diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -9375,6 +9375,15 @@
   // fold (bswap (bswap x)) -> x
   if (N0.getOpcode() == ISD::BSWAP)
     return N0->getOperand(0);
+
+  // Canonicalize bswap(bitreverse(x)) -> bitreverse(bswap(x)). This helps
+  // when bitreverse gets expanded.
+  if (N0.getOpcode() == ISD::BITREVERSE && N0.hasOneUse()) {
+    SDLoc DL(N);
+    SDValue BSwap = DAG.getNode(ISD::BSWAP, DL, VT, N0.getOperand(0));
+    return DAG.getNode(ISD::BITREVERSE, DL, VT, BSwap);
+  }
+
   return SDValue();
 }
 
diff --git a/llvm/test/CodeGen/RISCV/bswap-bitreverse-ctlz-cttz-ctpop.ll b/llvm/test/CodeGen/RISCV/bswap-bitreverse-ctlz-cttz-ctpop.ll
--- a/llvm/test/CodeGen/RISCV/bswap-bitreverse-ctlz-cttz-ctpop.ll
+++ b/llvm/test/CodeGen/RISCV/bswap-bitreverse-ctlz-cttz-ctpop.ll
@@ -1039,10 +1039,6 @@
 define i16 @test_bitreverse_bswap_i16(i16 %a) nounwind {
 ; RV32I-LABEL: test_bitreverse_bswap_i16:
 ; RV32I:       # %bb.0:
-; RV32I-NEXT:    slli a1, a0, 8
-; RV32I-NEXT:    slli a0, a0, 16
-; RV32I-NEXT:    srli a0, a0, 24
-; RV32I-NEXT:    or a0, a1, a0
 ; RV32I-NEXT:    srli a1, a0, 4
 ; RV32I-NEXT:    lui a2, 1
 ; RV32I-NEXT:    addi a2, a2, -241
@@ -1064,17 +1060,10 @@
 ; RV32I-NEXT:    and a0, a0, a2
 ; RV32I-NEXT:    slli a0, a0, 1
 ; RV32I-NEXT:    or a0, a1, a0
-; RV32I-NEXT:    srli a1, a0, 8
-; RV32I-NEXT:    slli a0, a0, 8
-; RV32I-NEXT:    or a0, a0, a1
 ; RV32I-NEXT:    ret
 ;
 ; RV64I-LABEL: test_bitreverse_bswap_i16:
 ; RV64I:       # %bb.0:
-; RV64I-NEXT:    slli a1, a0, 8
-; RV64I-NEXT:    slli a0, a0, 48
-; RV64I-NEXT:    srli a0, a0, 56
-; RV64I-NEXT:    or a0, a1, a0
 ; RV64I-NEXT:    srli a1, a0, 4
 ; RV64I-NEXT:    lui a2, 1
 ; RV64I-NEXT:    addiw a2, a2, -241
@@ -1096,21 +1085,17 @@
 ; RV64I-NEXT:    and a0, a0, a2
 ; RV64I-NEXT:    slli a0, a0, 1
 ; RV64I-NEXT:    or a0, a1, a0
-; RV64I-NEXT:    srli a1, a0, 8
-; RV64I-NEXT:    slli a0, a0, 8
-; RV64I-NEXT:    or a0, a0, a1
 ; RV64I-NEXT:    ret
 ;
 ; RV32ZBB-LABEL: test_bitreverse_bswap_i16:
 ; RV32ZBB:       # %bb.0:
-; RV32ZBB-NEXT:    rev8 a0, a0
-; RV32ZBB-NEXT:    srli a1, a0, 12
-; RV32ZBB-NEXT:    lui a2, 15
-; RV32ZBB-NEXT:    addi a2, a2, 240
+; RV32ZBB-NEXT:    srli a1, a0, 4
+; RV32ZBB-NEXT:    lui a2, 1
+; RV32ZBB-NEXT:    addi a2, a2, -241
 ; RV32ZBB-NEXT:    and a1, a1, a2
-; RV32ZBB-NEXT:    srli a0, a0, 20
-; RV32ZBB-NEXT:    andi a0, a0, -241
-; RV32ZBB-NEXT:    or a0, a0, a1
+; RV32ZBB-NEXT:    and a0, a0, a2
+; RV32ZBB-NEXT:    slli a0, a0, 4
+; RV32ZBB-NEXT:    or a0, a1, a0
 ; RV32ZBB-NEXT:    srli a1, a0, 2
 ; RV32ZBB-NEXT:    lui a2, 3
 ; RV32ZBB-NEXT:    addi a2, a2, 819
@@ -1125,20 +1110,17 @@
 ; RV32ZBB-NEXT:    and a0, a0, a2
 ; RV32ZBB-NEXT:    slli a0, a0, 1
 ; RV32ZBB-NEXT:    or a0, a1, a0
-; RV32ZBB-NEXT:    rev8 a0, a0
-; RV32ZBB-NEXT:    srli a0, a0, 16
 ; RV32ZBB-NEXT:    ret
 ;
 ; RV64ZBB-LABEL: test_bitreverse_bswap_i16:
 ; RV64ZBB:       # %bb.0:
-; RV64ZBB-NEXT:    rev8 a0, a0
-; RV64ZBB-NEXT:    srli a1, a0, 44
-; RV64ZBB-NEXT:    lui a2, 15
-; RV64ZBB-NEXT:    addiw a2, a2, 240
+; RV64ZBB-NEXT:    srli a1, a0, 4
+; RV64ZBB-NEXT:    lui a2, 1
+; RV64ZBB-NEXT:    addiw a2, a2, -241
 ; RV64ZBB-NEXT:    and a1, a1, a2
-; RV64ZBB-NEXT:    srli a0, a0, 52
-; RV64ZBB-NEXT:    andi a0, a0, -241
-; RV64ZBB-NEXT:    or a0, a0, a1
+; RV64ZBB-NEXT:    and a0, a0, a2
+; RV64ZBB-NEXT:    slli a0, a0, 4
+; RV64ZBB-NEXT:    or a0, a1, a0
 ; RV64ZBB-NEXT:    srli a1, a0, 2
 ; RV64ZBB-NEXT:    lui a2, 3
 ; RV64ZBB-NEXT:    addiw a2, a2, 819
@@ -1153,8 +1135,6 @@
 ; RV64ZBB-NEXT:    and a0, a0, a2
 ; RV64ZBB-NEXT:    slli a0, a0, 1
 ; RV64ZBB-NEXT:    or a0, a1, a0
-; RV64ZBB-NEXT:    rev8 a0, a0
-; RV64ZBB-NEXT:    srli a0, a0, 48
 ; RV64ZBB-NEXT:    ret
