fixup! Use INSERT_SUBVECTOR intead of using many CONCAT_VECTORS

Author: mshockwave

llvm/lib/Target/RISCV/RISCVISelLowering.cpp

@@ -5555,15 +5555,12 @@ static SDValue lowerVECTOR_SHUFFLE(SDValue Op, SelectionDAG &DAG,
           SDValue Hi =
               getDeinterleaveShiftAndTrunc(DL, SubVT, V2, Factor, Index, DAG);
 
-          MVT NewVT = SubVT.getDoubleNumVectorElementsVT();
-          SDValue Concat = DAG.getNode(ISD::CONCAT_VECTORS, DL, NewVT, Lo, Hi);
-          for (unsigned F = Factor; F > 2; F >>= 1) {
-            SDValue Undef = DAG.getUNDEF(NewVT);
-            NewVT = NewVT.getDoubleNumVectorElementsVT();
-            Concat = DAG.getNode(ISD::CONCAT_VECTORS, DL, NewVT, Concat, Undef);
-          }
-
-          return Concat;
+          SDValue Vec = DAG.getUNDEF(VT);
+          Vec = DAG.getNode(ISD::INSERT_SUBVECTOR, DL, VT, Vec, Lo,
+                            DAG.getVectorIdxConstant(0, DL));
+          return DAG.getNode(
+              ISD::INSERT_SUBVECTOR, DL, VT, Vec, Hi,
+              DAG.getVectorIdxConstant(SubVT.getVectorMinNumElements(), DL));
         }
       }
     }

llvm/test/CodeGen/RISCV/rvv/fixed-vectors-shuffle-deinterleave.ll

@@ -378,7 +378,7 @@ define void @deinterleave4_0_i8_two_source(ptr %in0, ptr %in1, ptr %out) {
 ; CHECK-NEXT:    vsetvli zero, zero, e8, mf8, ta, ma
 ; CHECK-NEXT:    vnsrl.wi v8, v8, 0
 ; CHECK-NEXT:    vnsrl.wi v9, v9, 0
-; CHECK-NEXT:    vsetivli zero, 4, e8, mf4, ta, ma
+; CHECK-NEXT:    vsetivli zero, 4, e8, mf2, tu, ma
 ; CHECK-NEXT:    vslideup.vi v9, v8, 2
 ; CHECK-NEXT:    vsetivli zero, 8, e8, mf2, ta, ma
 ; CHECK-NEXT:    vse8.v v9, (a2)
@@ -403,7 +403,7 @@ define void @deinterleave4_8_i8_two_source(ptr %in0, ptr %in1, ptr %out) {
 ; CHECK-NEXT:    vsetvli zero, zero, e8, mf8, ta, ma
 ; CHECK-NEXT:    vnsrl.wi v8, v8, 0
 ; CHECK-NEXT:    vnsrl.wi v9, v9, 0
-; CHECK-NEXT:    vsetivli zero, 4, e8, mf4, ta, ma
+; CHECK-NEXT:    vsetivli zero, 4, e8, mf2, tu, ma
 ; CHECK-NEXT:    vslideup.vi v9, v8, 2
 ; CHECK-NEXT:    vsetivli zero, 8, e8, mf2, ta, ma
 ; CHECK-NEXT:    vse8.v v9, (a2)