diff --git a/llvm/lib/Transforms/Utils/SCCPSolver.cpp b/llvm/lib/Transforms/Utils/SCCPSolver.cpp
index f4b378b82daec..32170e3705b81 100644
--- a/llvm/lib/Transforms/Utils/SCCPSolver.cpp
+++ b/llvm/lib/Transforms/Utils/SCCPSolver.cpp
@@ -19,7 +19,9 @@
 #include "llvm/Analysis/ValueLattice.h"
 #include "llvm/Analysis/ValueLatticeUtils.h"
 #include "llvm/Analysis/ValueTracking.h"
+#include "llvm/IR/IRBuilder.h"
 #include "llvm/IR/InstVisitor.h"
+#include "llvm/IR/NoFolder.h"
 #include "llvm/IR/PatternMatch.h"
 #include "llvm/Support/Casting.h"
 #include "llvm/Support/Debug.h"
@@ -245,11 +247,43 @@ static Value *simplifyInstruction(SCCPSolver &Solver,
   const APInt *RHSC;
   // Remove masking operations.
   if (match(&Inst, m_And(m_Value(X), m_LowBitMask(RHSC)))) {
-    ConstantRange LRange = GetRange(Inst.getOperand(0));
+    ConstantRange LRange = GetRange(X);
     if (LRange.getUnsignedMax().ule(*RHSC))
       return X;
   }
 
+  // Check if we can simplify [us]cmp(X, Y) to X - Y.
+  if (auto *Cmp = dyn_cast<CmpIntrinsic>(&Inst)) {
+    Value *LHS = Cmp->getOperand(0);
+    Value *RHS = Cmp->getOperand(1);
+    unsigned BitWidth = LHS->getType()->getScalarSizeInBits();
+    // Bail out on 1-bit comparisons.
+    if (BitWidth == 1)
+      return nullptr;
+    ConstantRange LRange = GetRange(LHS);
+    if (LRange.isSizeLargerThan(3))
+      return nullptr;
+    ConstantRange RRange = GetRange(RHS);
+    if (RRange.isSizeLargerThan(3))
+      return nullptr;
+    ConstantRange RHSLower = RRange.sub(APInt(BitWidth, 1));
+    ConstantRange RHSUpper = RRange.add(APInt(BitWidth, 1));
+    ICmpInst::Predicate Pred =
+        Cmp->isSigned() ? CmpInst::ICMP_SLE : CmpInst::ICMP_ULE;
+    if (!RHSLower.icmp(Pred, LRange) || !LRange.icmp(Pred, RHSUpper))
+      return nullptr;
+
+    IRBuilder<NoFolder> Builder(&Inst);
+    Value *Sub = Builder.CreateSub(LHS, RHS, Inst.getName(), /*HasNUW=*/false,
+                                   /*HasNSW=*/Cmp->isSigned());
+    InsertedValues.insert(Sub);
+    if (Sub->getType() != Inst.getType()) {
+      Sub = Builder.CreateSExtOrTrunc(Sub, Inst.getType());
+      InsertedValues.insert(Sub);
+    }
+    return Sub;
+  }
+
   return nullptr;
 }
 
diff --git a/llvm/test/Transforms/SCCP/uscmp.ll b/llvm/test/Transforms/SCCP/uscmp.ll
new file mode 100644
index 0000000000000..d010c0632c809
--- /dev/null
+++ b/llvm/test/Transforms/SCCP/uscmp.ll
@@ -0,0 +1,185 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
+; RUN: opt -passes=sccp -S < %s | FileCheck %s
+
+define i32 @scmp_to_sub(i32 range(i32 -1, 2) %a) {
+; CHECK-LABEL: define i32 @scmp_to_sub(
+; CHECK-SAME: i32 range(i32 -1, 2) [[A:%.*]]) {
+; CHECK-NEXT:    [[SCMP:%.*]] = sub nsw i32 [[A]], 0