   %tmp = call i16 @llvm.bitreverse.i16(i16 %a)
   %tmp2 = call i16 @llvm.bswap.i16(i16 %tmp)
@@ -1164,99 +1144,56 @@
 define i32 @test_bitreverse_bswap_i32(i32 %a) nounwind {
 ; RV32I-LABEL: test_bitreverse_bswap_i32:
 ; RV32I:       # %bb.0:
-; RV32I-NEXT:    srli a1, a0, 8
-; RV32I-NEXT:    lui a2, 16
-; RV32I-NEXT:    addi a2, a2, -256
-; RV32I-NEXT:    and a1, a1, a2
-; RV32I-NEXT:    srli a3, a0, 24
-; RV32I-NEXT:    or a1, a1, a3
-; RV32I-NEXT:    slli a3, a0, 8
-; RV32I-NEXT:    lui a4, 4080
-; RV32I-NEXT:    and a3, a3, a4
-; RV32I-NEXT:    slli a0, a0, 24
-; RV32I-NEXT:    or a0, a0, a3
-; RV32I-NEXT:    or a0, a0, a1
 ; RV32I-NEXT:    srli a1, a0, 4
-; RV32I-NEXT:    lui a3, 61681
-; RV32I-NEXT:    addi a3, a3, -241
-; RV32I-NEXT:    and a1, a1, a3
-; RV32I-NEXT:    and a0, a0, a3
+; RV32I-NEXT:    lui a2, 61681
+; RV32I-NEXT:    addi a2, a2, -241
+; RV32I-NEXT:    and a1, a1, a2
+; RV32I-NEXT:    and a0, a0, a2
 ; RV32I-NEXT:    slli a0, a0, 4
 ; RV32I-NEXT:    or a0, a1, a0
 ; RV32I-NEXT:    srli a1, a0, 2
-; RV32I-NEXT:    lui a3, 209715
-; RV32I-NEXT:    addi a3, a3, 819
-; RV32I-NEXT:    and a1, a1, a3
-; RV32I-NEXT:    and a0, a0, a3
+; RV32I-NEXT:    lui a2, 209715
+; RV32I-NEXT:    addi a2, a2, 819
+; RV32I-NEXT:    and a1, a1, a2
+; RV32I-NEXT:    and a0, a0, a2
 ; RV32I-NEXT:    slli a0, a0, 2
 ; RV32I-NEXT:    or a0, a1, a0
 ; RV32I-NEXT:    srli a1, a0, 1
-; RV32I-NEXT:    lui a3, 349525
-; RV32I-NEXT:    addi a3, a3, 1365
-; RV32I-NEXT:    and a1, a1, a3
-; RV32I-NEXT:    and a0, a0, a3
+; RV32I-NEXT:    lui a2, 349525
+; RV32I-NEXT:    addi a2, a2, 1365
+; RV32I-NEXT:    and a1, a1, a2
+; RV32I-NEXT:    and a0, a0, a2
 ; RV32I-NEXT:    slli a0, a0, 1
 ; RV32I-NEXT:    or a0, a1, a0
-; RV32I-NEXT:    srli a1, a0, 8
-; RV32I-NEXT:    and a1, a1, a2
-; RV32I-NEXT:    srli a2, a0, 24
-; RV32I-NEXT:    or a1, a1, a2
-; RV32I-NEXT:    slli a2, a0, 8
-; RV32I-NEXT:    and a2, a2, a4
-; RV32I-NEXT:    slli a0, a0, 24
-; RV32I-NEXT:    or a0, a0, a2
-; RV32I-NEXT:    or a0, a0, a1
 ; RV32I-NEXT:    ret
 ;
 ; RV64I-LABEL: test_bitreverse_bswap_i32:
 ; RV64I:       # %bb.0:
-; RV64I-NEXT:    srliw a1, a0, 8
-; RV64I-NEXT:    lui a2, 16
-; RV64I-NEXT:    addiw a2, a2, -256
-; RV64I-NEXT:    and a1, a1, a2
-; RV64I-NEXT:    srliw a3, a0, 24
-; RV64I-NEXT:    or a1, a1, a3
-; RV64I-NEXT:    slli a3, a0, 8
-; RV64I-NEXT:    lui a4, 4080
-; RV64I-NEXT:    and a3, a3, a4
-; RV64I-NEXT:    slliw a0, a0, 24
-; RV64I-NEXT:    or a0, a0, a3
-; RV64I-NEXT:    or a0, a0, a1
 ; RV64I-NEXT:    srli a1, a0, 4
-; RV64I-NEXT:    lui a3, 61681
-; RV64I-NEXT:    addiw a3, a3, -241
-; RV64I-NEXT:    and a1, a1, a3
-; RV64I-NEXT:    and a0, a0, a3
+; RV64I-NEXT:    lui a2, 61681
+; RV64I-NEXT:    addiw a2, a2, -241
+; RV64I-NEXT:    and a1, a1, a2
+; RV64I-NEXT:    and a0, a0, a2
 ; RV64I-NEXT:    slliw a0, a0, 4
 ; RV64I-NEXT:    or a0, a1, a0
 ; RV64I-NEXT:    srli a1, a0, 2
-; RV64I-NEXT:    lui a3, 209715
-; RV64I-NEXT:    addiw a3, a3, 819
-; RV64I-NEXT:    and a1, a1, a3
-; RV64I-NEXT:    and a0, a0, a3
+; RV64I-NEXT:    lui a2, 209715
+; RV64I-NEXT:    addiw a2, a2, 819
+; RV64I-NEXT:    and a1, a1, a2
+; RV64I-NEXT:    and a0, a0, a2
 ; RV64I-NEXT:    slliw a0, a0, 2
 ; RV64I-NEXT:    or a0, a1, a0
 ; RV64I-NEXT:    srli a1, a0, 1
-; RV64I-NEXT:    lui a3, 349525
-; RV64I-NEXT:    addiw a3, a3, 1365
-; RV64I-NEXT:    and a1, a1, a3
-; RV64I-NEXT:    and a0, a0, a3
+; RV64I-NEXT:    lui a2, 349525
+; RV64I-NEXT:    addiw a2, a2, 1365
+; RV64I-NEXT:    and a1, a1, a2
+; RV64I-NEXT:    and a0, a0, a2
 ; RV64I-NEXT:    slliw a0, a0, 1
 ; RV64I-NEXT:    or a0, a1, a0
-; RV64I-NEXT:    srliw a1, a0, 8
-; RV64I-NEXT:    and a1, a1, a2
-; RV64I-NEXT:    srliw a2, a0, 24
-; RV64I-NEXT:    or a1, a1, a2
