Index: llvm/lib/Target/RISCV/RISCVISelDAGToDAG.cpp
===================================================================
--- llvm/lib/Target/RISCV/RISCVISelDAGToDAG.cpp
+++ llvm/lib/Target/RISCV/RISCVISelDAGToDAG.cpp
@@ -528,6 +528,60 @@
 
     break;
   }
+
+  // Optimize (add (shl x, c0), (shl y, c1)) ->
+  //          (SLLI (SH*ADD y, x), c0), if c1-c0 equals to [1|2|3].
+  case ISD::ADD: {
+    // Perform this optimization only in the zba extension.
+    if (!Subtarget->hasStdExtZba())
+      break;
+
+    // Skip for vector types.
+    if (VT.isVector())
+      break;
+
+    // The two operand nodes must be SHL and have no other use.
+    SDValue N0 = Node->getOperand(0);
+    SDValue N1 = Node->getOperand(1);
+    if (N0.getOpcode() != ISD::SHL || N1.getOpcode() != ISD::SHL ||
+        !N0.hasOneUse() || !N1.hasOneUse())
+      break;
+
+    // Check c0 and c1.
+    auto *NC0 = dyn_cast<ConstantSDNode>(N0->getOperand(1));
+    auto *NC1 = dyn_cast<ConstantSDNode>(N1->getOperand(1));
+    if (!NC0 || !NC1)
+      break;
+    int64_t C0 = NC0->getSExtValue();
+    int64_t C1 = NC1->getSExtValue();
+    if (C0 <= 0 || C1 <= 0 || C0 >= Subtarget->getXLen() ||
+        C1 >= Subtarget->getXLen())
+      break;
+    int64_t Bits = std::min(C0, C1);
+    int64_t Diff = std::max(C0, C1) - Bits;
+
+    // Select SH1ADD/SH2ADD/SH3ADD or skip.
+    unsigned Opc;
+    if (Diff == 1)
+      Opc = RISCV::SH1ADD;
+    else if (Diff == 2)
+      Opc = RISCV::SH2ADD;
+    else if (Diff == 3)
+      Opc = RISCV::SH3ADD;
+    else
+      break;
+
+    // Build machine nodes and replace SDNodes.
+    SDValue NS = (C0 < C1) ? N0->getOperand(0) : N1->getOperand(0);
+    SDValue NL = (C0 > C1) ? N0->getOperand(0) : N1->getOperand(0);
+    SDNode *NAD = CurDAG->getMachineNode(Opc, DL, VT, NL, NS);
+    SDNode *NSH =
+        CurDAG->getMachineNode(RISCV::SLLI, DL, VT, SDValue(NAD, 0),
+                               CurDAG->getTargetConstant(Bits, DL, VT));
+    ReplaceNode(Node, NSH);
+    return;
+  }
+
   case ISD::AND: {
     auto *N1C = dyn_cast<ConstantSDNode>(Node->getOperand(1));
     if (!N1C)
Index: llvm/test/CodeGen/RISCV/rv32zba.ll
===================================================================
--- llvm/test/CodeGen/RISCV/rv32zba.ll
+++ llvm/test/CodeGen/RISCV/rv32zba.ll
@@ -796,16 +796,14 @@
 ;
 ; RV32B-LABEL: addshl_5_6:
