fixup! move to widenScalar

Author: michaelmaitland

llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp

@@ -3276,6 +3276,33 @@ LegalizerHelper::widenScalar(MachineInstr &MI, unsigned TypeIdx, LLT WideTy) {
     Observer.changedInstr(MI);
     return Legalized;
   }
+  case TargetOpcode::G_INSERT_SUBVECTOR: {
+    if (TypeIdx != 0)
+      return UnableToLegalize;
+
+    GInsertSubvector &IS = cast<GInsertSubvector>(MI);
+    Register BigVec = IS.getBigVec();
+    Register SubVec = IS.getSubVec();
+
+    LLT SubVecTy = MRI.getType(SubVec);
+    LLT SubVecWideTy = SubVecTy.changeElementType(WideTy.getElementType());
+
+    // Widen the G_INSERT_SUBVECTOR
+    auto BigZExt = MIRBuilder.buildZExt(WideTy, BigVec);
+    auto SubZExt = MIRBuilder.buildZExt(SubVecWideTy, SubVec);
+    auto WideInsert = MIRBuilder.buildInsertSubvector(WideTy, BigZExt, SubZExt,
+                                                      IS.getIndexImm());
+
+    // Truncate back down
+    auto SplatZero = MIRBuilder.buildSplatVector(
+        WideTy, MIRBuilder.buildConstant(WideTy.getElementType(), 0));
+    MIRBuilder.buildICmp(CmpInst::Predicate::ICMP_NE, IS.getReg(0), WideInsert,
+                         SplatZero);
+
+    MI.eraseFromParent();
+
+    return Legalized;
+  }
   }
 }
 

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

@@ -1064,16 +1064,8 @@ bool RISCVLegalizerInfo::legalizeInsertSubvector(MachineInstr &MI,
     // This poses a problem when we wish to insert a scalable vector which
     // can't be re-expressed as a larger type. Just choose the slow path and
     // extend to a larger type, then truncate back down.
-    BigTy = BigTy.changeElementType(LLT::scalar(8));
-    LitTy = LitTy.changeElementType(LLT::scalar(8));
-    auto BigZExt = MIB.buildZExt(BigTy, BigVec);
-    auto LitZExt = MIB.buildZExt(LitTy, LitVec);
-    auto Insert = MIB.buildInsertSubvector(BigTy, BigZExt, LitZExt, Idx);
-    auto SplatZero = MIB.buildSplatVector(
-        BigTy, MIB.buildConstant(BigTy.getElementType(), 0));
-    MIB.buildICmp(CmpInst::Predicate::ICMP_NE, Dst, Insert, SplatZero);
-    MI.eraseFromParent();
-    return true;
+    LLT ExtBigTy = BigTy.changeElementType(LLT::scalar(8));
+    return Helper.widenScalar(IS, 0, ExtBigTy);
   }
 
   const RISCVRegisterInfo *TRI = STI.getRegisterInfo();