-; RV64I-NEXT:    slli a2, a0, 8
-; RV64I-NEXT:    and a2, a2, a4
-; RV64I-NEXT:    slliw a0, a0, 24
-; RV64I-NEXT:    or a0, a0, a2
-; RV64I-NEXT:    or a0, a0, a1
 ; RV64I-NEXT:    ret
 ;
 ; RV32ZBB-LABEL: test_bitreverse_bswap_i32:
 ; RV32ZBB:       # %bb.0:
-; RV32ZBB-NEXT:    rev8 a0, a0
 ; RV32ZBB-NEXT:    srli a1, a0, 4
 ; RV32ZBB-NEXT:    lui a2, 61681
 ; RV32ZBB-NEXT:    addi a2, a2, -241
@@ -1278,21 +1215,16 @@
 ; RV32ZBB-NEXT:    and a0, a0, a2
 ; RV32ZBB-NEXT:    slli a0, a0, 1
 ; RV32ZBB-NEXT:    or a0, a1, a0
-; RV32ZBB-NEXT:    rev8 a0, a0
 ; RV32ZBB-NEXT:    ret
 ;
 ; RV64ZBB-LABEL: test_bitreverse_bswap_i32:
 ; RV64ZBB:       # %bb.0:
-; RV64ZBB-NEXT:    rev8 a0, a0
-; RV64ZBB-NEXT:    srli a1, a0, 36
+; RV64ZBB-NEXT:    srli a1, a0, 4
 ; RV64ZBB-NEXT:    lui a2, 61681
 ; RV64ZBB-NEXT:    addiw a2, a2, -241
 ; RV64ZBB-NEXT:    and a1, a1, a2
-; RV64ZBB-NEXT:    srli a0, a0, 28
-; RV64ZBB-NEXT:    lui a2, 986895
-; RV64ZBB-NEXT:    addiw a2, a2, 240
 ; RV64ZBB-NEXT:    and a0, a0, a2
-; RV64ZBB-NEXT:    sext.w a0, a0
+; RV64ZBB-NEXT:    slliw a0, a0, 4
 ; RV64ZBB-NEXT:    or a0, a1, a0
 ; RV64ZBB-NEXT:    srli a1, a0, 2
 ; RV64ZBB-NEXT:    lui a2, 209715
@@ -1306,10 +1238,8 @@
 ; RV64ZBB-NEXT:    addiw a2, a2, 1365
 ; RV64ZBB-NEXT:    and a1, a1, a2
 ; RV64ZBB-NEXT:    and a0, a0, a2
-; RV64ZBB-NEXT:    slli a0, a0, 1
+; RV64ZBB-NEXT:    slliw a0, a0, 1
 ; RV64ZBB-NEXT:    or a0, a1, a0
-; RV64ZBB-NEXT:    rev8 a0, a0
-; RV64ZBB-NEXT:    srli a0, a0, 32
 ; RV64ZBB-NEXT:    ret
   %tmp = call i32 @llvm.bitreverse.i32(i32 %a)
   %tmp2 = call i32 @llvm.bswap.i32(i32 %tmp)
@@ -1319,206 +1249,113 @@
 define i64 @test_bitreverse_bswap_i64(i64 %a) nounwind {
 ; RV32I-LABEL: test_bitreverse_bswap_i64:
 ; RV32I:       # %bb.0:
-; RV32I-NEXT:    srli a3, a1, 8
-; RV32I-NEXT:    lui a2, 16
-; RV32I-NEXT:    addi a2, a2, -256
-; RV32I-NEXT:    and a3, a3, a2
-; RV32I-NEXT:    srli a4, a1, 24
-; RV32I-NEXT:    or a4, a3, a4
-; RV32I-NEXT:    slli a5, a1, 8
-; RV32I-NEXT:    lui a3, 4080
-; RV32I-NEXT:    and a5, a5, a3
-; RV32I-NEXT:    slli a1, a1, 24
-; RV32I-NEXT:    or a1, a1, a5
-; RV32I-NEXT:    or a1, a1, a4
-; RV32I-NEXT:    srli a4, a1, 4
-; RV32I-NEXT:    lui a5, 61681
-; RV32I-NEXT:    addi a5, a5, -241
-; RV32I-NEXT:    and a4, a4, a5
-; RV32I-NEXT:    and a1, a1, a5
-; RV32I-NEXT:    slli a1, a1, 4
-; RV32I-NEXT:    or a1, a4, a1
-; RV32I-NEXT:    srli a4, a1, 2
-; RV32I-NEXT:    lui a6, 209715
-; RV32I-NEXT:    addi a6, a6, 819
-; RV32I-NEXT:    and a4, a4, a6
-; RV32I-NEXT:    and a1, a1, a6
-; RV32I-NEXT:    slli a1, a1, 2
-; RV32I-NEXT:    or a1, a4, a1
-; RV32I-NEXT:    srli a4, a1, 1
-; RV32I-NEXT:    lui a7, 349525
-; RV32I-NEXT:    addi a7, a7, 1365
-; RV32I-NEXT:    and a4, a4, a7
-; RV32I-NEXT:    and a1, a1, a7
-; RV32I-NEXT:    slli a1, a1, 1
-; RV32I-NEXT:    or a1, a4, a1
-; RV32I-NEXT:    srli a4, a0, 8
-; RV32I-NEXT:    and a4, a4, a2
-; RV32I-NEXT:    srli t0, a0, 24
-; RV32I-NEXT:    or a4, a4, t0
-; RV32I-NEXT:    slli t0, a0, 8
-; RV32I-NEXT:    and t0, t0, a3
-; RV32I-NEXT:    slli a0, a0, 24
-; RV32I-NEXT:    or a0, a0, t0
-; RV32I-NEXT:    or a0, a0, a4
-; RV32I-NEXT:    srli a4, a0, 4
-; RV32I-NEXT:    and a4, a4, a5
-; RV32I-NEXT:    and a0, a0, a5
+; RV32I-NEXT:    srli a2, a0, 4
+; RV32I-NEXT:    lui a3, 61681
+; RV32I-NEXT:    addi a3, a3, -241
+; RV32I-NEXT:    and a2, a2, a3
+; RV32I-NEXT:    and a0, a0, a3
 ; RV32I-NEXT:    slli a0, a0, 4
-; RV32I-NEXT:    or a0, a4, a0
-; RV32I-NEXT:    srli a4, a0, 2
-; RV32I-NEXT:    and a4, a4, a6
-; RV32I-NEXT:    and a0, a0, a6
+; RV32I-NEXT:    or a0, a2, a0
+; RV32I-NEXT:    srli a2, a0, 2
+; RV32I-NEXT:    lui a4, 209715
+; RV32I-NEXT:    addi a4, a4, 819
+; RV32I-NEXT:    and a2, a2, a4
