diff --git a/llvm/test/CodeGen/RISCV/rv32zpn-bitreverse.ll b/llvm/test/CodeGen/RISCV/rv32zpn-bitreverse.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/CodeGen/RISCV/rv32zpn-bitreverse.ll
@@ -0,0 +1,400 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc -mtriple=riscv32 -mattr=+experimental-b -verify-machineinstrs < %s \
+; RUN:   | FileCheck %s --check-prefixes=RV32IB
+; RUN: llc -mtriple=riscv32 -mattr=+experimental-p -verify-machineinstrs < %s \
+; RUN:   | FileCheck %s --check-prefixes=RV32IP
+; RUN: llc -mtriple=riscv32 -mattr=+experimental-zpn -verify-machineinstrs < %s \
+; RUN:   | FileCheck %s --check-prefixes=RV32IPN
+; RUN: llc -mtriple=riscv32 -mattr=+experimental-b,+experimental-p -verify-machineinstrs < %s \
+; RUN:   | FileCheck %s --check-prefixes=RV32IBP
+
+declare i8 @llvm.bitreverse.i8(i8)
+declare i16 @llvm.bitreverse.i16(i16)
+declare i32 @llvm.bitreverse.i32(i32)
+declare i64 @llvm.bitreverse.i64(i64)
+
+define zeroext i8 @bitreverse_i8(i8 zeroext %a) nounwind {
+; RV32IB-LABEL: bitreverse_i8:
+; RV32IB:       # %bb.0:
+; RV32IB-NEXT:    rev.b a0, a0
+; RV32IB-NEXT:    ret
+;
+; RV32IP-LABEL: bitreverse_i8:
+; RV32IP:       # %bb.0:
+; RV32IP-NEXT:    srli a1, a0, 4
+; RV32IP-NEXT:    andi a0, a0, 15
+; RV32IP-NEXT:    slli a0, a0, 4
+; RV32IP-NEXT:    or a0, a1, a0
+; RV32IP-NEXT:    andi a1, a0, 51
+; RV32IP-NEXT:    slli a1, a1, 2
+; RV32IP-NEXT:    andi a0, a0, 204
+; RV32IP-NEXT:    srli a0, a0, 2
+; RV32IP-NEXT:    or a0, a0, a1
+; RV32IP-NEXT:    andi a1, a0, 85
+; RV32IP-NEXT:    slli a1, a1, 1
+; RV32IP-NEXT:    andi a0, a0, 170
+; RV32IP-NEXT:    srli a0, a0, 1
+; RV32IP-NEXT:    or a0, a0, a1
+; RV32IP-NEXT:    ret
+;
+; RV32IPN-LABEL: bitreverse_i8:
+; RV32IPN:       # %bb.0:
+; RV32IPN-NEXT:    srli a1, a0, 4
+; RV32IPN-NEXT:    andi a0, a0, 15
+; RV32IPN-NEXT:    slli a0, a0, 4
+; RV32IPN-NEXT:    or a0, a1, a0
+; RV32IPN-NEXT:    andi a1, a0, 51
+; RV32IPN-NEXT:    slli a1, a1, 2
+; RV32IPN-NEXT:    andi a0, a0, 204
+; RV32IPN-NEXT:    srli a0, a0, 2
+; RV32IPN-NEXT:    or a0, a0, a1
+; RV32IPN-NEXT:    andi a1, a0, 85
+; RV32IPN-NEXT:    slli a1, a1, 1
+; RV32IPN-NEXT:    andi a0, a0, 170
+; RV32IPN-NEXT:    srli a0, a0, 1
+; RV32IPN-NEXT:    or a0, a0, a1
+; RV32IPN-NEXT:    ret
+;
+; RV32IBP-LABEL: bitreverse_i8:
+; RV32IBP:       # %bb.0:
+; RV32IBP-NEXT:    rev.b a0, a0
+; RV32IBP-NEXT:    ret
+  %ret = tail call i8 @llvm.bitreverse.i8(i8 %a)
+  ret i8 %ret
+}
+
+define zeroext i16 @bitreverse_i16(i16 zeroext %a) nounwind {
+; RV32IB-LABEL: bitreverse_i16:
+; RV32IB:       # %bb.0:
+; RV32IB-NEXT:    rev.h a0, a0
+; RV32IB-NEXT:    ret
+;
+; RV32IP-LABEL: bitreverse_i16:
+; RV32IP:       # %bb.0:
+; RV32IP-NEXT:    srli a1, a0, 8
+; RV32IP-NEXT:    slli a0, a0, 8
+; RV32IP-NEXT:    or a0, a0, a1
+; RV32IP-NEXT:    lui a1, 1
+; RV32IP-NEXT:    addi a1, a1, -241
+; RV32IP-NEXT:    and a1, a0, a1
+; RV32IP-NEXT:    slli a1, a1, 4
+; RV32IP-NEXT:    lui a2, 15
+; RV32IP-NEXT:    addi a2, a2, 240
+; RV32IP-NEXT:    and a0, a0, a2
+; RV32IP-NEXT:    srli a0, a0, 4
+; RV32IP-NEXT:    or a0, a0, a1
+; RV32IP-NEXT:    lui a1, 3
+; RV32IP-NEXT:    addi a1, a1, 819
+; RV32IP-NEXT:    and a1, a0, a1
+; RV32IP-NEXT:    slli a1, a1, 2
+; RV32IP-NEXT:    lui a2, 13
+; RV32IP-NEXT:    addi a2, a2, -820
+; RV32IP-NEXT:    and a0, a0, a2
+; RV32IP-NEXT:    srli a0, a0, 2
+; RV32IP-NEXT:    or a0, a0, a1
+; RV32IP-NEXT:    lui a1, 5
+; RV32IP-NEXT:    addi a1, a1, 1365
+; RV32IP-NEXT:    and a1, a0, a1
+; RV32IP-NEXT:    slli a1, a1, 1
+; RV32IP-NEXT:    lui a2, 11
+; RV32IP-NEXT:    addi a2, a2, -1366
+; RV32IP-NEXT:    and a0, a0, a2
+; RV32IP-NEXT:    srli a0, a0, 1
+; RV32IP-NEXT:    or a0, a0, a1
+; RV32IP-NEXT:    ret
+;
+; RV32IPN-LABEL: bitreverse_i16:
+; RV32IPN:       # %bb.0:
+; RV32IPN-NEXT:    srli a1, a0, 8
+; RV32IPN-NEXT:    slli a0, a0, 8
+; RV32IPN-NEXT:    or a0, a0, a1
+; RV32IPN-NEXT:    lui a1, 1
+; RV32IPN-NEXT:    addi a1, a1, -241
+; RV32IPN-NEXT:    and a1, a0, a1
+; RV32IPN-NEXT:    slli a1, a1, 4
+; RV32IPN-NEXT:    lui a2, 15
+; RV32IPN-NEXT:    addi a2, a2, 240
+; RV32IPN-NEXT:    and a0, a0, a2
+; RV32IPN-NEXT:    srli a0, a0, 4
+; RV32IPN-NEXT:    or a0, a0, a1
+; RV32IPN-NEXT:    lui a1, 3
+; RV32IPN-NEXT:    addi a1, a1, 819
+; RV32IPN-NEXT:    and a1, a0, a1
+; RV32IPN-NEXT:    slli a1, a1, 2
+; RV32IPN-NEXT:    lui a2, 13
+; RV32IPN-NEXT:    addi a2, a2, -820
+; RV32IPN-NEXT:    and a0, a0, a2
+; RV32IPN-NEXT:    srli a0, a0, 2
+; RV32IPN-NEXT:    or a0, a0, a1
+; RV32IPN-NEXT:    lui a1, 5
+; RV32IPN-NEXT:    addi a1, a1, 1365
+; RV32IPN-NEXT:    and a1, a0, a1
+; RV32IPN-NEXT:    slli a1, a1, 1
+; RV32IPN-NEXT:    lui a2, 11
+; RV32IPN-NEXT:    addi a2, a2, -1366
+; RV32IPN-NEXT:    and a0, a0, a2
+; RV32IPN-NEXT:    srli a0, a0, 1
+; RV32IPN-NEXT:    or a0, a0, a1
+; RV32IPN-NEXT:    ret
+;
+; RV32IBP-LABEL: bitreverse_i16:
+; RV32IBP:       # %bb.0:
+; RV32IBP-NEXT:    rev.h a0, a0
+; RV32IBP-NEXT:    ret
+  %ret = tail call i16 @llvm.bitreverse.i16(i16 %a)
+  ret i16 %ret
+}
+
+define i32 @bitreverse_i32(i32 %a) nounwind {
+; RV32IB-LABEL: bitreverse_i32:
+; RV32IB:       # %bb.0:
+; RV32IB-NEXT:    rev a0, a0
+; RV32IB-NEXT:    ret
+;
+; RV32IP-LABEL: bitreverse_i32:
+; RV32IP:       # %bb.0:
+; RV32IP-NEXT:    srli a1, a0, 8
+; RV32IP-NEXT:    lui a2, 16
+; RV32IP-NEXT:    addi a2, a2, -256
+; RV32IP-NEXT:    and a1, a1, a2
+; RV32IP-NEXT:    srli a2, a0, 24
