GlobalISel: Partially implement widenScalar for MERGE_VALUES
llvm-svn: 352560
diff --git a/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp b/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
index 7e3c0ed..180d3d5 100644
--- a/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
@@ -784,6 +784,46 @@
switch (MI.getOpcode()) {
default:
return UnableToLegalize;
+ case TargetOpcode::G_MERGE_VALUES: {
+ if (TypeIdx != 1)
+ return UnableToLegalize;
+
+ unsigned DstReg = MI.getOperand(0).getReg();
+ LLT DstTy = MRI.getType(DstReg);
+ if (!DstTy.isScalar())
+ return UnableToLegalize;
+
+ unsigned NumSrc = MI.getNumOperands() - 1;
+ unsigned EltSize = DstTy.getSizeInBits() / NumSrc;
+ LLT EltTy = LLT::scalar(EltSize);
+
+ unsigned ResultReg = MRI.createGenericVirtualRegister(DstTy);
+ unsigned Offset = 0;
+ for (unsigned I = 1, E = MI.getNumOperands(); I != E; ++I,
+ Offset += EltSize) {
+ assert(MRI.getType(MI.getOperand(I).getReg()) == EltTy);
+
+ unsigned ShiftAmt = MRI.createGenericVirtualRegister(DstTy);
+ unsigned Shl = MRI.createGenericVirtualRegister(DstTy);
+ unsigned ZextInput = MRI.createGenericVirtualRegister(DstTy);
+ MIRBuilder.buildZExt(ZextInput, MI.getOperand(I).getReg());
+
+ if (Offset != 0) {
+ unsigned NextResult = I + 1 == E ? DstReg :
+ MRI.createGenericVirtualRegister(DstTy);
+
+ MIRBuilder.buildConstant(ShiftAmt, Offset);
+ MIRBuilder.buildShl(Shl, ZextInput, ShiftAmt);
+ MIRBuilder.buildOr(NextResult, ResultReg, Shl);
+ ResultReg = NextResult;
+ } else {
+ ResultReg = ZextInput;
+ }
+ }
+
+ MI.eraseFromParent();
+ return Legalized;
+ }
case TargetOpcode::G_UADDO:
case TargetOpcode::G_USUBO: {
if (TypeIdx == 1)