 ; RV32B:       # %bb.0:
+; RV32B-NEXT:    sh1add a0, a1, a0
 ; RV32B-NEXT:    slli a0, a0, 5
-; RV32B-NEXT:    slli a1, a1, 6
-; RV32B-NEXT:    add a0, a0, a1
 ; RV32B-NEXT:    ret
 ;
 ; RV32ZBA-LABEL: addshl_5_6:
 ; RV32ZBA:       # %bb.0:
+; RV32ZBA-NEXT:    sh1add a0, a1, a0
 ; RV32ZBA-NEXT:    slli a0, a0, 5
-; RV32ZBA-NEXT:    slli a1, a1, 6
-; RV32ZBA-NEXT:    add a0, a0, a1
 ; RV32ZBA-NEXT:    ret
   %c = shl i32 %a, 5
   %d = shl i32 %b, 6
@@ -823,16 +821,14 @@
 ;
 ; RV32B-LABEL: addshl_5_7:
 ; RV32B:       # %bb.0:
+; RV32B-NEXT:    sh2add a0, a1, a0
 ; RV32B-NEXT:    slli a0, a0, 5
-; RV32B-NEXT:    slli a1, a1, 7
-; RV32B-NEXT:    add a0, a0, a1
 ; RV32B-NEXT:    ret
 ;
 ; RV32ZBA-LABEL: addshl_5_7:
 ; RV32ZBA:       # %bb.0:
+; RV32ZBA-NEXT:    sh2add a0, a1, a0
 ; RV32ZBA-NEXT:    slli a0, a0, 5
-; RV32ZBA-NEXT:    slli a1, a1, 7
-; RV32ZBA-NEXT:    add a0, a0, a1
 ; RV32ZBA-NEXT:    ret
   %c = shl i32 %a, 5
   %d = shl i32 %b, 7
@@ -850,16 +846,14 @@
 ;
 ; RV32B-LABEL: addshl_5_8:
 ; RV32B:       # %bb.0:
+; RV32B-NEXT:    sh3add a0, a1, a0
 ; RV32B-NEXT:    slli a0, a0, 5
-; RV32B-NEXT:    slli a1, a1, 8
-; RV32B-NEXT:    add a0, a0, a1
 ; RV32B-NEXT:    ret
 ;
 ; RV32ZBA-LABEL: addshl_5_8:
 ; RV32ZBA:       # %bb.0:
+; RV32ZBA-NEXT:    sh3add a0, a1, a0
 ; RV32ZBA-NEXT:    slli a0, a0, 5
-; RV32ZBA-NEXT:    slli a1, a1, 8
-; RV32ZBA-NEXT:    add a0, a0, a1
 ; RV32ZBA-NEXT:    ret
   %c = shl i32 %a, 5
   %d = shl i32 %b, 8
Index: llvm/test/CodeGen/RISCV/rv64zba.ll
===================================================================
--- llvm/test/CodeGen/RISCV/rv64zba.ll
+++ llvm/test/CodeGen/RISCV/rv64zba.ll
@@ -1407,16 +1407,14 @@
 ;
 ; RV64B-LABEL: addshl32_5_6:
 ; RV64B:       # %bb.0:
+; RV64B-NEXT:    sh1add a0, a1, a0
 ; RV64B-NEXT:    slliw a0, a0, 5
-; RV64B-NEXT:    slliw a1, a1, 6
-; RV64B-NEXT:    addw a0, a0, a1
 ; RV64B-NEXT:    ret
 ;
 ; RV64ZBA-LABEL: addshl32_5_6:
 ; RV64ZBA:       # %bb.0:
+; RV64ZBA-NEXT:    sh1add a0, a1, a0
 ; RV64ZBA-NEXT:    slliw a0, a0, 5
-; RV64ZBA-NEXT:    slliw a1, a1, 6
-; RV64ZBA-NEXT:    addw a0, a0, a1
 ; RV64ZBA-NEXT:    ret
   %c = shl i32 %a, 5
   %d = shl i32 %b, 6
@@ -1434,16 +1432,14 @@
 ;
 ; RV64B-LABEL: addshl64_5_6:
 ; RV64B:       # %bb.0:
+; RV64B-NEXT:    sh1add a0, a1, a0
 ; RV64B-NEXT:    slli a0, a0, 5
-; RV64B-NEXT:    slli a1, a1, 6
-; RV64B-NEXT:    add a0, a0, a1