+; RV32IP-NEXT:    or a1, a1, a2
+; RV32IP-NEXT:    slli a2, a0, 8
+; RV32IP-NEXT:    lui a3, 4080
+; RV32IP-NEXT:    and a2, a2, a3
+; RV32IP-NEXT:    slli a0, a0, 24
+; RV32IP-NEXT:    or a0, a0, a2
+; RV32IP-NEXT:    or a0, a0, a1
+; RV32IP-NEXT:    lui a1, 61681
+; RV32IP-NEXT:    addi a1, a1, -241
+; RV32IP-NEXT:    and a1, a0, a1
+; RV32IP-NEXT:    slli a1, a1, 4
+; RV32IP-NEXT:    lui a2, 986895
+; RV32IP-NEXT:    addi a2, a2, 240
+; RV32IP-NEXT:    and a0, a0, a2
+; RV32IP-NEXT:    srli a0, a0, 4
+; RV32IP-NEXT:    or a0, a0, a1
+; RV32IP-NEXT:    lui a1, 209715
+; RV32IP-NEXT:    addi a1, a1, 819
+; RV32IP-NEXT:    and a1, a0, a1
+; RV32IP-NEXT:    slli a1, a1, 2
+; RV32IP-NEXT:    lui a2, 838861
+; RV32IP-NEXT:    addi a2, a2, -820
+; RV32IP-NEXT:    and a0, a0, a2
+; RV32IP-NEXT:    srli a0, a0, 2
+; RV32IP-NEXT:    or a0, a0, a1
+; RV32IP-NEXT:    lui a1, 349525
+; RV32IP-NEXT:    addi a1, a1, 1365
+; RV32IP-NEXT:    and a1, a0, a1
+; RV32IP-NEXT:    slli a1, a1, 1
+; RV32IP-NEXT:    lui a2, 699051
+; RV32IP-NEXT:    addi a2, a2, -1366
+; RV32IP-NEXT:    and a0, a0, a2
+; RV32IP-NEXT:    srli a0, a0, 1
+; RV32IP-NEXT:    or a0, a0, a1
+; RV32IP-NEXT:    ret
+;
+; RV32IPN-LABEL: bitreverse_i32:
+; RV32IPN:       # %bb.0:
+; RV32IPN-NEXT:    srli a1, a0, 8
+; RV32IPN-NEXT:    lui a2, 16
+; RV32IPN-NEXT:    addi a2, a2, -256
+; RV32IPN-NEXT:    and a1, a1, a2
+; RV32IPN-NEXT:    srli a2, a0, 24
+; RV32IPN-NEXT:    or a1, a1, a2
+; RV32IPN-NEXT:    slli a2, a0, 8
+; RV32IPN-NEXT:    lui a3, 4080
+; RV32IPN-NEXT:    and a2, a2, a3
+; RV32IPN-NEXT:    slli a0, a0, 24
+; RV32IPN-NEXT:    or a0, a0, a2
+; RV32IPN-NEXT:    or a0, a0, a1
+; RV32IPN-NEXT:    lui a1, 61681
+; RV32IPN-NEXT:    addi a1, a1, -241
+; RV32IPN-NEXT:    and a1, a0, a1
+; RV32IPN-NEXT:    slli a1, a1, 4
+; RV32IPN-NEXT:    lui a2, 986895
+; RV32IPN-NEXT:    addi a2, a2, 240
+; RV32IPN-NEXT:    and a0, a0, a2
+; RV32IPN-NEXT:    srli a0, a0, 4
+; RV32IPN-NEXT:    or a0, a0, a1
+; RV32IPN-NEXT:    lui a1, 209715
+; RV32IPN-NEXT:    addi a1, a1, 819
+; RV32IPN-NEXT:    and a1, a0, a1
+; RV32IPN-NEXT:    slli a1, a1, 2
+; RV32IPN-NEXT:    lui a2, 838861
+; RV32IPN-NEXT:    addi a2, a2, -820
+; RV32IPN-NEXT:    and a0, a0, a2
+; RV32IPN-NEXT:    srli a0, a0, 2
+; RV32IPN-NEXT:    or a0, a0, a1
+; RV32IPN-NEXT:    lui a1, 349525
+; RV32IPN-NEXT:    addi a1, a1, 1365
+; RV32IPN-NEXT:    and a1, a0, a1
+; RV32IPN-NEXT:    slli a1, a1, 1
+; RV32IPN-NEXT:    lui a2, 699051
+; RV32IPN-NEXT:    addi a2, a2, -1366
+; RV32IPN-NEXT:    and a0, a0, a2
+; RV32IPN-NEXT:    srli a0, a0, 1
+; RV32IPN-NEXT:    or a0, a0, a1
+; RV32IPN-NEXT:    ret
+;
+; RV32IBP-LABEL: bitreverse_i32:
+; RV32IBP:       # %bb.0:
+; RV32IBP-NEXT:    rev a0, a0
+; RV32IBP-NEXT:    ret
+  %ret = tail call i32 @llvm.bitreverse.i32(i32 %a)
+  ret i32 %ret
+}
+
+define i64 @bitreverse_i64(i64 %a) nounwind {
+; RV32IB-LABEL: bitreverse_i64:
+; RV32IB:       # %bb.0:
+; RV32IB-NEXT:    rev a2, a1
+; RV32IB-NEXT:    rev a1, a0
+; RV32IB-NEXT:    mv a0, a2
+; RV32IB-NEXT:    ret
+;
+; RV32IP-LABEL: bitreverse_i64:
+; RV32IP:       # %bb.0:
+; RV32IP-NEXT:    srli a2, a1, 8
+; RV32IP-NEXT:    lui a3, 16
+; RV32IP-NEXT:    addi t0, a3, -256
+; RV32IP-NEXT:    and a2, a2, t0
+; RV32IP-NEXT:    srli a4, a1, 24
+; RV32IP-NEXT:    or a2, a2, a4
+; RV32IP-NEXT:    slli a4, a1, 8
+; RV32IP-NEXT:    lui a6, 4080
+; RV32IP-NEXT:    and a4, a4, a6
+; RV32IP-NEXT:    slli a1, a1, 24
+; RV32IP-NEXT:    or a1, a1, a4
+; RV32IP-NEXT:    or a1, a1, a2
+; RV32IP-NEXT:    lui a2, 61681
+; RV32IP-NEXT:    addi t1, a2, -241
+; RV32IP-NEXT:    and a2, a1, t1
+; RV32IP-NEXT:    slli a2, a2, 4
+; RV32IP-NEXT:    lui a5, 986895
+; RV32IP-NEXT:    addi t2, a5, 240
+; RV32IP-NEXT:    and a1, a1, t2
+; RV32IP-NEXT:    srli a1, a1, 4
+; RV32IP-NEXT:    or a1, a1, a2
+; RV32IP-NEXT:    lui a2, 209715
+; RV32IP-NEXT:    addi t3, a2, 819
+; RV32IP-NEXT:    and a3, a1, t3
+; RV32IP-NEXT:    slli a3, a3, 2
+; RV32IP-NEXT:    lui a4, 838861
+; RV32IP-NEXT:    addi a4, a4, -820
+; RV32IP-NEXT:    and a1, a1, a4
+; RV32IP-NEXT:    srli a1, a1, 2
+; RV32IP-NEXT:    or a1, a1, a3
+; RV32IP-NEXT:    lui a3, 349525
+; RV32IP-NEXT:    addi a3, a3, 1365
+; RV32IP-NEXT:    and a5, a1, a3
+; RV32IP-NEXT:    slli a5, a5, 1
+; RV32IP-NEXT:    lui a2, 699051
+; RV32IP-NEXT:    addi a2, a2, -1366
+; RV32IP-NEXT:    and a1, a1, a2
+; RV32IP-NEXT:    srli a1, a1, 1
+; RV32IP-NEXT:    or a7, a1, a5
+; RV32IP-NEXT:    srli a1, a0, 8
+; RV32IP-NEXT:    and a1, a1, t0
+; RV32IP-NEXT:    srli a5, a0, 24
+; RV32IP-NEXT:    or a1, a1, a5
+; RV32IP-NEXT:    slli a5, a0, 8
+; RV32IP-NEXT:    and a5, a5, a6
+; RV32IP-NEXT:    slli a0, a0, 24
+; RV32IP-NEXT:    or a0, a0, a5
+; RV32IP-NEXT:    or a0, a0, a1
+; RV32IP-NEXT:    and a1, a0, t1
+; RV32IP-NEXT:    slli a1, a1, 4
+; RV32IP-NEXT:    and a0, a0, t2
+; RV32IP-NEXT:    srli a0, a0, 4
+; RV32IP-NEXT:    or a0, a0, a1
+; RV32IP-NEXT:    and a1, a0, t3
+; RV32IP-NEXT:    slli a1, a1, 2
+; RV32IP-NEXT:    and a0, a0, a4
+; RV32IP-NEXT:    srli a0, a0, 2
+; RV32IP-NEXT:    or a0, a0, a1
+; RV32IP-NEXT:    and a1, a0, a3
+; RV32IP-NEXT:    slli a1, a1, 1
+; RV32IP-NEXT:    and a0, a0, a2
+; RV32IP-NEXT:    srli a0, a0, 1
+; RV32IP-NEXT:    or a1, a0, a1
+; RV32IP-NEXT:    mv a0, a7
+; RV32IP-NEXT:    ret
+;
+; RV32IPN-LABEL: bitreverse_i64:
+; RV32IPN:       # %bb.0:
+; RV32IPN-NEXT:    srli a2, a1, 8
+; RV32IPN-NEXT:    lui a3, 16
