diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
index 669d4f0f45714..8d9933bfab938 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -582,6 +582,18 @@ static Instruction *foldCttzCtlz(IntrinsicInst &II, InstCombinerImpl &IC) {
           IC.Builder.CreateBinaryIntrinsic(Intrinsic::ctlz, C, Op1);
       return BinaryOperator::CreateSub(ConstCtlz, X);
     }
+
+    // ctlz(~x & (x - 1)) -> bitwidth - cttz(x, false)
+    if (Op0->hasOneUse() &&
+        match(Op0,
+              m_c_And(m_Not(m_Value(X)), m_Add(m_Deferred(X), m_AllOnes())))) {
+      Type *Ty = II.getType();
+      unsigned BitWidth = Ty->getScalarSizeInBits();
+      auto *Cttz = IC.Builder.CreateIntrinsic(Intrinsic::cttz, Ty,
+                                              {X, IC.Builder.getFalse()});
+      auto *Bw = ConstantInt::get(Ty, APInt(BitWidth, BitWidth));
+      return IC.replaceInstUsesWith(II, IC.Builder.CreateSub(Bw, Cttz));
+    }
   }
 
   // cttz(Pow2) -> Log2(Pow2)
diff --git a/llvm/test/Transforms/InstCombine/ctlz-cttz.ll b/llvm/test/Transforms/InstCombine/ctlz-cttz.ll
new file mode 100644
index 0000000000000..871fb342360fd
--- /dev/null
+++ b/llvm/test/Transforms/InstCombine/ctlz-cttz.ll
@@ -0,0 +1,145 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 6
+; RUN: opt < %s -S -passes=instcombine | FileCheck %s
+
+; ctpop(~i & (i - 1)) -> bitwidth - cttz(i, false)
+define i8 @ctlz_to_sub_bw_cttz(i8 %a0) {
+; CHECK-LABEL: define i8 @ctlz_to_sub_bw_cttz(
+; CHECK-SAME: i8 [[A0:%.*]]) {
+; CHECK-NEXT:    [[TMP1:%.*]] = call range(i8 0, 9) i8 @llvm.cttz.i8(i8 [[A0]], i1 false)
+; CHECK-NEXT:    [[CLZ:%.*]] = sub nuw nsw i8 8, [[TMP1]]
+; CHECK-NEXT:    ret i8 [[CLZ]]
+;
+  %dec = add i8 %a0, -1
+  %not = xor i8 %a0, -1
+  %and = and i8 %dec, %not
+  %clz = tail call i8 @llvm.ctlz.i8(i8 %and, i1 false)
+  ret i8 %clz
+}
+
+define i8 @ctlz_to_sub_bw_cttz_poison(i8 %a0) {
+; CHECK-LABEL: define i8 @ctlz_to_sub_bw_cttz_poison(
+; CHECK-SAME: i8 [[A0:%.*]]) {
+; CHECK-NEXT:    [[TMP1:%.*]] = call range(i8 0, 9) i8 @llvm.cttz.i8(i8 [[A0]], i1 false)
+; CHECK-NEXT:    [[CLZ:%.*]] = sub nuw nsw i8 8, [[TMP1]]
+; CHECK-NEXT:    ret i8 [[CLZ]]
+;
+  %dec = add i8 %a0, -1
+  %not = xor i8 %a0, -1
+  %and = and i8 %dec, %not
+  %clz = tail call i8 @llvm.ctlz.i8(i8 %and, i1 true)
+  ret i8 %clz
+}
+
+define i8 @ctlz_to_sub_bw_cttz_different_add(i8 %a0) {
+; CHECK-LABEL: define i8 @ctlz_to_sub_bw_cttz_different_add(
+; CHECK-SAME: i8 [[A0:%.*]]) {
+; CHECK-NEXT:    [[DEC:%.*]] = add i8 [[A0]], 1
+; CHECK-NEXT:    [[NOT:%.*]] = xor i8 [[A0]], -1
+; CHECK-NEXT:    [[AND:%.*]] = and i8 [[DEC]], [[NOT]]
+; CHECK-NEXT:    [[CLZ:%.*]] = tail call range(i8 0, 9) i8 @llvm.ctlz.i8(i8 [[AND]], i1 false)
+; CHECK-NEXT:    ret i8 [[CLZ]]
+;
+  %dec = add i8 %a0, 1
+  %not = xor i8 %a0, -1
+  %and = and i8 %dec, %not
+  %clz = tail call i8 @llvm.ctlz.i8(i8 %and, i1 false)
+  ret i8 %clz
+}
+
+define i8 @ctlz_to_sub_bw_cttz_different_xor(i8 %a0) {
+; CHECK-LABEL: define i8 @ctlz_to_sub_bw_cttz_different_xor(
+; CHECK-SAME: i8 [[A0:%.*]]) {
+; CHECK-NEXT:    [[DEC:%.*]] = add i8 [[A0]], -1
+; CHECK-NEXT:    [[NOT:%.*]] = xor i8 [[A0]], 1
+; CHECK-NEXT:    [[AND:%.*]] = and i8 [[DEC]], [[NOT]]