 ; RV64B-NEXT:    ret
 ;
 ; RV64ZBA-LABEL: addshl64_5_6:
 ; RV64ZBA:       # %bb.0:
+; RV64ZBA-NEXT:    sh1add a0, a1, a0
 ; RV64ZBA-NEXT:    slli a0, a0, 5
-; RV64ZBA-NEXT:    slli a1, a1, 6
-; RV64ZBA-NEXT:    add a0, a0, a1
 ; RV64ZBA-NEXT:    ret
   %c = shl i64 %a, 5
   %d = shl i64 %b, 6
@@ -1461,16 +1457,14 @@
 ;
 ; RV64B-LABEL: addshl32_5_7:
 ; RV64B:       # %bb.0:
+; RV64B-NEXT:    sh2add a0, a1, a0
 ; RV64B-NEXT:    slliw a0, a0, 5
-; RV64B-NEXT:    slliw a1, a1, 7
-; RV64B-NEXT:    addw a0, a0, a1
 ; RV64B-NEXT:    ret
 ;
 ; RV64ZBA-LABEL: addshl32_5_7:
 ; RV64ZBA:       # %bb.0:
+; RV64ZBA-NEXT:    sh2add a0, a1, a0
 ; RV64ZBA-NEXT:    slliw a0, a0, 5
-; RV64ZBA-NEXT:    slliw a1, a1, 7
-; RV64ZBA-NEXT:    addw a0, a0, a1
 ; RV64ZBA-NEXT:    ret
   %c = shl i32 %a, 5
   %d = shl i32 %b, 7
@@ -1488,16 +1482,14 @@
 ;
 ; RV64B-LABEL: addshl64_5_7:
 ; RV64B:       # %bb.0:
+; RV64B-NEXT:    sh2add a0, a1, a0
 ; RV64B-NEXT:    slli a0, a0, 5
-; RV64B-NEXT:    slli a1, a1, 7
-; RV64B-NEXT:    add a0, a0, a1
 ; RV64B-NEXT:    ret
 ;
 ; RV64ZBA-LABEL: addshl64_5_7:
 ; RV64ZBA:       # %bb.0:
+; RV64ZBA-NEXT:    sh2add a0, a1, a0
 ; RV64ZBA-NEXT:    slli a0, a0, 5
-; RV64ZBA-NEXT:    slli a1, a1, 7
-; RV64ZBA-NEXT:    add a0, a0, a1
 ; RV64ZBA-NEXT:    ret
   %c = shl i64 %a, 5
   %d = shl i64 %b, 7
@@ -1515,16 +1507,14 @@
 ;
 ; RV64B-LABEL: addshl32_5_8:
 ; RV64B:       # %bb.0:
+; RV64B-NEXT:    sh3add a0, a1, a0
 ; RV64B-NEXT:    slliw a0, a0, 5
-; RV64B-NEXT:    slliw a1, a1, 8
-; RV64B-NEXT:    addw a0, a0, a1
 ; RV64B-NEXT:    ret
 ;
 ; RV64ZBA-LABEL: addshl32_5_8:
 ; RV64ZBA:       # %bb.0:
+; RV64ZBA-NEXT:    sh3add a0, a1, a0
 ; RV64ZBA-NEXT:    slliw a0, a0, 5
-; RV64ZBA-NEXT:    slliw a1, a1, 8
-; RV64ZBA-NEXT:    addw a0, a0, a1
 ; RV64ZBA-NEXT:    ret
   %c = shl i32 %a, 5
   %d = shl i32 %b, 8
@@ -1542,16 +1532,14 @@
 ;
 ; RV64B-LABEL: addshl64_5_8:
 ; RV64B:       # %bb.0:
+; RV64B-NEXT:    sh3add a0, a1, a0
 ; RV64B-NEXT:    slli a0, a0, 5
-; RV64B-NEXT:    slli a1, a1, 8
-; RV64B-NEXT:    add a0, a0, a1
 ; RV64B-NEXT:    ret
 ;
 ; RV64ZBA-LABEL: addshl64_5_8:
 ; RV64ZBA:       # %bb.0:
+; RV64ZBA-NEXT:    sh3add a0, a1, a0
 ; RV64ZBA-NEXT:    slli a0, a0, 5
-; RV64ZBA-NEXT:    slli a1, a1, 8
-; RV64ZBA-NEXT:    add a0, a0, a1
 ; RV64ZBA-NEXT:    ret
   %c = shl i64 %a, 5
   %d = shl i64 %b, 8