+; RV32IPN-NEXT:    addi t0, a3, -256
+; RV32IPN-NEXT:    and a2, a2, t0
+; RV32IPN-NEXT:    srli a4, a1, 24
+; RV32IPN-NEXT:    or a2, a2, a4
+; RV32IPN-NEXT:    slli a4, a1, 8
+; RV32IPN-NEXT:    lui a6, 4080
+; RV32IPN-NEXT:    and a4, a4, a6
+; RV32IPN-NEXT:    slli a1, a1, 24
+; RV32IPN-NEXT:    or a1, a1, a4
+; RV32IPN-NEXT:    or a1, a1, a2
+; RV32IPN-NEXT:    lui a2, 61681
+; RV32IPN-NEXT:    addi t1, a2, -241
+; RV32IPN-NEXT:    and a2, a1, t1
+; RV32IPN-NEXT:    slli a2, a2, 4
+; RV32IPN-NEXT:    lui a5, 986895
+; RV32IPN-NEXT:    addi t2, a5, 240
+; RV32IPN-NEXT:    and a1, a1, t2
+; RV32IPN-NEXT:    srli a1, a1, 4
+; RV32IPN-NEXT:    or a1, a1, a2
+; RV32IPN-NEXT:    lui a2, 209715
+; RV32IPN-NEXT:    addi t3, a2, 819
+; RV32IPN-NEXT:    and a3, a1, t3
+; RV32IPN-NEXT:    slli a3, a3, 2
+; RV32IPN-NEXT:    lui a4, 838861
+; RV32IPN-NEXT:    addi a4, a4, -820
+; RV32IPN-NEXT:    and a1, a1, a4
+; RV32IPN-NEXT:    srli a1, a1, 2
+; RV32IPN-NEXT:    or a1, a1, a3
+; RV32IPN-NEXT:    lui a3, 349525
+; RV32IPN-NEXT:    addi a3, a3, 1365
+; RV32IPN-NEXT:    and a5, a1, a3
+; RV32IPN-NEXT:    slli a5, a5, 1
+; RV32IPN-NEXT:    lui a2, 699051
+; RV32IPN-NEXT:    addi a2, a2, -1366
+; RV32IPN-NEXT:    and a1, a1, a2
+; RV32IPN-NEXT:    srli a1, a1, 1
+; RV32IPN-NEXT:    or a7, a1, a5
+; RV32IPN-NEXT:    srli a1, a0, 8
+; RV32IPN-NEXT:    and a1, a1, t0
+; RV32IPN-NEXT:    srli a5, a0, 24
+; RV32IPN-NEXT:    or a1, a1, a5
+; RV32IPN-NEXT:    slli a5, a0, 8
+; RV32IPN-NEXT:    and a5, a5, a6
+; RV32IPN-NEXT:    slli a0, a0, 24
+; RV32IPN-NEXT:    or a0, a0, a5
+; RV32IPN-NEXT:    or a0, a0, a1
+; RV32IPN-NEXT:    and a1, a0, t1
+; RV32IPN-NEXT:    slli a1, a1, 4
+; RV32IPN-NEXT:    and a0, a0, t2
+; RV32IPN-NEXT:    srli a0, a0, 4
+; RV32IPN-NEXT:    or a0, a0, a1
+; RV32IPN-NEXT:    and a1, a0, t3
+; RV32IPN-NEXT:    slli a1, a1, 2
+; RV32IPN-NEXT:    and a0, a0, a4
+; RV32IPN-NEXT:    srli a0, a0, 2
+; RV32IPN-NEXT:    or a0, a0, a1
+; RV32IPN-NEXT:    and a1, a0, a3
+; RV32IPN-NEXT:    slli a1, a1, 1
+; RV32IPN-NEXT:    and a0, a0, a2
+; RV32IPN-NEXT:    srli a0, a0, 1
+; RV32IPN-NEXT:    or a1, a0, a1
+; RV32IPN-NEXT:    mv a0, a7
+; RV32IPN-NEXT:    ret
+;
+; RV32IBP-LABEL: bitreverse_i64:
+; RV32IBP:       # %bb.0:
+; RV32IBP-NEXT:    rev a2, a1
+; RV32IBP-NEXT:    rev a1, a0
+; RV32IBP-NEXT:    mv a0, a2
+; RV32IBP-NEXT:    ret
+  %ret = tail call i64 @llvm.bitreverse.i64(i64 %a)
+  ret i64 %ret
+}
diff --git a/llvm/test/CodeGen/RISCV/rv32zpn-bswap.ll b/llvm/test/CodeGen/RISCV/rv32zpn-bswap.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/CodeGen/RISCV/rv32zpn-bswap.ll
@@ -0,0 +1,163 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc -mtriple=riscv32 -mattr=+experimental-b -verify-machineinstrs < %s \
+; RUN:   | FileCheck %s --check-prefixes=RV32IB
+; RUN: llc -mtriple=riscv32 -mattr=+experimental-p -verify-machineinstrs < %s \
+; RUN:   | FileCheck %s --check-prefixes=RV32IP
+; RUN: llc -mtriple=riscv32 -mattr=+experimental-zpn -verify-machineinstrs < %s \
+; RUN:   | FileCheck %s --check-prefixes=RV32IPN
+; RUN: llc -mtriple=riscv32 -mattr=+experimental-b,+experimental-p -verify-machineinstrs < %s \
+; RUN:   | FileCheck %s --check-prefixes=RV32IBP
+
+declare i16 @llvm.bswap.i16(i16)
+declare i32 @llvm.bswap.i32(i32)
+declare i64 @llvm.bswap.i64(i64)
+
+define zeroext i16 @bswap_i16(i16 zeroext %a) nounwind {
+; RV32IB-LABEL: bswap_i16:
+; RV32IB:       # %bb.0:
+; RV32IB-NEXT:    rev8.h a0, a0
+; RV32IB-NEXT:    ret
+;
+; RV32IP-LABEL: bswap_i16:
+; RV32IP:       # %bb.0:
+; RV32IP-NEXT:    srli a1, a0, 8
+; RV32IP-NEXT:    slli a0, a0, 8
+; RV32IP-NEXT:    or a0, a0, a1
+; RV32IP-NEXT:    lui a1, 16
+; RV32IP-NEXT:    addi a1, a1, -1
+; RV32IP-NEXT:    and a0, a0, a1
+; RV32IP-NEXT:    ret
+;
+; RV32IPN-LABEL: bswap_i16:
+; RV32IPN:       # %bb.0:
+; RV32IPN-NEXT:    srli a1, a0, 8
+; RV32IPN-NEXT:    slli a0, a0, 8
+; RV32IPN-NEXT:    or a0, a0, a1
+; RV32IPN-NEXT:    lui a1, 16
+; RV32IPN-NEXT:    addi a1, a1, -1
+; RV32IPN-NEXT:    and a0, a0, a1
+; RV32IPN-NEXT:    ret
+;
+; RV32IBP-LABEL: bswap_i16:
+; RV32IBP:       # %bb.0:
+; RV32IBP-NEXT:    rev8.h a0, a0
+; RV32IBP-NEXT:    ret
+  %ret = tail call i16 @llvm.bswap.i16(i16 %a)
+  ret i16 %ret
+}
+
+define i32 @bswap_i32(i32 %a) nounwind {
+; RV32IB-LABEL: bswap_i32:
+; RV32IB:       # %bb.0:
+; RV32IB-NEXT:    rev8 a0, a0
+; RV32IB-NEXT:    ret
+;
+; RV32IP-LABEL: bswap_i32:
+; RV32IP:       # %bb.0:
+; RV32IP-NEXT:    srli a1, a0, 8
+; RV32IP-NEXT:    lui a2, 16
+; RV32IP-NEXT:    addi a2, a2, -256
+; RV32IP-NEXT:    and a1, a1, a2
+; RV32IP-NEXT:    srli a2, a0, 24
+; RV32IP-NEXT:    or a1, a1, a2
+; RV32IP-NEXT:    slli a2, a0, 8
+; RV32IP-NEXT:    lui a3, 4080
+; RV32IP-NEXT:    and a2, a2, a3
+; RV32IP-NEXT:    slli a0, a0, 24
+; RV32IP-NEXT:    or a0, a0, a2
+; RV32IP-NEXT:    or a0, a0, a1
+; RV32IP-NEXT:    ret
+;
+; RV32IPN-LABEL: bswap_i32:
+; RV32IPN:       # %bb.0:
+; RV32IPN-NEXT:    srli a1, a0, 8
+; RV32IPN-NEXT:    lui a2, 16
+; RV32IPN-NEXT:    addi a2, a2, -256
+; RV32IPN-NEXT:    and a1, a1, a2
+; RV32IPN-NEXT:    srli a2, a0, 24
+; RV32IPN-NEXT:    or a1, a1, a2
+; RV32IPN-NEXT:    slli a2, a0, 8
+; RV32IPN-NEXT:    lui a3, 4080
+; RV32IPN-NEXT:    and a2, a2, a3
+; RV32IPN-NEXT:    slli a0, a0, 24
+; RV32IPN-NEXT:    or a0, a0, a2
+; RV32IPN-NEXT:    or a0, a0, a1
+; RV32IPN-NEXT:    ret
+;
+; RV32IBP-LABEL: bswap_i32:
+; RV32IBP:       # %bb.0:
+; RV32IBP-NEXT:    rev8 a0, a0
+; RV32IBP-NEXT:    ret
+  %ret = tail call i32 @llvm.bswap.i32(i32 %a)
+  ret i32 %ret
+}
+
+define i64 @bswap_i64(i64 %a) nounwind {
+; RV32IB-LABEL: bswap_i64:
+; RV32IB:       # %bb.0:
+; RV32IB-NEXT:    rev8 a2, a1
+; RV32IB-NEXT:    rev8 a1, a0
+; RV32IB-NEXT:    mv a0, a2
+; RV32IB-NEXT:    ret
+;
+; RV32IP-LABEL: bswap_i64:
+; RV32IP:       # %bb.0:
+; RV32IP-NEXT:    srli a2, a1, 8
+; RV32IP-NEXT:    lui a3, 16
+; RV32IP-NEXT:    addi a3, a3, -256
+; RV32IP-NEXT:    and a2, a2, a3
+; RV32IP-NEXT:    srli a4, a1, 24
+; RV32IP-NEXT:    or a2, a2, a4
+; RV32IP-NEXT:    slli a4, a1, 8
+; RV32IP-NEXT:    lui a5, 4080
+; RV32IP-NEXT:    and a4, a4, a5
+; RV32IP-NEXT:    slli a1, a1, 24
+; RV32IP-NEXT:    or a1, a1, a4
+; RV32IP-NEXT:    or a2, a1, a2
+; RV32IP-NEXT:    srli a1, a0, 8
+; RV32IP-NEXT:    and a1, a1, a3
+; RV32IP-NEXT:    srli a3, a0, 24
+; RV32IP-NEXT:    or a1, a1, a3
+; RV32IP-NEXT:    slli a3, a0, 8
+; RV32IP-NEXT:    and a3, a3, a5
+; RV32IP-NEXT:    slli a0, a0, 24
+; RV32IP-NEXT:    or a0, a0, a3
+; RV32IP-NEXT:    or a1, a0, a1
+; RV32IP-NEXT:    mv a0, a2
+; RV32IP-NEXT:    ret
+;
+; RV32IPN-LABEL: bswap_i64:
+; RV32IPN:       # %bb.0:
+; RV32IPN-NEXT:    srli a2, a1, 8
+; RV32IPN-NEXT:    lui a3, 16
+; RV32IPN-NEXT:    addi a3, a3, -256
+; RV32IPN-NEXT:    and a2, a2, a3
+; RV32IPN-NEXT:    srli a4, a1, 24
+; RV32IPN-NEXT:    or a2, a2, a4
+; RV32IPN-NEXT:    slli a4, a1, 8
+; RV32IPN-NEXT:    lui a5, 4080
+; RV32IPN-NEXT:    and a4, a4, a5
+; RV32IPN-NEXT:    slli a1, a1, 24
+; RV32IPN-NEXT:    or a1, a1, a4
+; RV32IPN-NEXT:    or a2, a1, a2
+; RV32IPN-NEXT:    srli a1, a0, 8
+; RV32IPN-NEXT:    and a1, a1, a3
+; RV32IPN-NEXT:    srli a3, a0, 24
+; RV32IPN-NEXT:    or a1, a1, a3
+; RV32IPN-NEXT:    slli a3, a0, 8
+; RV32IPN-NEXT:    and a3, a3, a5
+; RV32IPN-NEXT:    slli a0, a0, 24
+; RV32IPN-NEXT:    or a0, a0, a3
+; RV32IPN-NEXT:    or a1, a0, a1
+; RV32IPN-NEXT:    mv a0, a2
+; RV32IPN-NEXT:    ret
+;
+; RV32IBP-LABEL: bswap_i64:
+; RV32IBP:       # %bb.0:
+; RV32IBP-NEXT:    rev8 a2, a1
+; RV32IBP-NEXT:    rev8 a1, a0
+; RV32IBP-NEXT:    mv a0, a2
+; RV32IBP-NEXT:    ret
+  %ret = tail call i64 @llvm.bswap.i64(i64 %a)
+  ret i64 %ret
+}
diff --git a/llvm/test/CodeGen/RISCV/rv64zpn-bitreverse.ll b/llvm/test/CodeGen/RISCV/rv64zpn-bitreverse.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/CodeGen/RISCV/rv64zpn-bitreverse.ll
@@ -0,0 +1,568 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc -mtriple=riscv64 -mattr=+experimental-b -verify-machineinstrs < %s \
+; RUN:   | FileCheck %s --check-prefixes=RV64IB
+; RUN: llc -mtriple=riscv64 -mattr=+experimental-p -verify-machineinstrs < %s \
+; RUN:   | FileCheck %s --check-prefixes=RV64IP
+; RUN: llc -mtriple=riscv64 -mattr=+experimental-zpn -verify-machineinstrs < %s \
+; RUN:   | FileCheck %s --check-prefixes=RV64IPN
+; RUN: llc -mtriple=riscv64 -mattr=+experimental-b,+experimental-p -verify-machineinstrs < %s \
+; RUN:   | FileCheck %s --check-prefixes=RV64IBP
+
+declare i8 @llvm.bitreverse.i8(i8)
+declare i16 @llvm.bitreverse.i16(i16)
+declare i32 @llvm.bitreverse.i32(i32)
+declare i64 @llvm.bitreverse.i64(i64)
+
+define zeroext i8 @bitreverse_i8(i8 zeroext %a) nounwind {
+; RV64IB-LABEL: bitreverse_i8:
+; RV64IB:       # %bb.0:
+; RV64IB-NEXT:    greviw a0, a0, 7
+; RV64IB-NEXT:    ret
+;
+; RV64IP-LABEL: bitreverse_i8:
+; RV64IP:       # %bb.0:
+; RV64IP-NEXT:    srli a1, a0, 4
+; RV64IP-NEXT:    andi a0, a0, 15
+; RV64IP-NEXT:    slli a0, a0, 4
+; RV64IP-NEXT:    or a0, a1, a0
+; RV64IP-NEXT:    andi a1, a0, 51
+; RV64IP-NEXT:    slli a1, a1, 2
+; RV64IP-NEXT:    andi a0, a0, 204
+; RV64IP-NEXT:    srli a0, a0, 2
+; RV64IP-NEXT:    or a0, a0, a1
+; RV64IP-NEXT:    andi a1, a0, 85
+; RV64IP-NEXT:    slli a1, a1, 1
+; RV64IP-NEXT:    andi a0, a0, 170
+; RV64IP-NEXT:    srli a0, a0, 1
+; RV64IP-NEXT:    or a0, a0, a1
+; RV64IP-NEXT:    ret
+;
+; RV64IPN-LABEL: bitreverse_i8:
+; RV64IPN:       # %bb.0:
+; RV64IPN-NEXT:    srli a1, a0, 4
+; RV64IPN-NEXT:    andi a0, a0, 15
+; RV64IPN-NEXT:    slli a0, a0, 4
+; RV64IPN-NEXT:    or a0, a1, a0
+; RV64IPN-NEXT:    andi a1, a0, 51
+; RV64IPN-NEXT:    slli a1, a1, 2
+; RV64IPN-NEXT:    andi a0, a0, 204
+; RV64IPN-NEXT:    srli a0, a0, 2
+; RV64IPN-NEXT:    or a0, a0, a1
+; RV64IPN-NEXT:    andi a1, a0, 85
+; RV64IPN-NEXT:    slli a1, a1, 1
+; RV64IPN-NEXT:    andi a0, a0, 170
+; RV64IPN-NEXT:    srli a0, a0, 1
+; RV64IPN-NEXT:    or a0, a0, a1
+; RV64IPN-NEXT:    ret
+;
+; RV64IBP-LABEL: bitreverse_i8:
+; RV64IBP:       # %bb.0:
+; RV64IBP-NEXT:    greviw a0, a0, 7
+; RV64IBP-NEXT:    ret
+  %ret = tail call i8 @llvm.bitreverse.i8(i8 %a)
+  ret i8 %ret
+}
+
+define zeroext i16 @bitreverse_i16(i16 zeroext %a) nounwind {
+; RV64IB-LABEL: bitreverse_i16:
+; RV64IB:       # %bb.0:
+; RV64IB-NEXT:    greviw a0, a0, 15
+; RV64IB-NEXT:    ret
+;
+; RV64IP-LABEL: bitreverse_i16:
+; RV64IP:       # %bb.0:
+; RV64IP-NEXT:    srli a1, a0, 8
+; RV64IP-NEXT:    slli a0, a0, 8
+; RV64IP-NEXT:    or a0, a0, a1
+; RV64IP-NEXT:    lui a1, 1
+; RV64IP-NEXT:    addiw a1, a1, -241
+; RV64IP-NEXT:    and a1, a0, a1
+; RV64IP-NEXT:    slli a1, a1, 4
+; RV64IP-NEXT:    lui a2, 15
+; RV64IP-NEXT:    addiw a2, a2, 240
+; RV64IP-NEXT:    and a0, a0, a2
+; RV64IP-NEXT:    srli a0, a0, 4
+; RV64IP-NEXT:    or a0, a0, a1
+; RV64IP-NEXT:    lui a1, 3
+; RV64IP-NEXT:    addiw a1, a1, 819