+; CHECK-NEXT:    [[CLZ:%.*]] = tail call range(i8 0, 9) i8 @llvm.ctlz.i8(i8 [[AND]], i1 false)
+; CHECK-NEXT:    ret i8 [[CLZ]]
+;
+  %dec = add i8 %a0, -1
+  %not = xor i8 %a0, 1
+  %and = and i8 %dec, %not
+  %clz = tail call i8 @llvm.ctlz.i8(i8 %and, i1 false)
+  ret i8 %clz
+}
+
+declare void @use(i8)
+
+define i8 @ctlz_to_sub_bw_cttz_multi_use_dec(i8 %a0) {
+; CHECK-LABEL: define i8 @ctlz_to_sub_bw_cttz_multi_use_dec(
+; CHECK-SAME: i8 [[A0:%.*]]) {
+; CHECK-NEXT:    [[DEC:%.*]] = add i8 [[A0]], -1
+; CHECK-NEXT:    call void @use(i8 [[DEC]])
+; CHECK-NEXT:    [[TMP1:%.*]] = call range(i8 0, 9) i8 @llvm.cttz.i8(i8 [[A0]], i1 false)
+; CHECK-NEXT:    [[CLZ:%.*]] = sub nuw nsw i8 8, [[TMP1]]
+; CHECK-NEXT:    ret i8 [[CLZ]]
+;
+  %dec = add i8 %a0, -1
+  call void @use(i8 %dec)
+  %not = xor i8 %a0, -1
+  %and = and i8 %dec, %not
+  %clz = tail call i8 @llvm.ctlz.i8(i8 %and, i1 false)
+  ret i8 %clz
+}
+
+define i8 @ctlz_to_sub_bw_cttz_multi_use_not(i8 %a0) {
+; CHECK-LABEL: define i8 @ctlz_to_sub_bw_cttz_multi_use_not(
+; CHECK-SAME: i8 [[A0:%.*]]) {
+; CHECK-NEXT:    [[NOT:%.*]] = xor i8 [[A0]], -1
+; CHECK-NEXT:    call void @use(i8 [[NOT]])
+; CHECK-NEXT:    [[TMP1:%.*]] = call range(i8 0, 9) i8 @llvm.cttz.i8(i8 [[A0]], i1 false)
+; CHECK-NEXT:    [[CLZ:%.*]] = sub nuw nsw i8 8, [[TMP1]]
+; CHECK-NEXT:    ret i8 [[CLZ]]
+;
+  %dec = add i8 %a0, -1
+  %not = xor i8 %a0, -1
+  call void @use(i8 %not)
+  %and = and i8 %dec, %not
+  %clz = tail call i8 @llvm.ctlz.i8(i8 %and, i1 false)
+  ret i8 %clz
+}
+
+define i8 @ctlz_to_sub_bw_cttz_multi_use_and(i8 %a0) {
+; CHECK-LABEL: define i8 @ctlz_to_sub_bw_cttz_multi_use_and(
+; CHECK-SAME: i8 [[A0:%.*]]) {
+; CHECK-NEXT:    [[DEC:%.*]] = add i8 [[A0]], -1
+; CHECK-NEXT:    [[NOT:%.*]] = xor i8 [[A0]], -1
+; CHECK-NEXT:    [[AND:%.*]] = and i8 [[DEC]], [[NOT]]
+; CHECK-NEXT:    call void @use(i8 [[AND]])
+; CHECK-NEXT:    [[CLZ:%.*]] = tail call range(i8 0, 9) i8 @llvm.ctlz.i8(i8 [[AND]], i1 false)
+; CHECK-NEXT:    ret i8 [[CLZ]]
+;
+  %dec = add i8 %a0, -1
+  %not = xor i8 %a0, -1
+  %and = and i8 %dec, %not
+  call void @use(i8 %and)
+  %clz = tail call i8 @llvm.ctlz.i8(i8 %and, i1 false)
+  ret i8 %clz
+}
+
+define i8 @ctlz_to_sub_bw_cttz_commute_and(i8 %a0) {
+; CHECK-LABEL: define i8 @ctlz_to_sub_bw_cttz_commute_and(
+; CHECK-SAME: i8 [[A0:%.*]]) {
+; CHECK-NEXT:    [[TMP1:%.*]] = call range(i8 0, 9) i8 @llvm.cttz.i8(i8 [[A0]], i1 false)
+; CHECK-NEXT:    [[CLZ:%.*]] = sub nuw nsw i8 8, [[TMP1]]
+; CHECK-NEXT:    ret i8 [[CLZ]]
+;
+  %dec = add i8 %a0, -1
+  %not = xor i8 %a0, -1
+  %and = and i8 %not, %dec
+  %clz = tail call i8 @llvm.ctlz.i8(i8 %and, i1 false)
+  ret i8 %clz
+}
+
+define <2 x i8> @ctlz_to_sub_bw_cttz_vec_splat(<2 x i8> %a0) {
+; CHECK-LABEL: define <2 x i8> @ctlz_to_sub_bw_cttz_vec_splat(
+; CHECK-SAME: <2 x i8> [[A0:%.*]]) {
+; CHECK-NEXT:    [[TMP1:%.*]] = call range(i8 0, 9) <2 x i8> @llvm.cttz.v2i8(<2 x i8> [[A0]], i1 false)
+; CHECK-NEXT:    [[CLZ:%.*]] = sub nuw nsw <2 x i8> splat (i8 8), [[TMP1]]
+; CHECK-NEXT:    ret <2 x i8> [[CLZ]]
+;
+  %dec = add <2 x i8> %a0, <i8 -1, i8 -1>
+  %not = xor <2 x i8> %a0, <i8 -1, i8 -1>
+  %and = and <2 x i8> %dec, %not
+  %clz = tail call <2 x i8>@llvm.ctlz.v2i8(<2 x i8> %and, i1 false)
+  ret <2 x i8> %clz
+}