[RISCV][GISEL] Legalize and regbankselect vector typed G_IMPLICIT_DEF

Author: michaelmaitland

llvm/lib/Target/RISCV/GISel/RISCVLegalizerInfo.cpp

@@ -217,8 +217,11 @@ RISCVLegalizerInfo::RISCVLegalizerInfo(const RISCVSubtarget &ST)
     ConstantActions.customFor({s64});
   ConstantActions.widenScalarToNextPow2(0).clampScalar(0, s32, sXLen);
 
+  // TODO: transform illegal vector types into legal vector type
   getActionDefinitionsBuilder(G_IMPLICIT_DEF)
       .legalFor({s32, sXLen, p0})
+      .legalIf(typeIsLegalBoolVec(0, BoolVecTys, ST))
+      .legalIf(typeIsLegalIntOrFPVec(0, IntOrFPVecTys, ST))
       .widenScalarToNextPow2(0)
       .clampScalar(0, s32, sXLen);
 

llvm/lib/Target/RISCV/GISel/RISCVRegisterBankInfo.cpp

@@ -343,14 +343,20 @@ RISCVRegisterBankInfo::getInstrMapping(const MachineInstr &MI) const {
   }
   case TargetOpcode::G_IMPLICIT_DEF: {
     Register Dst = MI.getOperand(0).getReg();
+    LLT DstTy = MRI.getType(Dst);
+    uint64_t DstMinSize = DstTy.getSizeInBits().getKnownMinValue();
     auto Mapping = GPRValueMapping;
     // FIXME: May need to do a better job determining when to use FPRB.
     // For example, the look through COPY case:
     // %0:_(s32) = G_IMPLICIT_DEF
     // %1:_(s32) = COPY %0
     // $f10_d = COPY %1(s32)
     if (anyUseOnlyUseFP(Dst, MRI, TRI))
-      Mapping = getFPValueMapping(MRI.getType(Dst).getSizeInBits());
+      Mapping = getFPValueMapping(DstMinSize);
+
+    if (DstTy.isVector())
+      Mapping = getVRBValueMapping(DstMinSize);
+
     return getInstructionMapping(DefaultMappingID, /*Cost=*/1, Mapping,
                                  NumOperands);
   }