+; RV64IP-NEXT:    and a1, a0, a1
+; RV64IP-NEXT:    slli a1, a1, 2
+; RV64IP-NEXT:    lui a2, 13
+; RV64IP-NEXT:    addiw a2, a2, -820
+; RV64IP-NEXT:    and a0, a0, a2
+; RV64IP-NEXT:    srli a0, a0, 2
+; RV64IP-NEXT:    or a0, a0, a1
+; RV64IP-NEXT:    lui a1, 5
+; RV64IP-NEXT:    addiw a1, a1, 1365
+; RV64IP-NEXT:    and a1, a0, a1
+; RV64IP-NEXT:    slli a1, a1, 1
+; RV64IP-NEXT:    lui a2, 11
+; RV64IP-NEXT:    addiw a2, a2, -1366
+; RV64IP-NEXT:    and a0, a0, a2
+; RV64IP-NEXT:    srli a0, a0, 1
+; RV64IP-NEXT:    or a0, a0, a1
+; RV64IP-NEXT:    ret
+;
+; RV64IPN-LABEL: bitreverse_i16:
+; RV64IPN:       # %bb.0:
+; RV64IPN-NEXT:    srli a1, a0, 8
+; RV64IPN-NEXT:    slli a0, a0, 8
+; RV64IPN-NEXT:    or a0, a0, a1
+; RV64IPN-NEXT:    lui a1, 1
+; RV64IPN-NEXT:    addiw a1, a1, -241
+; RV64IPN-NEXT:    and a1, a0, a1
+; RV64IPN-NEXT:    slli a1, a1, 4
+; RV64IPN-NEXT:    lui a2, 15
+; RV64IPN-NEXT:    addiw a2, a2, 240
+; RV64IPN-NEXT:    and a0, a0, a2
+; RV64IPN-NEXT:    srli a0, a0, 4
+; RV64IPN-NEXT:    or a0, a0, a1
+; RV64IPN-NEXT:    lui a1, 3
+; RV64IPN-NEXT:    addiw a1, a1, 819
+; RV64IPN-NEXT:    and a1, a0, a1
+; RV64IPN-NEXT:    slli a1, a1, 2
+; RV64IPN-NEXT:    lui a2, 13
+; RV64IPN-NEXT:    addiw a2, a2, -820
+; RV64IPN-NEXT:    and a0, a0, a2
+; RV64IPN-NEXT:    srli a0, a0, 2
+; RV64IPN-NEXT:    or a0, a0, a1
+; RV64IPN-NEXT:    lui a1, 5
+; RV64IPN-NEXT:    addiw a1, a1, 1365
+; RV64IPN-NEXT:    and a1, a0, a1
+; RV64IPN-NEXT:    slli a1, a1, 1
+; RV64IPN-NEXT:    lui a2, 11
+; RV64IPN-NEXT:    addiw a2, a2, -1366
+; RV64IPN-NEXT:    and a0, a0, a2
+; RV64IPN-NEXT:    srli a0, a0, 1
+; RV64IPN-NEXT:    or a0, a0, a1
+; RV64IPN-NEXT:    ret
+;
+; RV64IBP-LABEL: bitreverse_i16:
+; RV64IBP:       # %bb.0:
+; RV64IBP-NEXT:    greviw a0, a0, 15
+; RV64IBP-NEXT:    ret
+  %ret = tail call i16 @llvm.bitreverse.i16(i16 %a)
+  ret i16 %ret
+}
+
+define signext i32 @bitreverse_i32(i32 signext %a) nounwind {
+; RV64IB-LABEL: bitreverse_i32:
+; RV64IB:       # %bb.0:
+; RV64IB-NEXT:    greviw a0, a0, 31
+; RV64IB-NEXT:    ret
+;
+; RV64IP-LABEL: bitreverse_i32:
+; RV64IP:       # %bb.0:
+; RV64IP-NEXT:    srliw a1, a0, 8
+; RV64IP-NEXT:    lui a2, 16
+; RV64IP-NEXT:    addiw a2, a2, -256
+; RV64IP-NEXT:    and a1, a1, a2
+; RV64IP-NEXT:    srliw a2, a0, 24
+; RV64IP-NEXT:    or a1, a1, a2
+; RV64IP-NEXT:    slli a2, a0, 8
+; RV64IP-NEXT:    lui a3, 4080
+; RV64IP-NEXT:    and a2, a2, a3
+; RV64IP-NEXT:    slli a0, a0, 24
+; RV64IP-NEXT:    or a0, a0, a2
+; RV64IP-NEXT:    or a0, a0, a1
+; RV64IP-NEXT:    lui a1, 61681
+; RV64IP-NEXT:    addiw a1, a1, -241
+; RV64IP-NEXT:    and a1, a0, a1
+; RV64IP-NEXT:    slli a1, a1, 4
+; RV64IP-NEXT:    lui a2, 241
+; RV64IP-NEXT:    addiw a2, a2, -241
+; RV64IP-NEXT:    slli a2, a2, 12
+; RV64IP-NEXT:    addi a2, a2, 240
+; RV64IP-NEXT:    and a0, a0, a2
+; RV64IP-NEXT:    srli a0, a0, 4
+; RV64IP-NEXT:    or a0, a0, a1
+; RV64IP-NEXT:    lui a1, 209715
+; RV64IP-NEXT:    addiw a1, a1, 819
+; RV64IP-NEXT:    and a1, a0, a1
+; RV64IP-NEXT:    slli a1, a1, 2
+; RV64IP-NEXT:    lui a2, 838861
+; RV64IP-NEXT:    addiw a2, a2, -820
+; RV64IP-NEXT:    and a0, a0, a2
+; RV64IP-NEXT:    srli a0, a0, 2
+; RV64IP-NEXT:    or a0, a0, a1
+; RV64IP-NEXT:    lui a1, 349525
+; RV64IP-NEXT:    addiw a1, a1, 1365
+; RV64IP-NEXT:    and a1, a0, a1
+; RV64IP-NEXT:    slli a1, a1, 1
+; RV64IP-NEXT:    lui a2, 699051
+; RV64IP-NEXT:    addiw a2, a2, -1366
+; RV64IP-NEXT:    and a0, a0, a2
+; RV64IP-NEXT:    srli a0, a0, 1
+; RV64IP-NEXT:    or a0, a0, a1
+; RV64IP-NEXT:    sext.w a0, a0
+; RV64IP-NEXT:    ret
+;
+; RV64IPN-LABEL: bitreverse_i32:
+; RV64IPN:       # %bb.0:
+; RV64IPN-NEXT:    srliw a1, a0, 8
+; RV64IPN-NEXT:    lui a2, 16
+; RV64IPN-NEXT:    addiw a2, a2, -256
+; RV64IPN-NEXT:    and a1, a1, a2
+; RV64IPN-NEXT:    srliw a2, a0, 24
+; RV64IPN-NEXT:    or a1, a1, a2
+; RV64IPN-NEXT:    slli a2, a0, 8
+; RV64IPN-NEXT:    lui a3, 4080
+; RV64IPN-NEXT:    and a2, a2, a3
+; RV64IPN-NEXT:    slli a0, a0, 24
+; RV64IPN-NEXT:    or a0, a0, a2
+; RV64IPN-NEXT:    or a0, a0, a1
+; RV64IPN-NEXT:    lui a1, 61681
+; RV64IPN-NEXT:    addiw a1, a1, -241
+; RV64IPN-NEXT:    and a1, a0, a1
+; RV64IPN-NEXT:    slli a1, a1, 4
+; RV64IPN-NEXT:    lui a2, 241
+; RV64IPN-NEXT:    addiw a2, a2, -241
+; RV64IPN-NEXT:    slli a2, a2, 12
+; RV64IPN-NEXT:    addi a2, a2, 240
+; RV64IPN-NEXT:    and a0, a0, a2
+; RV64IPN-NEXT:    srli a0, a0, 4
+; RV64IPN-NEXT:    or a0, a0, a1
+; RV64IPN-NEXT:    lui a1, 209715
+; RV64IPN-NEXT:    addiw a1, a1, 819
+; RV64IPN-NEXT:    and a1, a0, a1
+; RV64IPN-NEXT:    slli a1, a1, 2
+; RV64IPN-NEXT:    lui a2, 838861
+; RV64IPN-NEXT:    addiw a2, a2, -820
+; RV64IPN-NEXT:    and a0, a0, a2
+; RV64IPN-NEXT:    srli a0, a0, 2
+; RV64IPN-NEXT:    or a0, a0, a1
+; RV64IPN-NEXT:    lui a1, 349525
+; RV64IPN-NEXT:    addiw a1, a1, 1365
+; RV64IPN-NEXT:    and a1, a0, a1
+; RV64IPN-NEXT:    slli a1, a1, 1
+; RV64IPN-NEXT:    lui a2, 699051
+; RV64IPN-NEXT:    addiw a2, a2, -1366
+; RV64IPN-NEXT:    and a0, a0, a2
+; RV64IPN-NEXT:    srli a0, a0, 1
+; RV64IPN-NEXT:    or a0, a0, a1
+; RV64IPN-NEXT:    sext.w a0, a0
+; RV64IPN-NEXT:    ret
+;
+; RV64IBP-LABEL: bitreverse_i32:
+; RV64IBP:       # %bb.0:
+; RV64IBP-NEXT:    greviw a0, a0, 31
+; RV64IBP-NEXT:    ret
+  %ret = tail call i32 @llvm.bitreverse.i32(i32 %a)
+  ret i32 %ret
+}
+
+; Similar to bitreverse32 but the result is not sign extended.
