diff --git a/llvm/lib/Target/RISCV/RISCVInstrInfoZb.td b/llvm/lib/Target/RISCV/RISCVInstrInfoZb.td
--- a/llvm/lib/Target/RISCV/RISCVInstrInfoZb.td
+++ b/llvm/lib/Target/RISCV/RISCVInstrInfoZb.td
@@ -1174,6 +1174,14 @@
           (SH2ADD_UW GPR:$rs1, GPR:$rs2)>;
 def : Pat<(i64 (add (and (shl GPR:$rs1, (i64 3)), 0x7FFFFFFFF), non_imm12:$rs2)),
           (SH3ADD_UW GPR:$rs1, GPR:$rs2)>;
+
+// Use SRLI to clear the LSBs and SHXADD_UW to mask and shift.
+def : Pat<(i64 (add (and GPR:$rs1, 0x1FFFFFFFE), non_imm12:$rs2)),
+          (SH1ADD_UW (SRLI GPR:$rs1, 1), GPR:$rs2)>;
+def : Pat<(i64 (add (and GPR:$rs1, 0x3FFFFFFFC), non_imm12:$rs2)),
+          (SH2ADD_UW (SRLI GPR:$rs1, 2), GPR:$rs2)>;
+def : Pat<(i64 (add (and GPR:$rs1, 0x7FFFFFFF8), non_imm12:$rs2)),
+          (SH3ADD_UW (SRLI GPR:$rs1, 3), GPR:$rs2)>;
 } // Predicates = [HasStdExtZba, IsRV64]
 
 let Predicates = [HasStdExtZbcOrZbkc] in {
diff --git a/llvm/test/CodeGen/RISCV/rv64zba.ll b/llvm/test/CodeGen/RISCV/rv64zba.ll
--- a/llvm/test/CodeGen/RISCV/rv64zba.ll
+++ b/llvm/test/CodeGen/RISCV/rv64zba.ll
@@ -1167,15 +1167,22 @@
 ; This the IR you get from InstCombine if take the difference of 2 pointers and
 ; cast is to unsigned before using as an index.
 define signext i16 @sh1adduw_ptrdiff(i64 %diff, i16* %baseptr) {
-; CHECK-LABEL: sh1adduw_ptrdiff:
-; CHECK:       # %bb.0:
-; CHECK-NEXT:    li a2, 1
-; CHECK-NEXT:    slli a2, a2, 33
-; CHECK-NEXT:    addi a2, a2, -2
-; CHECK-NEXT:    and a0, a0, a2
-; CHECK-NEXT:    add a0, a1, a0
-; CHECK-NEXT:    lh a0, 0(a0)
-; CHECK-NEXT:    ret
+; RV64I-LABEL: sh1adduw_ptrdiff:
+; RV64I:       # %bb.0:
+; RV64I-NEXT:    li a2, 1
+; RV64I-NEXT:    slli a2, a2, 33
+; RV64I-NEXT:    addi a2, a2, -2
+; RV64I-NEXT:    and a0, a0, a2
+; RV64I-NEXT:    add a0, a1, a0
+; RV64I-NEXT:    lh a0, 0(a0)
+; RV64I-NEXT:    ret
+;
+; RV64ZBA-LABEL: sh1adduw_ptrdiff:
+; RV64ZBA:       # %bb.0:
+; RV64ZBA-NEXT:    srli a0, a0, 1
+; RV64ZBA-NEXT:    sh1add.uw a0, a0, a1
+; RV64ZBA-NEXT:    lh a0, 0(a0)
+; RV64ZBA-NEXT:    ret
   %ptrdiff = lshr exact i64 %diff, 1
   %cast = and i64 %ptrdiff, 4294967295
   %ptr = getelementptr inbounds i16, i16* %baseptr, i64 %cast
@@ -1184,15 +1191,22 @@
 }
 
 define signext i32 @sh2adduw_ptrdiff(i64 %diff, i32* %baseptr) {
-; CHECK-LABEL: sh2adduw_ptrdiff:
-; CHECK:       # %bb.0:
-; CHECK-NEXT:    li a2, 1
-; CHECK-NEXT:    slli a2, a2, 34
-; CHECK-NEXT:    addi a2, a2, -4
-; CHECK-NEXT:    and a0, a0, a2
-; CHECK-NEXT:    add a0, a1, a0
-; CHECK-NEXT:    lw a0, 0(a0)
-; CHECK-NEXT:    ret
+; RV64I-LABEL: sh2adduw_ptrdiff:
+; RV64I:       # %bb.0:
+; RV64I-NEXT:    li a2, 1
+; RV64I-NEXT:    slli a2, a2, 34
+; RV64I-NEXT:    addi a2, a2, -4
+; RV64I-NEXT:    and a0, a0, a2
+; RV64I-NEXT:    add a0, a1, a0
+; RV64I-NEXT:    lw a0, 0(a0)
+; RV64I-NEXT:    ret
+;
+; RV64ZBA-LABEL: sh2adduw_ptrdiff:
+; RV64ZBA:       # %bb.0:
+; RV64ZBA-NEXT:    srli a0, a0, 2
+; RV64ZBA-NEXT:    sh2add.uw a0, a0, a1
+; RV64ZBA-NEXT:    lw a0, 0(a0)
+; RV64ZBA-NEXT:    ret
   %ptrdiff = lshr exact i64 %diff, 2
   %cast = and i64 %ptrdiff, 4294967295
   %ptr = getelementptr inbounds i32, i32* %baseptr, i64 %cast
@@ -1201,15 +1215,22 @@
 }
 
 define i64 @sh3adduw_ptrdiff(i64 %diff, i64* %baseptr) {
-; CHECK-LABEL: sh3adduw_ptrdiff:
-; CHECK:       # %bb.0:
-; CHECK-NEXT:    li a2, 1
-; CHECK-NEXT:    slli a2, a2, 35
-; CHECK-NEXT:    addi a2, a2, -8
-; CHECK-NEXT:    and a0, a0, a2
-; CHECK-NEXT:    add a0, a1, a0
-; CHECK-NEXT:    ld a0, 0(a0)
-; CHECK-NEXT:    ret
+; RV64I-LABEL: sh3adduw_ptrdiff:
+; RV64I:       # %bb.0:
+; RV64I-NEXT:    li a2, 1
+; RV64I-NEXT:    slli a2, a2, 35
+; RV64I-NEXT:    addi a2, a2, -8
+; RV64I-NEXT:    and a0, a0, a2
+; RV64I-NEXT:    add a0, a1, a0
+; RV64I-NEXT:    ld a0, 0(a0)
+; RV64I-NEXT:    ret
+;
+; RV64ZBA-LABEL: sh3adduw_ptrdiff:
+; RV64ZBA:       # %bb.0:
+; RV64ZBA-NEXT:    srli a0, a0, 3
+; RV64ZBA-NEXT:    sh3add.uw a0, a0, a1
+; RV64ZBA-NEXT:    ld a0, 0(a0)
+; RV64ZBA-NEXT:    ret
   %ptrdiff = lshr exact i64 %diff, 3
   %cast = and i64 %ptrdiff, 4294967295
   %ptr = getelementptr inbounds i64, i64* %baseptr, i64 %cast