+; RV32I-NEXT:    and a0, a0, a4
 ; RV32I-NEXT:    slli a0, a0, 2
-; RV32I-NEXT:    or a0, a4, a0
-; RV32I-NEXT:    srli a4, a0, 1
-; RV32I-NEXT:    and a4, a4, a7
-; RV32I-NEXT:    and a0, a0, a7
+; RV32I-NEXT:    or a0, a2, a0
+; RV32I-NEXT:    srli a2, a0, 1
+; RV32I-NEXT:    lui a5, 349525
+; RV32I-NEXT:    addi a5, a5, 1365
+; RV32I-NEXT:    and a2, a2, a5
+; RV32I-NEXT:    and a0, a0, a5
 ; RV32I-NEXT:    slli a0, a0, 1
-; RV32I-NEXT:    or a0, a4, a0
-; RV32I-NEXT:    srli a4, a0, 8
-; RV32I-NEXT:    and a4, a4, a2
-; RV32I-NEXT:    srli a5, a0, 24
-; RV32I-NEXT:    or a4, a4, a5
-; RV32I-NEXT:    slli a5, a0, 8
-; RV32I-NEXT:    and a5, a5, a3
-; RV32I-NEXT:    slli a0, a0, 24
-; RV32I-NEXT:    or a0, a0, a5
-; RV32I-NEXT:    or a0, a0, a4
-; RV32I-NEXT:    srli a4, a1, 8
-; RV32I-NEXT:    and a2, a4, a2
-; RV32I-NEXT:    srli a4, a1, 24
-; RV32I-NEXT:    or a2, a2, a4
-; RV32I-NEXT:    slli a4, a1, 8
-; RV32I-NEXT:    and a3, a4, a3
-; RV32I-NEXT:    slli a1, a1, 24
-; RV32I-NEXT:    or a1, a1, a3
-; RV32I-NEXT:    or a1, a1, a2
+; RV32I-NEXT:    or a0, a2, a0
+; RV32I-NEXT:    srli a2, a1, 4
+; RV32I-NEXT:    and a2, a2, a3
+; RV32I-NEXT:    and a1, a1, a3
+; RV32I-NEXT:    slli a1, a1, 4
+; RV32I-NEXT:    or a1, a2, a1
+; RV32I-NEXT:    srli a2, a1, 2
+; RV32I-NEXT:    and a2, a2, a4
+; RV32I-NEXT:    and a1, a1, a4
+; RV32I-NEXT:    slli a1, a1, 2
+; RV32I-NEXT:    or a1, a2, a1
+; RV32I-NEXT:    srli a2, a1, 1
+; RV32I-NEXT:    and a2, a2, a5
+; RV32I-NEXT:    and a1, a1, a5
+; RV32I-NEXT:    slli a1, a1, 1
+; RV32I-NEXT:    or a1, a2, a1
 ; RV32I-NEXT:    ret
 ;
 ; RV64I-LABEL: test_bitreverse_bswap_i64:
 ; RV64I:       # %bb.0:
-; RV64I-NEXT:    srli a1, a0, 24
-; RV64I-NEXT:    lui a2, 4080
-; RV64I-NEXT:    and a1, a1, a2
-; RV64I-NEXT:    srli a3, a0, 8
-; RV64I-NEXT:    li a4, 255
-; RV64I-NEXT:    slli a5, a4, 24
-; RV64I-NEXT:    and a3, a3, a5
-; RV64I-NEXT:    or a1, a3, a1
-; RV64I-NEXT:    srli a3, a0, 40
-; RV64I-NEXT:    lui a6, 16
-; RV64I-NEXT:    addiw a6, a6, -256
-; RV64I-NEXT:    and a3, a3, a6
-; RV64I-NEXT:    srli a7, a0, 56
-; RV64I-NEXT:    or a3, a3, a7
-; RV64I-NEXT:    or a1, a1, a3
-; RV64I-NEXT:    slli a3, a0, 24
-; RV64I-NEXT:    slli a7, a4, 40
-; RV64I-NEXT:    and a3, a3, a7
-; RV64I-NEXT:    srliw t0, a0, 24
-; RV64I-NEXT:    slli t0, t0, 32
-; RV64I-NEXT:    or a3, a3, t0
-; RV64I-NEXT:    slli t0, a0, 40
-; RV64I-NEXT:    slli a4, a4, 48
-; RV64I-NEXT:    and t0, t0, a4
-; RV64I-NEXT:    slli a0, a0, 56
-; RV64I-NEXT:    or a0, a0, t0
-; RV64I-NEXT:    lui t0, %hi(.LCPI12_0)
-; RV64I-NEXT:    ld t0, %lo(.LCPI12_0)(t0)
-; RV64I-NEXT:    or a0, a0, a3
-; RV64I-NEXT:    or a0, a0, a1
-; RV64I-NEXT:    srli a1, a0, 4
-; RV64I-NEXT:    and a1, a1, t0
-; RV64I-NEXT:    and a0, a0, t0
-; RV64I-NEXT:    lui a3, %hi(.LCPI12_1)
-; RV64I-NEXT:    ld a3, %lo(.LCPI12_1)(a3)
+; RV64I-NEXT:    lui a1, %hi(.LCPI12_0)
+; RV64I-NEXT:    ld a1, %lo(.LCPI12_0)(a1)
+; RV64I-NEXT:    srli a2, a0, 4
+; RV64I-NEXT:    and a2, a2, a1
+; RV64I-NEXT:    and a0, a0, a1
+; RV64I-NEXT:    lui a1, %hi(.LCPI12_1)
+; RV64I-NEXT:    ld a1, %lo(.LCPI12_1)(a1)
 ; RV64I-NEXT:    slli a0, a0, 4
-; RV64I-NEXT:    or a0, a1, a0
-; RV64I-NEXT:    srli a1, a0, 2
-; RV64I-NEXT:    and a1, a1, a3
-; RV64I-NEXT:    and a0, a0, a3
-; RV64I-NEXT:    lui a3, %hi(.LCPI12_2)
-; RV64I-NEXT:    ld a3, %lo(.LCPI12_2)(a3)
+; RV64I-NEXT:    or a0, a2, a0
+; RV64I-NEXT:    srli a2, a0, 2
+; RV64I-NEXT:    and a2, a2, a1
+; RV64I-NEXT:    and a0, a0, a1
+; RV64I-NEXT:    lui a1, %hi(.LCPI12_2)
+; RV64I-NEXT:    ld a1, %lo(.LCPI12_2)(a1)
 ; RV64I-NEXT:    slli a0, a0, 2
-; RV64I-NEXT:    or a0, a1, a0
-; RV64I-NEXT:    srli a1, a0, 1
-; RV64I-NEXT:    and a1, a1, a3
-; RV64I-NEXT:    and a0, a0, a3