+define void @bitreverse_i32_nosext(i32 signext %a, i32* %x) nounwind {
+; RV64IB-LABEL: bitreverse_i32_nosext:
+; RV64IB:       # %bb.0:
+; RV64IB-NEXT:    greviw a0, a0, 31
+; RV64IB-NEXT:    sw a0, 0(a1)
+; RV64IB-NEXT:    ret
+;
+; RV64IP-LABEL: bitreverse_i32_nosext:
+; RV64IP:       # %bb.0:
+; RV64IP-NEXT:    srliw a2, a0, 8
+; RV64IP-NEXT:    lui a3, 16
+; RV64IP-NEXT:    addiw a3, a3, -256
+; RV64IP-NEXT:    and a2, a2, a3
+; RV64IP-NEXT:    srliw a3, a0, 24
+; RV64IP-NEXT:    or a2, a2, a3
+; RV64IP-NEXT:    slli a3, a0, 8
+; RV64IP-NEXT:    lui a4, 4080
+; RV64IP-NEXT:    and a3, a3, a4
+; RV64IP-NEXT:    slli a0, a0, 24
+; RV64IP-NEXT:    or a0, a0, a3
+; RV64IP-NEXT:    or a0, a0, a2
+; RV64IP-NEXT:    lui a2, 61681
+; RV64IP-NEXT:    addiw a2, a2, -241
+; RV64IP-NEXT:    and a2, a0, a2
+; RV64IP-NEXT:    slli a2, a2, 4
+; RV64IP-NEXT:    lui a3, 241
+; RV64IP-NEXT:    addiw a3, a3, -241
+; RV64IP-NEXT:    slli a3, a3, 12
+; RV64IP-NEXT:    addi a3, a3, 240
+; RV64IP-NEXT:    and a0, a0, a3
+; RV64IP-NEXT:    srli a0, a0, 4
+; RV64IP-NEXT:    or a0, a0, a2
+; RV64IP-NEXT:    lui a2, 209715
+; RV64IP-NEXT:    addiw a2, a2, 819
+; RV64IP-NEXT:    and a2, a0, a2
+; RV64IP-NEXT:    slli a2, a2, 2
+; RV64IP-NEXT:    lui a3, 838861
+; RV64IP-NEXT:    addiw a3, a3, -820
+; RV64IP-NEXT:    and a0, a0, a3
+; RV64IP-NEXT:    srli a0, a0, 2
+; RV64IP-NEXT:    or a0, a0, a2
+; RV64IP-NEXT:    lui a2, 349525
+; RV64IP-NEXT:    addiw a2, a2, 1365
+; RV64IP-NEXT:    and a2, a0, a2
+; RV64IP-NEXT:    slli a2, a2, 1
+; RV64IP-NEXT:    lui a3, 699051
+; RV64IP-NEXT:    addiw a3, a3, -1366
+; RV64IP-NEXT:    and a0, a0, a3
+; RV64IP-NEXT:    srli a0, a0, 1
+; RV64IP-NEXT:    or a0, a0, a2
+; RV64IP-NEXT:    sw a0, 0(a1)
+; RV64IP-NEXT:    ret
+;
+; RV64IPN-LABEL: bitreverse_i32_nosext:
+; RV64IPN:       # %bb.0:
+; RV64IPN-NEXT:    srliw a2, a0, 8
+; RV64IPN-NEXT:    lui a3, 16
+; RV64IPN-NEXT:    addiw a3, a3, -256
+; RV64IPN-NEXT:    and a2, a2, a3
+; RV64IPN-NEXT:    srliw a3, a0, 24
+; RV64IPN-NEXT:    or a2, a2, a3
+; RV64IPN-NEXT:    slli a3, a0, 8
+; RV64IPN-NEXT:    lui a4, 4080
+; RV64IPN-NEXT:    and a3, a3, a4
+; RV64IPN-NEXT:    slli a0, a0, 24
+; RV64IPN-NEXT:    or a0, a0, a3
+; RV64IPN-NEXT:    or a0, a0, a2
+; RV64IPN-NEXT:    lui a2, 61681
+; RV64IPN-NEXT:    addiw a2, a2, -241
+; RV64IPN-NEXT:    and a2, a0, a2
+; RV64IPN-NEXT:    slli a2, a2, 4
+; RV64IPN-NEXT:    lui a3, 241
+; RV64IPN-NEXT:    addiw a3, a3, -241
+; RV64IPN-NEXT:    slli a3, a3, 12
+; RV64IPN-NEXT:    addi a3, a3, 240
+; RV64IPN-NEXT:    and a0, a0, a3
+; RV64IPN-NEXT:    srli a0, a0, 4
+; RV64IPN-NEXT:    or a0, a0, a2
+; RV64IPN-NEXT:    lui a2, 209715
+; RV64IPN-NEXT:    addiw a2, a2, 819
+; RV64IPN-NEXT:    and a2, a0, a2
+; RV64IPN-NEXT:    slli a2, a2, 2
+; RV64IPN-NEXT:    lui a3, 838861
+; RV64IPN-NEXT:    addiw a3, a3, -820
+; RV64IPN-NEXT:    and a0, a0, a3
+; RV64IPN-NEXT:    srli a0, a0, 2
+; RV64IPN-NEXT:    or a0, a0, a2
+; RV64IPN-NEXT:    lui a2, 349525
+; RV64IPN-NEXT:    addiw a2, a2, 1365
+; RV64IPN-NEXT:    and a2, a0, a2
+; RV64IPN-NEXT:    slli a2, a2, 1
+; RV64IPN-NEXT:    lui a3, 699051
+; RV64IPN-NEXT:    addiw a3, a3, -1366
+; RV64IPN-NEXT:    and a0, a0, a3
+; RV64IPN-NEXT:    srli a0, a0, 1
+; RV64IPN-NEXT:    or a0, a0, a2
+; RV64IPN-NEXT:    sw a0, 0(a1)
+; RV64IPN-NEXT:    ret
+;
+; RV64IBP-LABEL: bitreverse_i32_nosext:
+; RV64IBP:       # %bb.0:
+; RV64IBP-NEXT:    greviw a0, a0, 31
+; RV64IBP-NEXT:    sw a0, 0(a1)
+; RV64IBP-NEXT:    ret
+  %ret = tail call i32 @llvm.bitreverse.i32(i32 %a)
+  store i32 %ret, i32* %x
+  ret void
+}
+
+define i64 @bitreverse_i64(i64 %a) nounwind {
+; RV64IB-LABEL: bitreverse_i64:
+; RV64IB:       # %bb.0:
+; RV64IB-NEXT:    rev a0, a0
+; RV64IB-NEXT:    ret
+;
+; RV64IP-LABEL: bitreverse_i64:
+; RV64IP:       # %bb.0:
+; RV64IP-NEXT:    srli a1, a0, 24
+; RV64IP-NEXT:    lui a2, 4080
+; RV64IP-NEXT:    and a1, a1, a2
+; RV64IP-NEXT:    srli a2, a0, 8
+; RV64IP-NEXT:    addi a3, zero, 255
+; RV64IP-NEXT:    slli a4, a3, 24
+; RV64IP-NEXT:    and a2, a2, a4
+; RV64IP-NEXT:    or a1, a2, a1
+; RV64IP-NEXT:    srli a2, a0, 40
+; RV64IP-NEXT:    lui a4, 16
+; RV64IP-NEXT:    addiw a4, a4, -256
+; RV64IP-NEXT:    and a2, a2, a4
+; RV64IP-NEXT:    srli a4, a0, 56
+; RV64IP-NEXT:    or a2, a2, a4
+; RV64IP-NEXT:    or a1, a1, a2
+; RV64IP-NEXT:    slli a2, a0, 8
+; RV64IP-NEXT:    slli a4, a3, 32
+; RV64IP-NEXT:    and a2, a2, a4
+; RV64IP-NEXT:    slli a4, a0, 24
+; RV64IP-NEXT:    slli a5, a3, 40
+; RV64IP-NEXT:    and a4, a4, a5
+; RV64IP-NEXT:    or a2, a4, a2
+; RV64IP-NEXT:    slli a4, a0, 40
+; RV64IP-NEXT:    slli a3, a3, 48
+; RV64IP-NEXT:    and a3, a4, a3
+; RV64IP-NEXT:    slli a0, a0, 56
+; RV64IP-NEXT:    or a0, a0, a3
+; RV64IP-NEXT:    or a0, a0, a2
+; RV64IP-NEXT:    or a0, a0, a1
+; RV64IP-NEXT:    lui a1, 3855
+; RV64IP-NEXT:    addiw a1, a1, 241
+; RV64IP-NEXT:    slli a1, a1, 12
+; RV64IP-NEXT:    addi a1, a1, -241
+; RV64IP-NEXT:    slli a1, a1, 12
+; RV64IP-NEXT:    addi a1, a1, 241
+; RV64IP-NEXT:    slli a1, a1, 12
+; RV64IP-NEXT:    addi a1, a1, -241
+; RV64IP-NEXT:    and a1, a0, a1
+; RV64IP-NEXT:    slli a1, a1, 4
+; RV64IP-NEXT:    lui a2, 1044721
+; RV64IP-NEXT:    addiw a2, a2, -241
+; RV64IP-NEXT:    slli a2, a2, 12
+; RV64IP-NEXT:    addi a2, a2, 241
+; RV64IP-NEXT:    slli a2, a2, 12
+; RV64IP-NEXT:    addi a2, a2, -241
+; RV64IP-NEXT:    slli a2, a2, 12
+; RV64IP-NEXT:    addi a2, a2, 240
+; RV64IP-NEXT:    and a0, a0, a2
+; RV64IP-NEXT:    srli a0, a0, 4
+; RV64IP-NEXT:    or a0, a0, a1
+; RV64IP-NEXT:    lui a1, 13107
+; RV64IP-NEXT:    addiw a1, a1, 819
+; RV64IP-NEXT:    slli a1, a1, 12
+; RV64IP-NEXT:    addi a1, a1, 819
+; RV64IP-NEXT:    slli a1, a1, 12
+; RV64IP-NEXT:    addi a1, a1, 819
+; RV64IP-NEXT:    slli a1, a1, 12
+; RV64IP-NEXT:    addi a1, a1, 819
+; RV64IP-NEXT:    and a1, a0, a1
+; RV64IP-NEXT:    slli a1, a1, 2
+; RV64IP-NEXT:    lui a2, 1035469
+; RV64IP-NEXT:    addiw a2, a2, -819
+; RV64IP-NEXT:    slli a2, a2, 12
+; RV64IP-NEXT:    addi a2, a2, -819
+; RV64IP-NEXT:    slli a2, a2, 12
+; RV64IP-NEXT:    addi a2, a2, -819
+; RV64IP-NEXT:    slli a2, a2, 12
+; RV64IP-NEXT:    addi a2, a2, -820
+; RV64IP-NEXT:    and a0, a0, a2
+; RV64IP-NEXT:    srli a0, a0, 2
+; RV64IP-NEXT:    or a0, a0, a1
+; RV64IP-NEXT:    lui a1, 21845
+; RV64IP-NEXT:    addiw a1, a1, 1365
+; RV64IP-NEXT:    slli a1, a1, 12
+; RV64IP-NEXT:    addi a1, a1, 1365
+; RV64IP-NEXT:    slli a1, a1, 12
+; RV64IP-NEXT:    addi a1, a1, 1365
+; RV64IP-NEXT:    slli a1, a1, 12
+; RV64IP-NEXT:    addi a1, a1, 1365
+; RV64IP-NEXT:    and a1, a0, a1
+; RV64IP-NEXT:    slli a1, a1, 1
+; RV64IP-NEXT:    lui a2, 1026731
+; RV64IP-NEXT:    addiw a2, a2, -1365
+; RV64IP-NEXT:    slli a2, a2, 12
+; RV64IP-NEXT:    addi a2, a2, -1365
+; RV64IP-NEXT:    slli a2, a2, 12
+; RV64IP-NEXT:    addi a2, a2, -1365
+; RV64IP-NEXT:    slli a2, a2, 12
+; RV64IP-NEXT:    addi a2, a2, -1366
+; RV64IP-NEXT:    and a0, a0, a2