+; CHECK-NEXT:    ret i32 [[SCMP]]
+;
+  %scmp = call i32 @llvm.scmp(i32 %a, i32 0)
+  ret i32 %scmp
+}
+
+define i32 @scmp_zext_to_sub(i1 %a, i1 %b) {
+; CHECK-LABEL: define i32 @scmp_zext_to_sub(
+; CHECK-SAME: i1 [[A:%.*]], i1 [[B:%.*]]) {
+; CHECK-NEXT:    [[ZEXT_A:%.*]] = zext i1 [[A]] to i32
+; CHECK-NEXT:    [[ZEXT_B:%.*]] = zext i1 [[B]] to i32
+; CHECK-NEXT:    [[SCMP:%.*]] = sub nsw i32 [[ZEXT_A]], [[ZEXT_B]]
+; CHECK-NEXT:    ret i32 [[SCMP]]
+;
+  %zext_a = zext i1 %a to i32
+  %zext_b = zext i1 %b to i32
+  %scmp = call i32 @llvm.scmp(i32 %zext_a, i32 %zext_b)
+  ret i32 %scmp
+}
+
+define i8 @scmp_to_sub_trunc(i32 range(i32 -1, 2) %a) {
+; CHECK-LABEL: define i8 @scmp_to_sub_trunc(
+; CHECK-SAME: i32 range(i32 -1, 2) [[A:%.*]]) {
+; CHECK-NEXT:    [[SCMP1:%.*]] = sub nsw i32 [[A]], 0
+; CHECK-NEXT:    [[SCMP:%.*]] = trunc i32 [[SCMP1]] to i8
+; CHECK-NEXT:    ret i8 [[SCMP]]
+;
+  %scmp = call i8 @llvm.scmp(i32 %a, i32 0)
+  ret i8 %scmp
+}
+
+define i64 @scmp_to_sub_sext(i32 range(i32 -1, 2) %a) {
+; CHECK-LABEL: define i64 @scmp_to_sub_sext(
+; CHECK-SAME: i32 range(i32 -1, 2) [[A:%.*]]) {
+; CHECK-NEXT:    [[SCMP1:%.*]] = sub nsw i32 [[A]], 0
+; CHECK-NEXT:    [[SCMP:%.*]] = sext i32 [[SCMP1]] to i64
+; CHECK-NEXT:    ret i64 [[SCMP]]
+;
+  %scmp = call i64 @llvm.scmp(i32 %a, i32 0)
+  ret i64 %scmp
+}
+
+define i32 @scmp_to_sub_small_range(i32 range(i32 -1, 1) %a) {
+; CHECK-LABEL: define i32 @scmp_to_sub_small_range(
+; CHECK-SAME: i32 range(i32 -1, 1) [[A:%.*]]) {
+; CHECK-NEXT:    [[SCMP:%.*]] = sub nsw i32 [[A]], 0
+; CHECK-NEXT:    ret i32 [[SCMP]]
+;
+  %scmp = call i32 @llvm.scmp(i32 %a, i32 0)
+  ret i32 %scmp
+}
+
+define i32 @ucmp_to_sub(i32 range(i32 0, 3) %a) {
+; CHECK-LABEL: define i32 @ucmp_to_sub(
+; CHECK-SAME: i32 range(i32 0, 3) [[A:%.*]]) {
+; CHECK-NEXT:    [[SCMP:%.*]] = sub i32 [[A]], 1
+; CHECK-NEXT:    ret i32 [[SCMP]]
+;
+  %ucmp = call i32 @llvm.ucmp(i32 %a, i32 1)
+  ret i32 %ucmp
+}
+
+define i8 @ucmp_to_sub_trunc(i32 range(i32 0, 3) %a) {
+; CHECK-LABEL: define i8 @ucmp_to_sub_trunc(
+; CHECK-SAME: i32 range(i32 0, 3) [[A:%.*]]) {
+; CHECK-NEXT:    [[UCMP1:%.*]] = sub i32 [[A]], 1
+; CHECK-NEXT:    [[UCMP:%.*]] = trunc i32 [[UCMP1]] to i8
+; CHECK-NEXT:    ret i8 [[UCMP]]
+;
+  %ucmp = call i8 @llvm.ucmp(i32 %a, i32 1)
+  ret i8 %ucmp
+}
+
+define i64 @ucmp_to_sub_sext(i32 range(i32 0, 3) %a) {
+; CHECK-LABEL: define i64 @ucmp_to_sub_sext(
+; CHECK-SAME: i32 range(i32 0, 3) [[A:%.*]]) {
+; CHECK-NEXT:    [[UCMP1:%.*]] = sub i32 [[A]], 1
+; CHECK-NEXT:    [[UCMP:%.*]] = sext i32 [[UCMP1]] to i64
+; CHECK-NEXT:    ret i64 [[UCMP]]
+;
+  %ucmp = call i64 @llvm.ucmp(i32 %a, i32 1)
+  ret i64 %ucmp
+}
+
+; TODO: we can fold this into %a.
