diff --git a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
--- a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
+++ b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
@@ -151,9 +151,12 @@
   setOperationAction(ISD::ROTL, XLenVT, Expand);
   setOperationAction(ISD::ROTR, XLenVT, Expand);
   setOperationAction(ISD::BSWAP, XLenVT, Expand);
-  setOperationAction(ISD::CTTZ, XLenVT, Expand);
-  setOperationAction(ISD::CTLZ, XLenVT, Expand);
-  setOperationAction(ISD::CTPOP, XLenVT, Expand);
+
+  if (!Subtarget.hasStdExtZbb()) {
+    setOperationAction(ISD::CTTZ, XLenVT, Expand);
+    setOperationAction(ISD::CTLZ, XLenVT, Expand);
+    setOperationAction(ISD::CTPOP, XLenVT, Expand);
+  }
 
   ISD::CondCode FPCCToExtend[] = {
       ISD::SETOGT, ISD::SETOGE, ISD::SETONE, ISD::SETUEQ, ISD::SETUGT,
diff --git a/llvm/lib/Target/RISCV/RISCVInstrInfoB.td b/llvm/lib/Target/RISCV/RISCVInstrInfoB.td
--- a/llvm/lib/Target/RISCV/RISCVInstrInfoB.td
+++ b/llvm/lib/Target/RISCV/RISCVInstrInfoB.td
@@ -632,3 +632,55 @@
 def : CompressPat<(PACK GPRC:$rs1, GPRC:$rs1, X0),
                   (C_ZEXTW GPRC:$rs1)>;
 } // Predicates = [HasStdExtZbproposedc, HasStdExtC, IsRV64]
+
+//===----------------------------------------------------------------------===//
+// Codegen patterns
+//===----------------------------------------------------------------------===//
+
+let Predicates = [HasStdExtZbb] in {
+def : Pat<(xor (shl (xor GPR:$rs1, -1), GPR:$rs2), -1),
+          (SLO GPR:$rs1, GPR:$rs2)>;
+def : Pat<(xor (srl (xor GPR:$rs1, -1), GPR:$rs2), -1),
+          (SRO GPR:$rs1, GPR:$rs2)>;
+def : Pat<(ctlz GPR:$rs1), (CLZ GPR:$rs1)>;
+def : Pat<(cttz GPR:$rs1), (CTZ GPR:$rs1)>;
+def : Pat<(ctpop GPR:$rs1), (PCNT GPR:$rs1)>;
+} // Predicates = [HasStdExtZbb]
+
+let Predicates = [HasStdExtZbb, IsRV32] in
+def : Pat<(sra (shl GPR:$rs1, (i32 24)), (i32 24)), (SEXTB GPR:$rs1)>;
+let Predicates = [HasStdExtZbb, IsRV64] in
+def : Pat<(sra (shl GPR:$rs1, (i64 56)), (i64 56)), (SEXTB GPR:$rs1)>;
+
+let Predicates = [HasStdExtZbb, IsRV32] in
+def : Pat<(sra (shl GPR:$rs1, (i32 16)), (i32 16)), (SEXTH GPR:$rs1)>;
+let Predicates = [HasStdExtZbb, IsRV64] in
+def : Pat<(sra (shl GPR:$rs1, (i64 48)), (i64 48)), (SEXTH GPR:$rs1)>;
+
+let Predicates = [HasStdExtZbb] in {
+def : Pat<(smin GPR:$rs1, GPR:$rs2), (MIN  GPR:$rs1, GPR:$rs2)>;
+def : Pat<(riscv_selectcc GPR:$rs1, GPR:$rs2, (XLenVT 20), GPR:$rs1, GPR:$rs2),
+          (MIN  GPR:$rs1, GPR:$rs2)>;
+def : Pat<(smax GPR:$rs1, GPR:$rs2), (MAX  GPR:$rs1, GPR:$rs2)>;
