInBits() == 32)
-    return unpack32BitVector(Helper, MI, LastReg);
+  unsigned LastTySize = LastTy.getSizeInBits();
+  if (LastTySize == 32 || LastTySize == 64)
+    return unpackVector(Helper, MI, LastReg);
 
   // Pad vectors of 128-bit vectors to 256-bit
   Register TargetReg = LastReg;

llvm/lib/Target/AIE/AIELegalizerHelper.h

@@ -83,8 +83,8 @@ class AIELegalizerHelper {
   // Helper functions for legalization
   bool pack32BitVector(LegalizerHelper &Helper, MachineInstr &MI,
                        Register SourceReg) const;
-  bool unpack32BitVector(LegalizerHelper &Helper, MachineInstr &MI,
-                         Register SourceReg) const;
+  bool unpackVector(LegalizerHelper &Helper, MachineInstr &MI,
+                    Register SourceReg) const;
   bool legalizeG_UNMERGE_VALUES_128bit(LegalizerHelper &Helper,
                                        MachineInstr &MI) const;
   bool legalizeG_AIE_EXTRACT_VECTOR_ELT(LegalizerHelper &Helper,