+define i32 @ucmp_to_sub_small_range(i32 range(i32 0, 2) %a) {
+; CHECK-LABEL: define i32 @ucmp_to_sub_small_range(
+; CHECK-SAME: i32 range(i32 0, 2) [[A:%.*]]) {
+; CHECK-NEXT:    [[UCMP:%.*]] = call i32 @llvm.ucmp.i32.i32(i32 [[A]], i32 0)
+; CHECK-NEXT:    ret i32 [[UCMP]]
+;
+  %ucmp = call i32 @llvm.ucmp(i32 %a, i32 0)
+  ret i32 %ucmp
+}
+
+define i32 @scmp_to_sub_large_range(i32 range(i32 -1, 3) %a) {
+; CHECK-LABEL: define i32 @scmp_to_sub_large_range(
+; CHECK-SAME: i32 range(i32 -1, 3) [[A:%.*]]) {
+; CHECK-NEXT:    [[SCMP:%.*]] = call i32 @llvm.scmp.i32.i32(i32 [[A]], i32 0)
+; CHECK-NEXT:    ret i32 [[SCMP]]
+;
+  %scmp = call i32 @llvm.scmp(i32 %a, i32 0)
+  ret i32 %scmp
+}
+
+define i32 @ucmp_to_sub_large_range(i32 range(i32 -1, 3) %a) {
+; CHECK-LABEL: define i32 @ucmp_to_sub_large_range(
+; CHECK-SAME: i32 range(i32 -1, 3) [[A:%.*]]) {
+; CHECK-NEXT:    [[SCMP:%.*]] = call i32 @llvm.ucmp.i32.i32(i32 [[A]], i32 0)
+; CHECK-NEXT:    ret i32 [[SCMP]]
+;
+  %ucmp = call i32 @llvm.ucmp(i32 %a, i32 0)
+  ret i32 %ucmp
+}
+
+define i32 @scmp_to_sub_wrap(i8 range(i8 127, -126) %a) {
+; CHECK-LABEL: define i32 @scmp_to_sub_wrap(
+; CHECK-SAME: i8 range(i8 127, -126) [[A:%.*]]) {
+; CHECK-NEXT:    [[SCMP:%.*]] = call i32 @llvm.scmp.i32.i8(i8 [[A]], i8 -128)
+; CHECK-NEXT:    ret i32 [[SCMP]]
+;
+  %scmp = call i32 @llvm.scmp(i8 %a, i8 -128)
+  ret i32 %scmp
+}
+
+define i32 @ucmp_to_sub_wrap(i8 range(i8 -1, 2) %a) {
+; CHECK-LABEL: define i32 @ucmp_to_sub_wrap(
+; CHECK-SAME: i8 range(i8 -1, 2) [[A:%.*]]) {
+; CHECK-NEXT:    [[UCMP:%.*]] = call i32 @llvm.ucmp.i32.i8(i8 [[A]], i8 0)
+; CHECK-NEXT:    ret i32 [[UCMP]]
+;
+  %ucmp = call i32 @llvm.ucmp(i8 %a, i8 0)
+  ret i32 %ucmp
+}
+
+; It is incorrect to convert a ucmp into sub when the input type is i1.
+define i32 @ucmp_to_sub_i1_rhs_const(i1 %a) {
+; CHECK-LABEL: define i32 @ucmp_to_sub_i1_rhs_const(
+; CHECK-SAME: i1 [[A:%.*]]) {
+; CHECK-NEXT:    [[SCMP:%.*]] = call i32 @llvm.ucmp.i32.i1(i1 [[A]], i1 false)
+; CHECK-NEXT:    ret i32 [[SCMP]]
+;
+  %ucmp = call i32 @llvm.ucmp(i1 %a, i1 false)
+  ret i32 %ucmp
+}
+
+; It is incorrect to convert a ucmp into sub when the input type is i1.
+define i32 @ucmp_to_sub_i1_lhs_const(i1 %a) {
+; CHECK-LABEL: define i32 @ucmp_to_sub_i1_lhs_const(
+; CHECK-SAME: i1 [[A:%.*]]) {
+; CHECK-NEXT:    [[SCMP:%.*]] = call i32 @llvm.ucmp.i32.i1(i1 false, i1 [[A]])
+; CHECK-NEXT:    ret i32 [[SCMP]]
+;
+  %ucmp = call i32 @llvm.ucmp(i1 false, i1 %a)
+  ret i32 %ucmp
+}
+
+; It is incorrect to convert a ucmp into sub when the input type is i1.
+define i32 @ucmp_to_sub_i1(i1 %a, i1 %b) {
+; CHECK-LABEL: define i32 @ucmp_to_sub_i1(
+; CHECK-SAME: i1 [[A:%.*]], i1 [[B:%.*]]) {
+; CHECK-NEXT:    [[SCMP:%.*]] = call i32 @llvm.ucmp.i32.i1(i1 [[A]], i1 [[B]])
+; CHECK-NEXT:    ret i32 [[SCMP]]
+;
+  %ucmp = call i32 @llvm.ucmp(i1 %a, i1 %b)
+  ret i32 %ucmp
+}
+
+; It is incorrect to convert a scmp into sub when the input type is i1.
+define i32 @scmp_to_sub_i1_rhs_const(i1 %a) {
+; CHECK-LABEL: define i32 @scmp_to_sub_i1_rhs_const(
+; CHECK-SAME: i1 [[A:%.*]]) {
+; CHECK-NEXT:    [[SCMP:%.*]] = call i32 @llvm.scmp.i32.i1(i1 [[A]], i1 false)
+; CHECK-NEXT:    ret i32 [[SCMP]]
+;
+  %scmp = call i32 @llvm.scmp(i1 %a, i1 false)
+  ret i32 %scmp
+}