+def : Pat<(riscv_selectcc GPR:$rs2, GPR:$rs1, (XLenVT 20), GPR:$rs1, GPR:$rs2),
+          (MAX  GPR:$rs1, GPR:$rs2)>;
+def : Pat<(umin GPR:$rs1, GPR:$rs2), (MINU GPR:$rs1, GPR:$rs2)>;
+def : Pat<(riscv_selectcc GPR:$rs1, GPR:$rs2, (XLenVT 12), GPR:$rs1, GPR:$rs2),
+          (MINU  GPR:$rs1, GPR:$rs2)>;
+def : Pat<(umax GPR:$rs1, GPR:$rs2), (MAXU GPR:$rs1, GPR:$rs2)>;
+def : Pat<(riscv_selectcc GPR:$rs2, GPR:$rs1, (XLenVT 12), GPR:$rs1, GPR:$rs2),
+          (MAXU  GPR:$rs1, GPR:$rs2)>;
+} // Predicates = [HasStdExtZbb]
+
+let Predicates = [HasStdExtZbb, IsRV64] in {
+def : Pat<(and (add GPR:$rs, simm12:$simm12), 0xFFFFFFFF),
+          (ADDIWU GPR:$rs, simm12:$simm12)>;
+def : Pat<(and (add GPR:$rs1, GPR:$rs2), 0xFFFFFFFF),
+          (ADDWU GPR:$rs1, GPR:$rs2)>;
+def : Pat<(and (sub GPR:$rs1, GPR:$rs2), 0xFFFFFFFF),
+          (SUBWU GPR:$rs1, GPR:$rs2)>;
+def : Pat<(add GPR:$rs1, (and GPR:$rs2, 0xFFFFFFFF)),
+          (ADDUW GPR:$rs1, GPR:$rs2)>;
+def : Pat<(sub GPR:$rs1, (and GPR:$rs2, 0xFFFFFFFF)),
+          (SUBUW GPR:$rs1, GPR:$rs2)>;
+} // Predicates = [HasStdExtZbb, IsRV64]
diff --git a/llvm/test/CodeGen/RISCV/rv32Zbb.ll b/llvm/test/CodeGen/RISCV/rv32Zbb.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/CodeGen/RISCV/rv32Zbb.ll
@@ -0,0 +1,153 @@
+; RUN: llc -mtriple=riscv32 -verify-machineinstrs < %s \
+; RUN:   | FileCheck %s -check-prefix=RV32I
+; RUN: llc -mtriple=riscv32 -mattr=+experimental-b -verify-machineinstrs < %s \
+; RUN:   | FileCheck %s -check-prefix=RV32IB
+; RUN: llc -mtriple=riscv32 -mattr=+experimental-zbb -verify-machineinstrs < %s \
+; RUN:   | FileCheck %s -check-prefix=RV32IB
+
+define i32 @slo(i32 %a, i32 %b) nounwind {
+; RV32I-NOT:    slo a0, a0, a1
+;
+; RV32IB-LABEL: slo:
+; RV32IB:       # %bb.0:
+; RV32IB-NEXT:    slo a0, a0, a1
+; RV32IB-NEXT:    ret
+  %neg = xor i32 %a, -1
+  %shl = shl i32 %neg, %b
+  %neg1 = xor i32 %shl, -1
+  ret i32 %neg1
+}
+
+define i32 @sro(i32 %a, i32 %b) nounwind {
+; RV32I-NOT:    sro a0, a0, a1
+;
+; RV32IB-LABEL: sro:
+; RV32IB:       # %bb.0:
+; RV32IB-NEXT:    sro a0, a0, a1
+; RV32IB-NEXT:    ret
+  %neg = xor i32 %a, -1
+  %shr = lshr i32 %neg, %b
+  %neg1 = xor i32 %shr, -1
+  ret i32 %neg1
+}
+
+declare i32 @llvm.ctlz.i32(i32, i1)
+
+define i32 @ctlz_i32(i32 %a) nounwind {
+; RV32I-NOT:    clz a0, a0
+;
+; RV32IB-LABEL: ctlz_i32:
+; RV32IB:       # %bb.0:
+; RV32IB-NEXT:    beqz a0, .LBB2_2
+; RV32IB-NEXT:  # %bb.1: # %cond.false
+; RV32IB-NEXT:    clz a0, a0
+; RV32IB-NEXT:    ret
+; RV32IB-NEXT:  .LBB2_2:
+; RV32IB-NEXT:    addi a0, zero, 32
+; RV32IB-NEXT:    ret