+; RV64I-NEXT:    or a0, a2, a0
+; RV64I-NEXT:    srli a2, a0, 1
+; RV64I-NEXT:    and a2, a2, a1
+; RV64I-NEXT:    and a0, a0, a1
 ; RV64I-NEXT:    slli a0, a0, 1
-; RV64I-NEXT:    or a0, a1, a0
-; RV64I-NEXT:    srli a1, a0, 40
-; RV64I-NEXT:    and a1, a1, a6
-; RV64I-NEXT:    srli a3, a0, 56
-; RV64I-NEXT:    or a1, a1, a3
-; RV64I-NEXT:    srli a3, a0, 24
-; RV64I-NEXT:    and a2, a3, a2
-; RV64I-NEXT:    srli a3, a0, 8
-; RV64I-NEXT:    and a3, a3, a5
-; RV64I-NEXT:    or a2, a3, a2
-; RV64I-NEXT:    or a1, a2, a1
-; RV64I-NEXT:    slli a2, a0, 24
-; RV64I-NEXT:    and a2, a2, a7
-; RV64I-NEXT:    srliw a3, a0, 24
-; RV64I-NEXT:    slli a3, a3, 32
-; RV64I-NEXT:    or a2, a2, a3
-; RV64I-NEXT:    slli a3, a0, 40
-; RV64I-NEXT:    and a3, a3, a4
-; RV64I-NEXT:    slli a0, a0, 56
-; RV64I-NEXT:    or a0, a0, a3
-; RV64I-NEXT:    or a0, a0, a2
-; RV64I-NEXT:    or a0, a0, a1
+; RV64I-NEXT:    or a0, a2, a0
 ; RV64I-NEXT:    ret
 ;
 ; RV32ZBB-LABEL: test_bitreverse_bswap_i64:
 ; RV32ZBB:       # %bb.0:
-; RV32ZBB-NEXT:    rev8 a1, a1
-; RV32ZBB-NEXT:    srli a2, a1, 4
+; RV32ZBB-NEXT:    srli a2, a0, 4
 ; RV32ZBB-NEXT:    lui a3, 61681
 ; RV32ZBB-NEXT:    addi a3, a3, -241
 ; RV32ZBB-NEXT:    and a2, a2, a3
-; RV32ZBB-NEXT:    and a1, a1, a3
-; RV32ZBB-NEXT:    slli a1, a1, 4
-; RV32ZBB-NEXT:    or a1, a2, a1
-; RV32ZBB-NEXT:    srli a2, a1, 2
-; RV32ZBB-NEXT:    lui a4, 209715
-; RV32ZBB-NEXT:    addi a4, a4, 819
-; RV32ZBB-NEXT:    and a2, a2, a4
-; RV32ZBB-NEXT:    and a1, a1, a4
-; RV32ZBB-NEXT:    slli a1, a1, 2
-; RV32ZBB-NEXT:    or a1, a2, a1
-; RV32ZBB-NEXT:    srli a2, a1, 1
-; RV32ZBB-NEXT:    lui a5, 349525
-; RV32ZBB-NEXT:    addi a5, a5, 1365
-; RV32ZBB-NEXT:    and a2, a2, a5
-; RV32ZBB-NEXT:    and a1, a1, a5
-; RV32ZBB-NEXT:    slli a1, a1, 1
-; RV32ZBB-NEXT:    or a1, a2, a1
-; RV32ZBB-NEXT:    rev8 a0, a0
-; RV32ZBB-NEXT:    srli a2, a0, 4
-; RV32ZBB-NEXT:    and a2, a2, a3
 ; RV32ZBB-NEXT:    and a0, a0, a3
 ; RV32ZBB-NEXT:    slli a0, a0, 4
 ; RV32ZBB-NEXT:    or a0, a2, a0
 ; RV32ZBB-NEXT:    srli a2, a0, 2
+; RV32ZBB-NEXT:    lui a4, 209715
+; RV32ZBB-NEXT:    addi a4, a4, 819
 ; RV32ZBB-NEXT:    and a2, a2, a4
 ; RV32ZBB-NEXT:    and a0, a0, a4
 ; RV32ZBB-NEXT:    slli a0, a0, 2
 ; RV32ZBB-NEXT:    or a0, a2, a0
 ; RV32ZBB-NEXT:    srli a2, a0, 1
+; RV32ZBB-NEXT:    lui a5, 349525
+; RV32ZBB-NEXT:    addi a5, a5, 1365
 ; RV32ZBB-NEXT:    and a2, a2, a5
 ; RV32ZBB-NEXT:    and a0, a0, a5
 ; RV32ZBB-NEXT:    slli a0, a0, 1
 ; RV32ZBB-NEXT:    or a0, a2, a0
-; RV32ZBB-NEXT:    rev8 a0, a0
-; RV32ZBB-NEXT:    rev8 a1, a1
+; RV32ZBB-NEXT:    srli a2, a1, 4
+; RV32ZBB-NEXT:    and a2, a2, a3
+; RV32ZBB-NEXT:    and a1, a1, a3
+; RV32ZBB-NEXT:    slli a1, a1, 4
+; RV32ZBB-NEXT:    or a1, a2, a1
+; RV32ZBB-NEXT:    srli a2, a1, 2
+; RV32ZBB-NEXT:    and a2, a2, a4
+; RV32ZBB-NEXT:    and a1, a1, a4
+; RV32ZBB-NEXT:    slli a1, a1, 2
+; RV32ZBB-NEXT:    or a1, a2, a1
+; RV32ZBB-NEXT:    srli a2, a1, 1
+; RV32ZBB-NEXT:    and a2, a2, a5
+; RV32ZBB-NEXT:    and a1, a1, a5
+; RV32ZBB-NEXT:    slli a1, a1, 1
+; RV32ZBB-NEXT:    or a1, a2, a1
 ; RV32ZBB-NEXT:    ret
 ;
 ; RV64ZBB-LABEL: test_bitreverse_bswap_i64:
 ; RV64ZBB:       # %bb.0:
 ; RV64ZBB-NEXT:    lui a1, %hi(.LCPI12_0)
 ; RV64ZBB-NEXT:    ld a1, %lo(.LCPI12_0)(a1)
-; RV64ZBB-NEXT:    rev8 a0, a0
 ; RV64ZBB-NEXT:    srli a2, a0, 4
 ; RV64ZBB-NEXT:    and a2, a2, a1
 ; RV64ZBB-NEXT:    and a0, a0, a1
@@ -1538,7 +1375,6 @@
 ; RV64ZBB-NEXT:    and a0, a0, a1
 ; RV64ZBB-NEXT:    slli a0, a0, 1
 ; RV64ZBB-NEXT:    or a0, a2, a0
-; RV64ZBB-NEXT:    rev8 a0, a0
 ; RV64ZBB-NEXT:    ret
   %tmp = call i64 @llvm.bitreverse.i64(i64 %a)
   %tmp2 = call i64 @llvm.bswap.i64(i64 %tmp)