+; RV64IP-NEXT:    srli a0, a0, 1
+; RV64IP-NEXT:    or a0, a0, a1
+; RV64IP-NEXT:    ret
+;
+; RV64IPN-LABEL: bitreverse_i64:
+; RV64IPN:       # %bb.0:
+; RV64IPN-NEXT:    srli a1, a0, 24
+; RV64IPN-NEXT:    lui a2, 4080
+; RV64IPN-NEXT:    and a1, a1, a2
+; RV64IPN-NEXT:    srli a2, a0, 8
+; RV64IPN-NEXT:    addi a3, zero, 255
+; RV64IPN-NEXT:    slli a4, a3, 24
+; RV64IPN-NEXT:    and a2, a2, a4
+; RV64IPN-NEXT:    or a1, a2, a1
+; RV64IPN-NEXT:    srli a2, a0, 40
+; RV64IPN-NEXT:    lui a4, 16
+; RV64IPN-NEXT:    addiw a4, a4, -256
+; RV64IPN-NEXT:    and a2, a2, a4
+; RV64IPN-NEXT:    srli a4, a0, 56
+; RV64IPN-NEXT:    or a2, a2, a4
+; RV64IPN-NEXT:    or a1, a1, a2
+; RV64IPN-NEXT:    slli a2, a0, 8
+; RV64IPN-NEXT:    slli a4, a3, 32
+; RV64IPN-NEXT:    and a2, a2, a4
+; RV64IPN-NEXT:    slli a4, a0, 24
+; RV64IPN-NEXT:    slli a5, a3, 40
+; RV64IPN-NEXT:    and a4, a4, a5
+; RV64IPN-NEXT:    or a2, a4, a2
+; RV64IPN-NEXT:    slli a4, a0, 40
+; RV64IPN-NEXT:    slli a3, a3, 48
+; RV64IPN-NEXT:    and a3, a4, a3
+; RV64IPN-NEXT:    slli a0, a0, 56
+; RV64IPN-NEXT:    or a0, a0, a3
+; RV64IPN-NEXT:    or a0, a0, a2
+; RV64IPN-NEXT:    or a0, a0, a1
+; RV64IPN-NEXT:    lui a1, 3855
+; RV64IPN-NEXT:    addiw a1, a1, 241
+; RV64IPN-NEXT:    slli a1, a1, 12
+; RV64IPN-NEXT:    addi a1, a1, -241
+; RV64IPN-NEXT:    slli a1, a1, 12
+; RV64IPN-NEXT:    addi a1, a1, 241
+; RV64IPN-NEXT:    slli a1, a1, 12
+; RV64IPN-NEXT:    addi a1, a1, -241
+; RV64IPN-NEXT:    and a1, a0, a1
+; RV64IPN-NEXT:    slli a1, a1, 4
+; RV64IPN-NEXT:    lui a2, 1044721
+; RV64IPN-NEXT:    addiw a2, a2, -241
+; RV64IPN-NEXT:    slli a2, a2, 12
+; RV64IPN-NEXT:    addi a2, a2, 241
+; RV64IPN-NEXT:    slli a2, a2, 12
+; RV64IPN-NEXT:    addi a2, a2, -241
+; RV64IPN-NEXT:    slli a2, a2, 12
+; RV64IPN-NEXT:    addi a2, a2, 240
+; RV64IPN-NEXT:    and a0, a0, a2
+; RV64IPN-NEXT:    srli a0, a0, 4
+; RV64IPN-NEXT:    or a0, a0, a1
+; RV64IPN-NEXT:    lui a1, 13107
+; RV64IPN-NEXT:    addiw a1, a1, 819
+; RV64IPN-NEXT:    slli a1, a1, 12
+; RV64IPN-NEXT:    addi a1, a1, 819
+; RV64IPN-NEXT:    slli a1, a1, 12
+; RV64IPN-NEXT:    addi a1, a1, 819
+; RV64IPN-NEXT:    slli a1, a1, 12
+; RV64IPN-NEXT:    addi a1, a1, 819
+; RV64IPN-NEXT:    and a1, a0, a1
+; RV64IPN-NEXT:    slli a1, a1, 2
+; RV64IPN-NEXT:    lui a2, 1035469
+; RV64IPN-NEXT:    addiw a2, a2, -819
+; RV64IPN-NEXT:    slli a2, a2, 12
+; RV64IPN-NEXT:    addi a2, a2, -819
+; RV64IPN-NEXT:    slli a2, a2, 12
+; RV64IPN-NEXT:    addi a2, a2, -819
+; RV64IPN-NEXT:    slli a2, a2, 12
+; RV64IPN-NEXT:    addi a2, a2, -820
+; RV64IPN-NEXT:    and a0, a0, a2
+; RV64IPN-NEXT:    srli a0, a0, 2
+; RV64IPN-NEXT:    or a0, a0, a1
+; RV64IPN-NEXT:    lui a1, 21845
+; RV64IPN-NEXT:    addiw a1, a1, 1365
+; RV64IPN-NEXT:    slli a1, a1, 12
+; RV64IPN-NEXT:    addi a1, a1, 1365
+; RV64IPN-NEXT:    slli a1, a1, 12
+; RV64IPN-NEXT:    addi a1, a1, 1365
+; RV64IPN-NEXT:    slli a1, a1, 12
+; RV64IPN-NEXT:    addi a1, a1, 1365
+; RV64IPN-NEXT:    and a1, a0, a1
+; RV64IPN-NEXT:    slli a1, a1, 1
+; RV64IPN-NEXT:    lui a2, 1026731
+; RV64IPN-NEXT:    addiw a2, a2, -1365
+; RV64IPN-NEXT:    slli a2, a2, 12
+; RV64IPN-NEXT:    addi a2, a2, -1365
+; RV64IPN-NEXT:    slli a2, a2, 12
+; RV64IPN-NEXT:    addi a2, a2, -1365
+; RV64IPN-NEXT:    slli a2, a2, 12
+; RV64IPN-NEXT:    addi a2, a2, -1366
+; RV64IPN-NEXT:    and a0, a0, a2
+; RV64IPN-NEXT:    srli a0, a0, 1
+; RV64IPN-NEXT:    or a0, a0, a1
+; RV64IPN-NEXT:    ret
+;
+; RV64IBP-LABEL: bitreverse_i64:
+; RV64IBP:       # %bb.0:
+; RV64IBP-NEXT:    rev a0, a0
+; RV64IBP-NEXT:    ret
+  %ret = tail call i64 @llvm.bitreverse.i64(i64 %a)
+  ret i64 %ret
+}
diff --git a/llvm/test/CodeGen/RISCV/rv64zpn-bswap.ll b/llvm/test/CodeGen/RISCV/rv64zpn-bswap.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/CodeGen/RISCV/rv64zpn-bswap.ll
@@ -0,0 +1,227 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc -mtriple=riscv64 -mattr=+experimental-b -verify-machineinstrs < %s \
+; RUN:   | FileCheck %s --check-prefixes=RV64IB
+; RUN: llc -mtriple=riscv64 -mattr=+experimental-p -verify-machineinstrs < %s \
+; RUN:   | FileCheck %s --check-prefixes=RV64IP
+; RUN: llc -mtriple=riscv64 -mattr=+experimental-zpn -verify-machineinstrs < %s \
+; RUN:   | FileCheck %s --check-prefixes=RV64IPN
+; RUN: llc -mtriple=riscv64 -mattr=+experimental-b,+experimental-p -verify-machineinstrs < %s \
+; RUN:   | FileCheck %s --check-prefixes=RV64IBP
+
+declare i16 @llvm.bswap.i16(i16)
+declare i32 @llvm.bswap.i32(i32)
+declare i64 @llvm.bswap.i64(i64)
+
+define zeroext i16 @bswap_i16(i16 zeroext %a) nounwind {
+; RV64IB-LABEL: bswap_i16:
+; RV64IB:       # %bb.0:
+; RV64IB-NEXT:    greviw a0, a0, 8
+; RV64IB-NEXT:    ret
+;
+; RV64IP-LABEL: bswap_i16:
+; RV64IP:       # %bb.0:
+; RV64IP-NEXT:    srli a1, a0, 8
+; RV64IP-NEXT:    slli a0, a0, 8
+; RV64IP-NEXT:    or a0, a0, a1
+; RV64IP-NEXT:    lui a1, 16
+; RV64IP-NEXT:    addiw a1, a1, -1
+; RV64IP-NEXT:    and a0, a0, a1
+; RV64IP-NEXT:    ret
+;
+; RV64IPN-LABEL: bswap_i16:
+; RV64IPN:       # %bb.0:
+; RV64IPN-NEXT:    srli a1, a0, 8
+; RV64IPN-NEXT:    slli a0, a0, 8
+; RV64IPN-NEXT:    or a0, a0, a1
+; RV64IPN-NEXT:    lui a1, 16
+; RV64IPN-NEXT:    addiw a1, a1, -1
+; RV64IPN-NEXT:    and a0, a0, a1
+; RV64IPN-NEXT:    ret
+;
+; RV64IBP-LABEL: bswap_i16:
+; RV64IBP:       # %bb.0:
+; RV64IBP-NEXT:    greviw a0, a0, 8
+; RV64IBP-NEXT:    ret
+  %ret = tail call i16 @llvm.bswap.i16(i16 %a)
+  ret i16 %ret
+}
+
+define signext i32 @bswap_i32(i32 signext %a) nounwind {
+; RV64IB-LABEL: bswap_i32:
+; RV64IB:       # %bb.0:
+; RV64IB-NEXT:    greviw a0, a0, 24
+; RV64IB-NEXT:    ret
+;
+; RV64IP-LABEL: bswap_i32:
+; RV64IP:       # %bb.0:
+; RV64IP-NEXT:    srliw a1, a0, 8
+; RV64IP-NEXT:    lui a2, 16
+; RV64IP-NEXT:    addiw a2, a2, -256
+; RV64IP-NEXT:    and a1, a1, a2
+; RV64IP-NEXT:    srliw a2, a0, 24
+; RV64IP-NEXT:    or a1, a1, a2
+; RV64IP-NEXT:    slli a2, a0, 8
+; RV64IP-NEXT:    lui a3, 4080
+; RV64IP-NEXT:    and a2, a2, a3
+; RV64IP-NEXT:    slli a0, a0, 24
+; RV64IP-NEXT:    or a0, a0, a2
+; RV64IP-NEXT:    or a0, a0, a1
+; RV64IP-NEXT:    sext.w a0, a0
+; RV64IP-NEXT:    ret
+;
+; RV64IPN-LABEL: bswap_i32:
+; RV64IPN:       # %bb.0:
+; RV64IPN-NEXT:    srliw a1, a0, 8
+; RV64IPN-NEXT:    lui a2, 16
+; RV64IPN-NEXT:    addiw a2, a2, -256
+; RV64IPN-NEXT:    and a1, a1, a2
+; RV64IPN-NEXT:    srliw a2, a0, 24
+; RV64IPN-NEXT:    or a1, a1, a2
+; RV64IPN-NEXT:    slli a2, a0, 8
+; RV64IPN-NEXT:    lui a3, 4080
+; RV64IPN-NEXT:    and a2, a2, a3
+; RV64IPN-NEXT:    slli a0, a0, 24
+; RV64IPN-NEXT:    or a0, a0, a2
+; RV64IPN-NEXT:    or a0, a0, a1
+; RV64IPN-NEXT:    sext.w a0, a0
+; RV64IPN-NEXT:    ret
+;
+; RV64IBP-LABEL: bswap_i32:
+; RV64IBP:       # %bb.0:
+; RV64IBP-NEXT:    greviw a0, a0, 24
+; RV64IBP-NEXT:    ret
+  %ret = tail call i32 @llvm.bswap.i32(i32 %a)
+  ret i32 %ret
+}
+
+; Similar to bswap_i32 but the result is not sign extended.