+  %1 = call i32 @llvm.ctlz.i32(i32 %a, i1 false)
+  ret i32 %1
+}
+
+declare i32 @llvm.cttz.i32(i32, i1)
+
+define i32 @cttz_i32(i32 %a) nounwind {
+; RV32I-NOT:    ctz a0, a0
+;
+; RV32IB-LABEL: cttz_i32:
+; RV32IB:       # %bb.0:
+; RV32IB-NEXT:    beqz a0, .LBB3_2
+; RV32IB-NEXT:  # %bb.1: # %cond.false
+; RV32IB-NEXT:    ctz a0, a0
+; RV32IB-NEXT:    ret
+; RV32IB-NEXT:  .LBB3_2:
+; RV32IB-NEXT:    addi a0, zero, 32
+; RV32IB-NEXT:    ret
+  %1 = call i32 @llvm.cttz.i32(i32 %a, i1 false)
+  ret i32 %1
+}
+
+declare i32 @llvm.ctpop.i32(i32)
+
+define i32 @ctpop_i32(i32 %a) nounwind {
+; RV32I-NOT:    pcnt a0, a0
+;
+; RV32IB-LABEL: ctpop_i32:
+; RV32IB:       # %bb.0:
+; RV32IB-NEXT:    pcnt a0, a0
+; RV32IB-NEXT:    ret
+  %1 = call i32 @llvm.ctpop.i32(i32 %a)
+  ret i32 %1
+}
+
+define i32 @sextb(i32 %a) nounwind {
+; RV32I-NOT:    sext.b a0, a0
+;
+; RV32IB-LABEL: sextb:
+; RV32IB:       # %bb.0:
+; RV32IB-NEXT:    sext.b a0, a0
+; RV32IB-NEXT:    ret
+  %shl = shl i32 %a, 24
+  %shr = ashr exact i32 %shl, 24
+  ret i32 %shr
+}
+
+define i32 @sexth(i32 %a) nounwind {
+; RV32I-NOT:    sext.h a0, a0
+;
+; RV32IB-LABEL: sexth:
+; RV32IB:       # %bb.0:
+; RV32IB-NEXT:    sext.h a0, a0
+; RV32IB-NEXT:    ret
+  %shl = shl i32 %a, 16
+  %shr = ashr exact i32 %shl, 16
+  ret i32 %shr
+}
+
+define i32 @min(i32 %a, i32 %b) nounwind {
+; RV32I-NOT:    min a0, a0, a1
+;
+; RV32IB-LABEL: min:
+; RV32IB:       # %bb.0:
+; RV32IB-NEXT:    min a0, a0, a1
+; RV32IB-NEXT:    ret
+  %cmp = icmp slt i32 %a, %b
+  %cond = select i1 %cmp, i32 %a, i32 %b
+  ret i32 %cond
+}
+
+define i32 @max(i32 %a, i32 %b) nounwind {
+; RV32I-NOT:    max a0, a0, a1
+;
+; RV32IB-LABEL: max:
+; RV32IB:       # %bb.0:
+; RV32IB-NEXT:    max a0, a0, a1
+; RV32IB-NEXT:    ret
+  %cmp = icmp sgt i32 %a, %b
+  %cond = select i1 %cmp, i32 %a, i32 %b
+  ret i32 %cond
+}
+
+define i32 @minu(i32 %a, i32 %b) nounwind {
+; RV32I-NOT:    minu a0, a0, a1
+;
+; RV32IB-LABEL: minu:
+; RV32IB:       # %bb.0:
+; RV32IB-NEXT:    minu a0, a0, a1
+; RV32IB-NEXT:    ret
+  %cmp = icmp ult i32 %a, %b
+  %cond = select i1 %cmp, i32 %a, i32 %b
+  ret i32 %cond
+}
+
+define i32 @maxu(i32 %a, i32 %b) nounwind {
+; RV32I-NOT:    maxu a0, a0, a1
+;
+; RV32IB-LABEL: maxu:
+; RV32IB:       # %bb.0:
+; RV32IB-NEXT:    maxu a0, a0, a1
+; RV32IB-NEXT:    ret
+  %cmp = icmp ugt i32 %a, %b
+  %cond = select i1 %cmp, i32 %a, i32 %b
+  ret i32 %cond
+}
diff --git a/llvm/test/CodeGen/RISCV/rv64Zbb.ll b/llvm/test/CodeGen/RISCV/rv64Zbb.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/CodeGen/RISCV/rv64Zbb.ll
