Index: llvm/lib/Target/RISCV/RISCVISelLowering.h
===================================================================
--- llvm/lib/Target/RISCV/RISCVISelLowering.h
+++ llvm/lib/Target/RISCV/RISCVISelLowering.h
@@ -372,6 +372,7 @@
   bool signExtendConstant(const ConstantInt *CI) const override;
   bool isCheapToSpeculateCttz() const override;
   bool isCheapToSpeculateCtlz() const override;
+  bool isMaskAndCmp0FoldingBeneficial(const Instruction &AndI) const override;
   bool hasAndNotCompare(SDValue Y) const override;
   bool hasBitTest(SDValue X, SDValue Y) const override;
   bool shouldProduceAndByConstByHoistingConstFromShiftsLHSOfAnd(
Index: llvm/lib/Target/RISCV/RISCVISelLowering.cpp
===================================================================
--- llvm/lib/Target/RISCV/RISCVISelLowering.cpp
+++ llvm/lib/Target/RISCV/RISCVISelLowering.cpp
@@ -1140,6 +1140,22 @@
   return Subtarget.hasStdExtZbb();
 }
 
+bool RISCVTargetLowering::isMaskAndCmp0FoldingBeneficial(
+    const Instruction &AndI) const {
+  // We expect to be able to match a bit extraction instruction if the Zbs
+  // extension is supported and the mask is a power of two. However, we
+  // conservatively return false if the mask would bit in an ANDI instruction,
+  // on the basis that it's possible the fold wouldn't decrease the
+  // instruction count and would increase code size (e.g. ANDI+BNEZ =>
+  // BEXTI+BNEZ).
+  if (!Subtarget.hasStdExtZbs())
+    return false;
+  ConstantInt* Mask = dyn_cast<ConstantInt>(AndI.getOperand(1));
+  if (!Mask)
+    return false;
+  return !Mask->getValue().isSignedIntN(12) && Mask->getValue().isPowerOf2();
+}
+
 bool RISCVTargetLowering::hasAndNotCompare(SDValue Y) const {
   EVT VT = Y.getValueType();
 
Index: llvm/test/Transforms/CodeGenPrepare/RISCV/and-mask-sink.ll
===================================================================
--- /dev/null
+++ llvm/test/Transforms/CodeGenPrepare/RISCV/and-mask-sink.ll
@@ -0,0 +1,88 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -S -codegenprepare -mtriple=riscv32 %s \
+; RUN:   | FileCheck --check-prefixes=CHECK,NOZBS %s
+; RUN: opt -S -codegenprepare -mtriple=riscv32 -mattr=+zbs %s \
+; RUN:   | FileCheck --check-prefixes=CHECK,ZBS %s
+; RUN: opt -S -codegenprepare -mtriple=riscv64 %s \
+; RUN:   | FileCheck --check-prefixes=CHECK,NOZBS %s
+; RUN: opt -S -codegenprepare -mtriple=riscv64 -mattr=zbs %s \
+; RUN:   | FileCheck --check-prefixes=CHECK,ZBS %s
+
+@A = global i32 zeroinitializer
+
+; And should be sunk when Zbs is present and the mask doesn't fit in ANDI's
+; immediate.
+define i32 @and_sink1(i32 %a, i1 %c) {
+; NOZBS-LABEL: @and_sink1(
+; NOZBS-NEXT:    [[AND:%.*]] = and i32 [[A:%.*]], 2048
+; NOZBS-NEXT:    br label [[BB0:%.*]]
+; NOZBS:       bb0:
+; NOZBS-NEXT:    [[CMP:%.*]] = icmp eq i32 [[AND]], 0
+; NOZBS-NEXT:    store i32 0, i32* @A, align 4
+; NOZBS-NEXT:    br i1 [[CMP]], label [[BB0]], label [[BB2:%.*]]
+; NOZBS:       bb2:
+; NOZBS-NEXT:    ret i32 0
+;
+; ZBS-LABEL: @and_sink1(
+; ZBS-NEXT:    br label [[BB0:%.*]]
+; ZBS:       bb0:
+; ZBS-NEXT:    [[TMP1:%.*]] = and i32 [[A:%.*]], 2048
+; ZBS-NEXT:    [[CMP:%.*]] = icmp eq i32 [[TMP1]], 0
+; ZBS-NEXT:    store i32 0, i32* @A, align 4
+; ZBS-NEXT:    br i1 [[CMP]], label [[BB0]], label [[BB2:%.*]]
+; ZBS:       bb2:
+; ZBS-NEXT:    ret i32 0
+;
+  %and = and i32 %a, 2048
+  br label %bb0
+bb0:
+  %cmp = icmp eq i32 %and, 0
+  store i32 0, i32* @A
+  br i1 %cmp, label %bb0, label %bb2
+bb2:
+  ret i32 0
+}
+
+; Don't sink when the mask has more than 1 bit set.
+define i32 @and_sink2(i32 %a) {
+; CHECK-LABEL: @and_sink2(
+; CHECK-NEXT:    [[AND:%.*]] = and i32 [[A:%.*]], 2049
+; CHECK-NEXT:    br label [[BB0:%.*]]
+; CHECK:       bb0:
+; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i32 [[AND]], 0
+; CHECK-NEXT:    store i32 0, i32* @A, align 4
+; CHECK-NEXT:    br i1 [[CMP]], label [[BB0]], label [[BB2:%.*]]
+; CHECK:       bb2:
+; CHECK-NEXT:    ret i32 0
+;
+  %and = and i32 %a, 2049
+  br label %bb0
+bb0:
+  %cmp = icmp eq i32 %and, 0
+  store i32 0, i32* @A
+  br i1 %cmp, label %bb0, label %bb2
+bb2:
+  ret i32 0
+}
+
+; Don't sink when the mask fits in ANDI's immediate.
+define i32 @and_sink3(i32 %a) {
+; CHECK-LABEL: @and_sink3(
+; CHECK-NEXT:    [[AND:%.*]] = and i32 [[A:%.*]], 1024
+; CHECK-NEXT:    br label [[BB0:%.*]]
+; CHECK:       bb0:
+; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i32 [[AND]], 0
+; CHECK-NEXT:    store i32 0, i32* @A, align 4
+; CHECK-NEXT:    br i1 [[CMP]], label [[BB0]], label [[BB2:%.*]]
+; CHECK:       bb2:
+; CHECK-NEXT:    ret i32 0
+;
+  %and = and i32 %a, 1024
+  br label %bb0
+bb0:
+  %cmp = icmp eq i32 %and, 0
+  store i32 0, i32* @A
+  br i1 %cmp, label %bb0, label %bb2
+bb2:
+  ret i32 0
+}