1 files changed, 35 insertions, 0 deletions
diff --git a/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp b/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
index 78bc5f49d0a..53374b0cde1 100644
--- a/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
@@ -1878,6 +1878,8 @@ LegalizerHelper::lower(MachineInstr &MI, unsigned TypeIdx, LLT Ty) {
   case G_FMINNUM:
   case G_FMAXNUM:
     return lowerFMinNumMaxNum(MI);
+  case G_UNMERGE_VALUES:
+    return lowerUnmergeValues(MI);
   }
 }
 
@@ -3500,3 +3502,36 @@ LegalizerHelper::lowerFMinNumMaxNum(MachineInstr &MI) {
   MI.eraseFromParent();
   return Legalized;
 }
+
+LegalizerHelper::LegalizeResult
+LegalizerHelper::lowerUnmergeValues(MachineInstr &MI) {
+  const unsigned NumDst = MI.getNumOperands() - 1;
+  const Register SrcReg = MI.getOperand(NumDst).getReg();
+  LLT SrcTy = MRI.getType(SrcReg);
+
+  Register Dst0Reg = MI.getOperand(0).getReg();
+  LLT DstTy = MRI.getType(Dst0Reg);
+
+
+  // Expand scalarizing unmerge as bitcast to integer and shift.
+  if (!DstTy.isVector() && SrcTy.isVector() &&
+      SrcTy.getElementType() == DstTy) {
+    LLT IntTy = LLT::scalar(SrcTy.getSizeInBits());
+    Register Cast = MIRBuilder.buildBitcast(IntTy, SrcReg).getReg(0);
+
+    MIRBuilder.buildTrunc(Dst0Reg, Cast);
+
+    const unsigned DstSize = DstTy.getSizeInBits();
+    unsigned Offset = DstSize;
+    for (unsigned I = 1; I != NumDst; ++I, Offset += DstSize) {
+      auto ShiftAmt = MIRBuilder.buildConstant(IntTy, Offset);
+      auto Shift = MIRBuilder.buildLShr(IntTy, Cast, ShiftAmt);
+      MIRBuilder.buildTrunc(MI.getOperand(I), Shift);
+    }
+
+    MI.eraseFromParent();
+    return Legalized;
+  }
+
+  return UnableToLegalize;
+}