diff --git a/llvm/test/CodeGen/RISCV/rv32zbp.ll b/llvm/test/CodeGen/RISCV/rv32zbp.ll
--- a/llvm/test/CodeGen/RISCV/rv32zbp.ll
+++ b/llvm/test/CodeGen/RISCV/rv32zbp.ll
@@ -2404,48 +2404,27 @@
 define i32 @bitreverse_bswap_i32(i32 %a) {
 ; RV32I-LABEL: bitreverse_bswap_i32:
 ; RV32I:       # %bb.0:
-; RV32I-NEXT:    srli a1, a0, 8
-; RV32I-NEXT:    lui a2, 16
-; RV32I-NEXT:    addi a2, a2, -256
-; RV32I-NEXT:    and a1, a1, a2
-; RV32I-NEXT:    srli a3, a0, 24
-; RV32I-NEXT:    or a1, a1, a3
-; RV32I-NEXT:    slli a3, a0, 8
-; RV32I-NEXT:    lui a4, 4080
-; RV32I-NEXT:    and a3, a3, a4
-; RV32I-NEXT:    slli a0, a0, 24
-; RV32I-NEXT:    or a0, a0, a3
-; RV32I-NEXT:    or a0, a0, a1
 ; RV32I-NEXT:    srli a1, a0, 4
-; RV32I-NEXT:    lui a3, 61681
-; RV32I-NEXT:    addi a3, a3, -241
-; RV32I-NEXT:    and a1, a1, a3
-; RV32I-NEXT:    and a0, a0, a3
+; RV32I-NEXT:    lui a2, 61681
+; RV32I-NEXT:    addi a2, a2, -241
+; RV32I-NEXT:    and a1, a1, a2
+; RV32I-NEXT:    and a0, a0, a2
 ; RV32I-NEXT:    slli a0, a0, 4
 ; RV32I-NEXT:    or a0, a1, a0
 ; RV32I-NEXT:    srli a1, a0, 2
-; RV32I-NEXT:    lui a3, 209715
-; RV32I-NEXT:    addi a3, a3, 819
-; RV32I-NEXT:    and a1, a1, a3
-; RV32I-NEXT:    and a0, a0, a3
+; RV32I-NEXT:    lui a2, 209715
+; RV32I-NEXT:    addi a2, a2, 819
+; RV32I-NEXT:    and a1, a1, a2
+; RV32I-NEXT:    and a0, a0, a2
 ; RV32I-NEXT:    slli a0, a0, 2
 ; RV32I-NEXT:    or a0, a1, a0
 ; RV32I-NEXT:    srli a1, a0, 1
-; RV32I-NEXT:    lui a3, 349525
-; RV32I-NEXT:    addi a3, a3, 1365
-; RV32I-NEXT:    and a1, a1, a3
-; RV32I-NEXT:    and a0, a0, a3
+; RV32I-NEXT:    lui a2, 349525
+; RV32I-NEXT:    addi a2, a2, 1365
+; RV32I-NEXT:    and a1, a1, a2
+; RV32I-NEXT:    and a0, a0, a2
 ; RV32I-NEXT:    slli a0, a0, 1
 ; RV32I-NEXT:    or a0, a1, a0
-; RV32I-NEXT:    srli a1, a0, 8
-; RV32I-NEXT:    and a1, a1, a2
-; RV32I-NEXT:    srli a2, a0, 24
-; RV32I-NEXT:    or a1, a1, a2
-; RV32I-NEXT:    slli a2, a0, 8
-; RV32I-NEXT:    and a2, a2, a4
-; RV32I-NEXT:    slli a0, a0, 24
-; RV32I-NEXT:    or a0, a0, a2
-; RV32I-NEXT:    or a0, a0, a1
 ; RV32I-NEXT:    ret
 ;
 ; RV32ZBP-LABEL: bitreverse_bswap_i32:
@@ -2460,81 +2439,42 @@
 define i64 @bitreverse_bswap_i64(i64 %a) {
 ; RV32I-LABEL: bitreverse_bswap_i64:
 ; RV32I:       # %bb.0:
-; RV32I-NEXT:    srli a3, a1, 8
-; RV32I-NEXT:    lui a2, 16
-; RV32I-NEXT:    addi a2, a2, -256
-; RV32I-NEXT:    and a3, a3, a2
-; RV32I-NEXT:    srli a4, a1, 24
-; RV32I-NEXT:    or a4, a3, a4
-; RV32I-NEXT:    slli a5, a1, 8
-; RV32I-NEXT:    lui a3, 4080
-; RV32I-NEXT:    and a5, a5, a3
-; RV32I-NEXT:    slli a1, a1, 24
-; RV32I-NEXT:    or a1, a1, a5
-; RV32I-NEXT:    or a1, a1, a4
-; RV32I-NEXT:    srli a4, a1, 4
-; RV32I-NEXT:    lui a5, 61681
-; RV32I-NEXT:    addi a5, a5, -241
-; RV32I-NEXT:    and a4, a4, a5
-; RV32I-NEXT:    and a1, a1, a5
-; RV32I-NEXT:    slli a1, a1, 4
-; RV32I-NEXT:    or a1, a4, a1
-; RV32I-NEXT:    srli a4, a1, 2
-; RV32I-NEXT:    lui a6, 209715
-; RV32I-NEXT:    addi a6, a6, 819
-; RV32I-NEXT:    and a4, a4, a6
-; RV32I-NEXT:    and a1, a1, a6
-; RV32I-NEXT:    slli a1, a1, 2
-; RV32I-NEXT:    or a1, a4, a1
-; RV32I-NEXT:    srli a4, a1, 1
-; RV32I-NEXT:    lui a7, 349525
-; RV32I-NEXT:    addi a7, a7, 1365
-; RV32I-NEXT:    and a4, a4, a7
-; RV32I-NEXT:    and a1, a1, a7
-; RV32I-NEXT:    slli a1, a1, 1
-; RV32I-NEXT:    or a1, a4, a1
-; RV32I-NEXT:    srli a4, a0, 8
-; RV32I-NEXT:    and a4, a4, a2
-; RV32I-NEXT:    srli t0, a0, 24
-; RV32I-NEXT:    or a4, a4, t0
-; RV32I-NEXT:    slli t0, a0, 8
-; RV32I-NEXT:    and t0, t0, a3
-; RV32I-NEXT:    slli a0, a0, 24
-; RV32I-NEXT:    or a0, a0, t0
-; RV32I-NEXT:    or a0, a0, a4
-; RV32I-NEXT:    srli a4, a0, 4
-; RV32I-NEXT:    and a4, a4, a5
-; RV32I-NEXT:    and a0, a0, a5