@@ -0,0 +1,213 @@
+; RUN: llc -mtriple=riscv64 -verify-machineinstrs < %s \
+; RUN:   | FileCheck %s -check-prefix=RV64I
+; RUN: llc -mtriple=riscv64 -mattr=+experimental-b -verify-machineinstrs < %s \
+; RUN:   | FileCheck %s -check-prefix=RV64IB
+; RUN: llc -mtriple=riscv64 -mattr=+experimental-zbb -verify-machineinstrs < %s \
+; RUN:   | FileCheck %s -check-prefix=RV64IB
+
+define i64 @slo(i64 %a, i64 %b) nounwind {
+; RV64I-NOT:    slo a0, a0, a1
+;
+; RV64IB-LABEL: slo:
+; RV64IB:       # %bb.0:
+; RV64IB-NEXT:    slo a0, a0, a1
+; RV64IB-NEXT:    ret
+  %neg = xor i64 %a, -1
+  %shl = shl i64 %neg, %b
+  %neg1 = xor i64 %shl, -1
+  ret i64 %neg1
+}
+
+define i64 @sro(i64 %a, i64 %b) nounwind {
+; RV64I-NOT:    sro a0, a0, a1
+;
+; RV64IB-LABEL: sro:
+; RV64IB:       # %bb.0:
+; RV64IB-NEXT:    sro a0, a0, a1
+; RV64IB-NEXT:    ret
+  %neg = xor i64 %a, -1
+  %shr = lshr i64 %neg, %b
+  %neg1 = xor i64 %shr, -1
+  ret i64 %neg1
+}
+
+declare i64 @llvm.ctlz.i64(i64, i1)
+
+define i64 @ctlz_i64(i64 %a) nounwind {
+; RV64I-NOT:    clz a0, a0
+;
+; RV64IB-LABEL: ctlz_i64:
+; RV64IB:       # %bb.0:
+; RV64IB-NEXT:    beqz a0, .LBB2_2
+; RV64IB-NEXT:  # %bb.1: # %cond.false
+; RV64IB-NEXT:    clz a0, a0
+; RV64IB-NEXT:    ret
+; RV64IB-NEXT:  .LBB2_2:
+; RV64IB-NEXT:    addi a0, zero, 64
+; RV64IB-NEXT:    ret
+  %1 = call i64 @llvm.ctlz.i64(i64 %a, i1 false)
+  ret i64 %1
+}
+
+declare i64 @llvm.cttz.i64(i64, i1)
+
+define i64 @cttz_i64(i64 %a) nounwind {
+; RV64I-NOT:    ctz a0, a0
+;
+; RV64IB-LABEL: cttz_i64:
+; RV64IB:       # %bb.0:
+; RV64IB-NEXT:    beqz a0, .LBB3_2
+; RV64IB-NEXT:  # %bb.1: # %cond.false
+; RV64IB-NEXT:    ctz a0, a0
+; RV64IB-NEXT:    ret
+; RV64IB-NEXT:  .LBB3_2:
+; RV64IB-NEXT:    addi a0, zero, 64
+; RV64IB-NEXT:    ret
+  %1 = call i64 @llvm.cttz.i64(i64 %a, i1 false)
+  ret i64 %1
+}
+
+declare i64 @llvm.ctpop.i64(i64)
+
+define i64 @ctpop_i64(i64 %a) nounwind {
+; RV64I-NOT:    pcnt a0, a0
+;
+; RV64IB-LABEL: ctpop_i64:
+; RV64IB:       # %bb.0:
+; RV64IB-NEXT:    pcnt a0, a0
+; RV64IB-NEXT:    ret
+  %1 = call i64 @llvm.ctpop.i64(i64 %a)
+  ret i64 %1
+}
+
+define i64 @sextb(i64 %a) nounwind {
+; RV64I-NOT:    sext.b a0, a0
+;
+; RV64IB-LABEL: sextb:
+; RV64IB:       # %bb.0:
+; RV64IB-NEXT:    sext.b a0, a0
+; RV64IB-NEXT:    ret
+  %shl = shl i64 %a, 56
+  %shr = ashr exact i64 %shl, 56
+  ret i64 %shr
+}
+
+define i64 @sexth(i64 %a) nounwind {
+; RV64I-NOT:    sext.h a0, a0
+;
+; RV64IB-LABEL: sexth:
+; RV64IB:       # %bb.0:
+; RV64IB-NEXT:    sext.h a0, a0
+; RV64IB-NEXT:    ret
+  %shl = shl i64 %a, 48
+  %shr = ashr exact i64 %shl, 48
+  ret i64 %shr
+}
+
+define i64 @min(i64 %a, i64 %b) nounwind {
+; RV64I-NOT:    min a0, a0, a1
+;
+; RV64IB-LABEL: min:
+; RV64IB:       # %bb.0:
+; RV64IB-NEXT:    min a0, a0, a1
+; RV64IB-NEXT:    ret
+  %cmp = icmp slt i64 %a, %b
+  %cond = select i1 %cmp, i64 %a, i64 %b
+  ret i64 %cond
+}
+
+define i64 @max(i64 %a, i64 %b) nounwind {
+; RV64I-NOT:    max a0, a0, a1
+;
+; RV64IB-LABEL: max:
+; RV64IB:       # %bb.0:
+; RV64IB-NEXT:    max a0, a0, a1
+; RV64IB-NEXT:    ret
+  %cmp = icmp sgt i64 %a, %b
+  %cond = select i1 %cmp, i64 %a, i64 %b
+  ret i64 %cond
+}
+
+define i64 @minu(i64 %a, i64 %b) nounwind {
+; RV64I-NOT:    minu a0, a0, a1
+;
+; RV64IB-LABEL: minu:
+; RV64IB:       # %bb.0:
+; RV64IB-NEXT:    minu a0, a0, a1
+; RV64IB-NEXT:    ret
+  %cmp = icmp ult i64 %a, %b
+  %cond = select i1 %cmp, i64 %a, i64 %b
+  ret i64 %cond
+}
+
+define i64 @maxu(i64 %a, i64 %b) nounwind {
+; RV64I-NOT:    maxu a0, a0, a1
+;
+; RV64IB-LABEL: maxu:
+; RV64IB:       # %bb.0:
+; RV64IB-NEXT:    maxu a0, a0, a1
+; RV64IB-NEXT:    ret
+  %cmp = icmp ugt i64 %a, %b
+  %cond = select i1 %cmp, i64 %a, i64 %b
+  ret i64 %cond
+}
+
+define i64 @addiwu(i64 %a) nounwind {
+; RV64I-NOT:    addiwu a0, a0, 1
+;
+; RV64IB-LABEL: addiwu:
+; RV64IB:       # %bb.0:
+; RV64IB-NEXT:    addiwu a0, a0, 1
+; RV64IB-NEXT:    ret
+  %conv = add i64 %a, 1
+  %conv1 = and i64 %conv, 4294967295
+  ret i64 %conv1
+}
+
+define i64 @addwu(i64 %a, i64 %b) nounwind {
+; RV64I-NOT:    addwu a0, a1, a0
+;
+; RV64IB-LABEL: addwu:
+; RV64IB:       # %bb.0:
+; RV64IB-NEXT:    addwu a0, a1, a0
+; RV64IB-NEXT:    ret
+  %add = add i64 %b, %a
+  %conv1 = and i64 %add, 4294967295
+  ret i64 %conv1
+}
+
+define i64 @subwu(i64 %a, i64 %b) nounwind {
+; RV64I-NOT:    subwu a0, a0, a1
+;
+; RV64IB-LABEL: subwu:
+; RV64IB:       # %bb.0:
+; RV64IB-NEXT:    subwu a0, a0, a1
+; RV64IB-NEXT:    ret
+  %sub = sub i64 %a, %b
+  %conv1 = and i64 %sub, 4294967295
+  ret i64 %conv1
+}
+
+define i64 @adduw(i64 %a, i64 %b) nounwind {
+; RV64I-NOT:    addu.w a0, a0, a1
+;
+; RV64IB-LABEL: adduw:
+; RV64IB:       # %bb.0:
+; RV64IB-NEXT:    addu.w a0, a0, a1
+; RV64IB-NEXT:    ret
+  %and = and i64 %b, 4294967295
+  %add = add i64 %and, %a
+  ret i64 %add
+}
+
+define i64 @subuw(i64 %a, i64 %b) nounwind {
+; RV64I-NOT:    subu.w a0, a0, a1
+;
+; RV64IB-LABEL: subuw:
+; RV64IB:       # %bb.0:
+; RV64IB-NEXT:    subu.w a0, a0, a1
+; RV64IB-NEXT:    ret
+  %and = and i64 %b, 4294967295
+  %sub = sub i64 %a, %and
+  ret i64 %sub
+}