+define void @bswap_i32_nosext(i32 signext %a, i32* %x) nounwind {
+; RV64IB-LABEL: bswap_i32_nosext:
+; RV64IB:       # %bb.0:
+; RV64IB-NEXT:    greviw a0, a0, 24
+; RV64IB-NEXT:    sw a0, 0(a1)
+; RV64IB-NEXT:    ret
+;
+; RV64IP-LABEL: bswap_i32_nosext:
+; RV64IP:       # %bb.0:
+; RV64IP-NEXT:    srliw a2, a0, 8
+; RV64IP-NEXT:    lui a3, 16
+; RV64IP-NEXT:    addiw a3, a3, -256
+; RV64IP-NEXT:    and a2, a2, a3
+; RV64IP-NEXT:    srliw a3, a0, 24
+; RV64IP-NEXT:    or a2, a2, a3
+; RV64IP-NEXT:    slli a3, a0, 8
+; RV64IP-NEXT:    lui a4, 4080
+; RV64IP-NEXT:    and a3, a3, a4
+; RV64IP-NEXT:    slli a0, a0, 24
+; RV64IP-NEXT:    or a0, a0, a3
+; RV64IP-NEXT:    or a0, a0, a2
+; RV64IP-NEXT:    sw a0, 0(a1)
+; RV64IP-NEXT:    ret
+;
+; RV64IPN-LABEL: bswap_i32_nosext:
+; RV64IPN:       # %bb.0:
+; RV64IPN-NEXT:    srliw a2, a0, 8
+; RV64IPN-NEXT:    lui a3, 16
+; RV64IPN-NEXT:    addiw a3, a3, -256
+; RV64IPN-NEXT:    and a2, a2, a3
+; RV64IPN-NEXT:    srliw a3, a0, 24
+; RV64IPN-NEXT:    or a2, a2, a3
+; RV64IPN-NEXT:    slli a3, a0, 8
+; RV64IPN-NEXT:    lui a4, 4080
+; RV64IPN-NEXT:    and a3, a3, a4
+; RV64IPN-NEXT:    slli a0, a0, 24
+; RV64IPN-NEXT:    or a0, a0, a3
+; RV64IPN-NEXT:    or a0, a0, a2
+; RV64IPN-NEXT:    sw a0, 0(a1)
+; RV64IPN-NEXT:    ret
+;
+; RV64IBP-LABEL: bswap_i32_nosext:
+; RV64IBP:       # %bb.0:
+; RV64IBP-NEXT:    greviw a0, a0, 24
+; RV64IBP-NEXT:    sw a0, 0(a1)
+; RV64IBP-NEXT:    ret
+  %ret = tail call i32 @llvm.bswap.i32(i32 %a)
+  store i32 %ret, i32* %x
+  ret void
+}
+
+define i64 @bswap_i64(i64 %a) nounwind {
+; RV64IB-LABEL: bswap_i64:
+; RV64IB:       # %bb.0:
+; RV64IB-NEXT:    rev8 a0, a0
+; RV64IB-NEXT:    ret
+;
+; RV64IP-LABEL: bswap_i64:
+; RV64IP:       # %bb.0:
+; RV64IP-NEXT:    srli a1, a0, 24
+; RV64IP-NEXT:    lui a2, 4080
+; RV64IP-NEXT:    and a1, a1, a2
+; RV64IP-NEXT:    srli a2, a0, 8
+; RV64IP-NEXT:    addi a3, zero, 255
+; RV64IP-NEXT:    slli a4, a3, 24
+; RV64IP-NEXT:    and a2, a2, a4
+; RV64IP-NEXT:    or a1, a2, a1
+; RV64IP-NEXT:    srli a2, a0, 40
+; RV64IP-NEXT:    lui a4, 16
+; RV64IP-NEXT:    addiw a4, a4, -256
+; RV64IP-NEXT:    and a2, a2, a4
+; RV64IP-NEXT:    srli a4, a0, 56
+; RV64IP-NEXT:    or a2, a2, a4
+; RV64IP-NEXT:    or a1, a1, a2
+; RV64IP-NEXT:    slli a2, a0, 8
+; RV64IP-NEXT:    slli a4, a3, 32
+; RV64IP-NEXT:    and a2, a2, a4
+; RV64IP-NEXT:    slli a4, a0, 24
+; RV64IP-NEXT:    slli a5, a3, 40
+; RV64IP-NEXT:    and a4, a4, a5
+; RV64IP-NEXT:    or a2, a4, a2
+; RV64IP-NEXT:    slli a4, a0, 40
+; RV64IP-NEXT:    slli a3, a3, 48
+; RV64IP-NEXT:    and a3, a4, a3
+; RV64IP-NEXT:    slli a0, a0, 56
+; RV64IP-NEXT:    or a0, a0, a3
+; RV64IP-NEXT:    or a0, a0, a2
+; RV64IP-NEXT:    or a0, a0, a1
+; RV64IP-NEXT:    ret
+;
+; RV64IPN-LABEL: bswap_i64:
+; RV64IPN:       # %bb.0:
+; RV64IPN-NEXT:    srli a1, a0, 24
+; RV64IPN-NEXT:    lui a2, 4080
+; RV64IPN-NEXT:    and a1, a1, a2
+; RV64IPN-NEXT:    srli a2, a0, 8
+; RV64IPN-NEXT:    addi a3, zero, 255
+; RV64IPN-NEXT:    slli a4, a3, 24
+; RV64IPN-NEXT:    and a2, a2, a4
+; RV64IPN-NEXT:    or a1, a2, a1
+; RV64IPN-NEXT:    srli a2, a0, 40
+; RV64IPN-NEXT:    lui a4, 16
+; RV64IPN-NEXT:    addiw a4, a4, -256
+; RV64IPN-NEXT:    and a2, a2, a4
+; RV64IPN-NEXT:    srli a4, a0, 56
+; RV64IPN-NEXT:    or a2, a2, a4
+; RV64IPN-NEXT:    or a1, a1, a2
+; RV64IPN-NEXT:    slli a2, a0, 8
+; RV64IPN-NEXT:    slli a4, a3, 32
+; RV64IPN-NEXT:    and a2, a2, a4
+; RV64IPN-NEXT:    slli a4, a0, 24
+; RV64IPN-NEXT:    slli a5, a3, 40
+; RV64IPN-NEXT:    and a4, a4, a5
+; RV64IPN-NEXT:    or a2, a4, a2
+; RV64IPN-NEXT:    slli a4, a0, 40
+; RV64IPN-NEXT:    slli a3, a3, 48
+; RV64IPN-NEXT:    and a3, a4, a3
+; RV64IPN-NEXT:    slli a0, a0, 56
+; RV64IPN-NEXT:    or a0, a0, a3
+; RV64IPN-NEXT:    or a0, a0, a2
+; RV64IPN-NEXT:    or a0, a0, a1
+; RV64IPN-NEXT:    ret
+;
+; RV64IBP-LABEL: bswap_i64:
+; RV64IBP:       # %bb.0:
+; RV64IBP-NEXT:    rev8 a0, a0
+; RV64IBP-NEXT:    ret
+  %ret = tail call i64 @llvm.bswap.i64(i64 %a)
+  ret i64 %ret
+}