+; RV32I-NEXT:    srli a2, a0, 4
+; RV32I-NEXT:    lui a3, 61681
+; RV32I-NEXT:    addi a3, a3, -241
+; RV32I-NEXT:    and a2, a2, a3
+; RV32I-NEXT:    and a0, a0, a3
 ; RV32I-NEXT:    slli a0, a0, 4
-; RV32I-NEXT:    or a0, a4, a0
-; RV32I-NEXT:    srli a4, a0, 2
-; RV32I-NEXT:    and a4, a4, a6
-; RV32I-NEXT:    and a0, a0, a6
+; RV32I-NEXT:    or a0, a2, a0
+; RV32I-NEXT:    srli a2, a0, 2
+; RV32I-NEXT:    lui a4, 209715
+; RV32I-NEXT:    addi a4, a4, 819
+; RV32I-NEXT:    and a2, a2, a4
+; RV32I-NEXT:    and a0, a0, a4
 ; RV32I-NEXT:    slli a0, a0, 2
-; RV32I-NEXT:    or a0, a4, a0
-; RV32I-NEXT:    srli a4, a0, 1
-; RV32I-NEXT:    and a4, a4, a7
-; RV32I-NEXT:    and a0, a0, a7
+; RV32I-NEXT:    or a0, a2, a0
+; RV32I-NEXT:    srli a2, a0, 1
+; RV32I-NEXT:    lui a5, 349525
+; RV32I-NEXT:    addi a5, a5, 1365
+; RV32I-NEXT:    and a2, a2, a5
+; RV32I-NEXT:    and a0, a0, a5
 ; RV32I-NEXT:    slli a0, a0, 1
-; RV32I-NEXT:    or a0, a4, a0
-; RV32I-NEXT:    srli a4, a0, 8
-; RV32I-NEXT:    and a4, a4, a2
-; RV32I-NEXT:    srli a5, a0, 24
-; RV32I-NEXT:    or a4, a4, a5
-; RV32I-NEXT:    slli a5, a0, 8
-; RV32I-NEXT:    and a5, a5, a3
-; RV32I-NEXT:    slli a0, a0, 24
-; RV32I-NEXT:    or a0, a0, a5
-; RV32I-NEXT:    or a0, a0, a4
-; RV32I-NEXT:    srli a4, a1, 8
-; RV32I-NEXT:    and a2, a4, a2
-; RV32I-NEXT:    srli a4, a1, 24
-; RV32I-NEXT:    or a2, a2, a4
-; RV32I-NEXT:    slli a4, a1, 8
-; RV32I-NEXT:    and a3, a4, a3
-; RV32I-NEXT:    slli a1, a1, 24
-; RV32I-NEXT:    or a1, a1, a3
-; RV32I-NEXT:    or a1, a1, a2
+; RV32I-NEXT:    or a0, a2, a0
+; RV32I-NEXT:    srli a2, a1, 4
+; RV32I-NEXT:    and a2, a2, a3
+; RV32I-NEXT:    and a1, a1, a3
+; RV32I-NEXT:    slli a1, a1, 4
+; RV32I-NEXT:    or a1, a2, a1
+; RV32I-NEXT:    srli a2, a1, 2
+; RV32I-NEXT:    and a2, a2, a4
+; RV32I-NEXT:    and a1, a1, a4
+; RV32I-NEXT:    slli a1, a1, 2
+; RV32I-NEXT:    or a1, a2, a1
+; RV32I-NEXT:    srli a2, a1, 1
+; RV32I-NEXT:    and a2, a2, a5
+; RV32I-NEXT:    and a1, a1, a5
+; RV32I-NEXT:    slli a1, a1, 1
+; RV32I-NEXT:    or a1, a2, a1
 ; RV32I-NEXT:    ret
 ;
 ; RV32ZBP-LABEL: bitreverse_bswap_i64:
diff --git a/llvm/test/CodeGen/RISCV/rv64zbp.ll b/llvm/test/CodeGen/RISCV/rv64zbp.ll
--- a/llvm/test/CodeGen/RISCV/rv64zbp.ll
+++ b/llvm/test/CodeGen/RISCV/rv64zbp.ll
@@ -2351,48 +2351,27 @@
 define i32 @bitreverse_bswap_i32(i32 %a) {
 ; RV64I-LABEL: bitreverse_bswap_i32:
 ; RV64I:       # %bb.0:
-; RV64I-NEXT:    srliw a1, a0, 8
-; RV64I-NEXT:    lui a2, 16
-; RV64I-NEXT:    addiw a2, a2, -256
-; RV64I-NEXT:    and a1, a1, a2
-; RV64I-NEXT:    srliw a3, a0, 24
-; RV64I-NEXT:    or a1, a1, a3
-; RV64I-NEXT:    slli a3, a0, 8
-; RV64I-NEXT:    lui a4, 4080
-; RV64I-NEXT:    and a3, a3, a4
-; RV64I-NEXT:    slliw a0, a0, 24
-; RV64I-NEXT:    or a0, a0, a3
-; RV64I-NEXT:    or a0, a0, a1
 ; RV64I-NEXT:    srli a1, a0, 4
-; RV64I-NEXT:    lui a3, 61681
-; RV64I-NEXT:    addiw a3, a3, -241
-; RV64I-NEXT:    and a1, a1, a3
-; RV64I-NEXT:    and a0, a0, a3
+; RV64I-NEXT:    lui a2, 61681
+; RV64I-NEXT:    addiw a2, a2, -241
+; RV64I-NEXT:    and a1, a1, a2
+; RV64I-NEXT:    and a0, a0, a2
 ; RV64I-NEXT:    slliw a0, a0, 4
 ; RV64I-NEXT:    or a0, a1, a0
 ; RV64I-NEXT:    srli a1, a0, 2
-; RV64I-NEXT:    lui a3, 209715
-; RV64I-NEXT:    addiw a3, a3, 819
-; RV64I-NEXT:    and a1, a1, a3
-; RV64I-NEXT:    and a0, a0, a3
+; RV64I-NEXT:    lui a2, 209715
+; RV64I-NEXT:    addiw a2, a2, 819
+; RV64I-NEXT:    and a1, a1, a2
+; RV64I-NEXT:    and a0, a0, a2
 ; RV64I-NEXT:    slliw a0, a0, 2
 ; RV64I-NEXT:    or a0, a1, a0
 ; RV64I-NEXT:    srli a1, a0, 1
-; RV64I-NEXT:    lui a3, 349525
-; RV64I-NEXT:    addiw a3, a3, 1365
-; RV64I-NEXT:    and a1, a1, a3
-; RV64I-NEXT:    and a0, a0, a3
+; RV64I-NEXT:    lui a2, 349525
+; RV64I-NEXT:    addiw a2, a2, 1365
+; RV64I-NEXT:    and a1, a1, a2
+; RV64I-NEXT:    and a0, a0, a2
 ; RV64I-NEXT:    slliw a0, a0, 1
 ; RV64I-NEXT:    or a0, a1, a0
-; RV64I-NEXT:    srliw a1, a0, 8
-; RV64I-NEXT:    and a1, a1, a2
-; RV64I-NEXT:    srliw a2, a0, 24
-; RV64I-NEXT:    or a1, a1, a2
-; RV64I-NEXT:    slli a2, a0, 8
-; RV64I-NEXT:    and a2, a2, a4
-; RV64I-NEXT:    slliw a0, a0, 24
-; RV64I-NEXT:    or a0, a0, a2
-; RV64I-NEXT:    or a0, a0, a1
 ; RV64I-NEXT:    ret
 ;
 ; RV64ZBP-LABEL: bitreverse_bswap_i32:
@@ -2407,76 +2386,27 @@
 define i64 @bitreverse_bswap_i64(i64 %a) {
 ; RV64I-LABEL: bitreverse_bswap_i64:
 ; RV64I:       # %bb.0:
-; RV64I-NEXT:    srli a1, a0, 24
-; RV64I-NEXT:    lui a2, 4080
-; RV64I-NEXT:    and a1, a1, a2
-; RV64I-NEXT:    srli a3, a0, 8
-; RV64I-NEXT:    li a4, 255
-; RV64I-NEXT:    slli a5, a4, 24
-; RV64I-NEXT:    and a3, a3, a5
-; RV64I-NEXT:    or a1, a3, a1
-; RV64I-NEXT:    srli a3, a0, 40
-; RV64I-NEXT:    lui a6, 16
-; RV64I-NEXT:    addiw a6, a6, -256
-; RV64I-NEXT:    and a3, a3, a6
-; RV64I-NEXT:    srli a7, a0, 56
-; RV64I-NEXT:    or a3, a3, a7
-; RV64I-NEXT:    or a1, a1, a3
-; RV64I-NEXT:    slli a3, a0, 24
-; RV64I-NEXT:    slli a7, a4, 40
-; RV64I-NEXT:    and a3, a3, a7
-; RV64I-NEXT:    srliw t0, a0, 24
-; RV64I-NEXT:    slli t0, t0, 32
-; RV64I-NEXT:    or a3, a3, t0
-; RV64I-NEXT:    slli t0, a0, 40
-; RV64I-NEXT:    slli a4, a4, 48
-; RV64I-NEXT:    and t0, t0, a4
-; RV64I-NEXT:    slli a0, a0, 56
-; RV64I-NEXT:    or a0, a0, t0
-; RV64I-NEXT:    lui t0, %hi(.LCPI68_0)
-; RV64I-NEXT:    ld t0, %lo(.LCPI68_0)(t0)
-; RV64I-NEXT:    or a0, a0, a3
-; RV64I-NEXT:    or a0, a0, a1
-; RV64I-NEXT:    srli a1, a0, 4
-; RV64I-NEXT:    and a1, a1, t0
-; RV64I-NEXT:    and a0, a0, t0
-; RV64I-NEXT:    lui a3, %hi(.LCPI68_1)
-; RV64I-NEXT:    ld a3, %lo(.LCPI68_1)(a3)
+; RV64I-NEXT:    lui a1, %hi(.LCPI68_0)
+; RV64I-NEXT:    ld a1, %lo(.LCPI68_0)(a1)
+; RV64I-NEXT:    srli a2, a0, 4
+; RV64I-NEXT:    and a2, a2, a1
+; RV64I-NEXT:    and a0, a0, a1
+; RV64I-NEXT:    lui a1, %hi(.LCPI68_1)
+; RV64I-NEXT:    ld a1, %lo(.LCPI68_1)(a1)
 ; RV64I-NEXT:    slli a0, a0, 4
-; RV64I-NEXT:    or a0, a1, a0
-; RV64I-NEXT:    srli a1, a0, 2
-; RV64I-NEXT:    and a1, a1, a3
-; RV64I-NEXT:    and a0, a0, a3
-; RV64I-NEXT:    lui a3, %hi(.LCPI68_2)
-; RV64I-NEXT:    ld a3, %lo(.LCPI68_2)(a3)
+; RV64I-NEXT:    or a0, a2, a0
+; RV64I-NEXT:    srli a2, a0, 2
+; RV64I-NEXT:    and a2, a2, a1
+; RV64I-NEXT:    and a0, a0, a1
+; RV64I-NEXT:    lui a1, %hi(.LCPI68_2)
+; RV64I-NEXT:    ld a1, %lo(.LCPI68_2)(a1)
 ; RV64I-NEXT:    slli a0, a0, 2
-; RV64I-NEXT:    or a0, a1, a0
-; RV64I-NEXT:    srli a1, a0, 1
-; RV64I-NEXT:    and a1, a1, a3
-; RV64I-NEXT:    and a0, a0, a3
+; RV64I-NEXT:    or a0, a2, a0
+; RV64I-NEXT:    srli a2, a0, 1
+; RV64I-NEXT:    and a2, a2, a1
+; RV64I-NEXT:    and a0, a0, a1
 ; RV64I-NEXT:    slli a0, a0, 1
-; RV64I-NEXT:    or a0, a1, a0
-; RV64I-NEXT:    srli a1, a0, 40
-; RV64I-NEXT:    and a1, a1, a6
-; RV64I-NEXT:    srli a3, a0, 56
-; RV64I-NEXT:    or a1, a1, a3
-; RV64I-NEXT:    srli a3, a0, 24
-; RV64I-NEXT:    and a2, a3, a2
-; RV64I-NEXT:    srli a3, a0, 8
-; RV64I-NEXT:    and a3, a3, a5
-; RV64I-NEXT:    or a2, a3, a2
-; RV64I-NEXT:    or a1, a2, a1
-; RV64I-NEXT:    slli a2, a0, 24
-; RV64I-NEXT:    and a2, a2, a7
-; RV64I-NEXT:    srliw a3, a0, 24
-; RV64I-NEXT:    slli a3, a3, 32
-; RV64I-NEXT:    or a2, a2, a3
-; RV64I-NEXT:    slli a3, a0, 40
-; RV64I-NEXT:    and a3, a3, a4
-; RV64I-NEXT:    slli a0, a0, 56
-; RV64I-NEXT:    or a0, a0, a3
-; RV64I-NEXT:    or a0, a0, a2
-; RV64I-NEXT:    or a0, a0, a1
+; RV64I-NEXT:    or a0, a2, a0
 ; RV64I-NEXT:    ret
 ;
 ; RV64ZBP-LABEL: bitreverse_bswap_i64: