diff --git a/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp b/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
index 73ba0f78e8053..a615505fd4f73 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
@@ -3635,6 +3635,10 @@ static Instruction *foldBitCeil(SelectInst &SI, IRBuilderBase &Builder,
 //   (x < y) ? -1 : zext(x > y)
 //   (x > y) ? 1 : sext(x != y)
 //   (x > y) ? 1 : sext(x < y)
+//   (x == y) ? 0 : (x > y ? 1 : -1)
+//   (x == y) ? 0 : (x < y ? -1 : 1)
+//   Special case: x == C ? 0 : (x > C - 1 ? 1 : -1)
+//   Special case: x == C ? 0 : (x < C + 1 ? -1 : 1)
 // Into ucmp/scmp(x, y), where signedness is determined by the signedness
 // of the comparison in the original sequence.
 Instruction *InstCombinerImpl::foldSelectToCmp(SelectInst &SI) {
@@ -3727,6 +3731,45 @@ Instruction *InstCombinerImpl::foldSelectToCmp(SelectInst &SI) {
     }
   }
 
+  // Special cases with constants: x == C ? 0 : (x > C-1 ? 1 : -1)
+  if (Pred == ICmpInst::ICMP_EQ && match(TV, m_Zero())) {
+    Value *X;
+    const APInt *C;
+    if (match(LHS, m_Value(X)) && match(RHS, m_APInt(C))) {
+      CmpPredicate InnerPred;
+      Value *InnerLHS, *InnerRHS;
+      const APInt *InnerTV, *InnerFV;
+      if (match(FV, m_Select(
+                        m_ICmp(InnerPred, m_Value(InnerLHS), m_Value(InnerRHS)),
+                        m_APInt(InnerTV), m_APInt(InnerFV)))) {
+
+        // x == C ? 0 : (x > C-1 ? 1 : -1)
+        if (ICmpInst::isGT(InnerPred) && InnerTV->isOne() &&
+            InnerFV->isAllOnes()) {
+          IsSigned = ICmpInst::isSigned(InnerPred);
+          bool CanSubOne = IsSigned ? !C->isMinSignedValue() : !C->isMinValue();
+          if (CanSubOne) {
+            APInt Cminus1 = *C - 1;
+            if (InnerLHS == X && match(InnerRHS, m_SpecificInt(Cminus1)))
+              Replace = true;
+          }
+        }
+
+        // x == C ? 0 : (x < C+1 ? -1 : 1)
+        if (ICmpInst::isLT(InnerPred) && InnerTV->isAllOnes() &&
+            InnerFV->isOne()) {
+          IsSigned = ICmpInst::isSigned(InnerPred);
+          bool CanAddOne = IsSigned ? !C->isMaxSignedValue() : !C->isMaxValue();
+          if (CanAddOne) {
+            APInt Cplus1 = *C + 1;
+            if (InnerLHS == X && match(InnerRHS, m_SpecificInt(Cplus1)))
+              Replace = true;
+          }
+        }
+      }
+    }
+  }
+
   Intrinsic::ID IID = IsSigned ? Intrinsic::scmp : Intrinsic::ucmp;
   if (Replace)
     return replaceInstUsesWith(
@@ -4496,5 +4539,20 @@ Instruction *InstCombinerImpl::visitSelectInst(SelectInst &SI) {
       return replaceOperand(SI, 2, ConstantInt::get(FalseVal->getType(), 0));
   }
 
+  // Canonicalize sign function ashr pattern: select (icmp slt X, 1), ashr X,
+  // bitwidth-1, 1 -> scmp(X, 0)
+  Value *X;
+  unsigned BitWidth = SI.getType()->getScalarSizeInBits();
+  CmpPredicate Pred;
+  if (match(&SI, m_Select(m_ICmp(Pred, m_Value(X), m_One()),
+                          m_AShr(m_Deferred(X), m_SpecificInt(BitWidth - 1)),
+                          m_One())) &&
+      Pred == ICmpInst::ICMP_SLT) {
+
+    Function *Scmp = Intrinsic::getOrInsertDeclaration(
+        SI.getModule(), Intrinsic::scmp, {SI.getType(), SI.getType()});
+    return CallInst::Create(Scmp, {X, ConstantInt::get(SI.getType(), 0)});
+  }
+
   return nullptr;
 }
diff --git a/llvm/test/Transforms/InstCombine/scmp.ll b/llvm/test/Transforms/InstCombine/scmp.ll
index 2bf22aeb7a6e9..972965eaa6fc2 100644
--- a/llvm/test/Transforms/InstCombine/scmp.ll
+++ b/llvm/test/Transforms/InstCombine/scmp.ll
@@ -436,6 +436,197 @@ define <3 x i2> @scmp_unary_shuffle_ops(<3 x i8> %x, <3 x i8> %y) {
   ret <3 x i2> %r
 }
 
+define i32 @scmp_ashr(i32 %a) {
+; CHECK-LABEL: define i32 @scmp_ashr(
+; CHECK-SAME: i32 [[A:%.*]]) {
+; CHECK-NEXT:    [[RETVAL_0:%.*]] = call i32 @llvm.scmp.i32.i32(i32 [[A]], i32 0)
+; CHECK-NEXT:    ret i32 [[RETVAL_0]]
+;
+  %a.lobit = ashr i32 %a, 31
+  %cmp.inv = icmp slt i32 %a, 1
+  %retval.0 = select i1 %cmp.inv, i32 %a.lobit, i32 1
+  ret i32 %retval.0
+}
+
+define i32 @scmp_sgt_slt(i32 %a) {
+; CHECK-LABEL: define i32 @scmp_sgt_slt(
+; CHECK-SAME: i32 [[A:%.*]]) {
+; CHECK-NEXT:    [[RETVAL_0:%.*]] = call i32 @llvm.scmp.i32.i32(i32 [[A]], i32 0)
+; CHECK-NEXT:    ret i32 [[RETVAL_0]]
+;
+  %cmp = icmp sgt i32 %a, 0
+  %cmp1 = icmp slt i32 %a, 0
+  %. = select i1 %cmp1, i32 -1, i32 0
+  %retval.0 = select i1 %cmp, i32 1, i32 %.
+  ret i32 %retval.0
+}
+
+define i32 @scmp_zero_slt(i32 %a) {
+; CHECK-LABEL: define i32 @scmp_zero_slt(
+; CHECK-SAME: i32 [[A:%.*]]) {
+; CHECK-NEXT:    [[RETVAL_0:%.*]] = call i32 @llvm.scmp.i32.i32(i32 [[A]], i32 0)
+; CHECK-NEXT:    ret i32 [[RETVAL_0]]
+;
+  %cmp = icmp eq i32 %a, 0
+  %cmp1.inv = icmp slt i32 %a, 1
+  %. = select i1 %cmp1.inv, i32 -1, i32 1
+  %retval.0 = select i1 %cmp, i32 0, i32 %.
+  ret i32 %retval.0
+}
+
+define i32 @scmp_zero_sgt(i32 %a) {
+; CHECK-LABEL: define i32 @scmp_zero_sgt(
+; CHECK-SAME: i32 [[A:%.*]]) {
+; CHECK-NEXT:    [[RETVAL_0:%.*]] = call i32 @llvm.scmp.i32.i32(i32 [[A]], i32 0)
+; CHECK-NEXT:    ret i32 [[RETVAL_0]]
+;
+  %cmp = icmp eq i32 %a, 0
+  %cmp1.inv = icmp sgt i32 %a, -1
+  %. = select i1 %cmp1.inv, i32 1, i32 -1
+  %retval.0 = select i1 %cmp, i32 0, i32 %.
+  ret i32 %retval.0
+}
+
+
+define i32 @scmp_zero_sgt_1(i32 %a) {
+; CHECK-LABEL: define i32 @scmp_zero_sgt_1(
+; CHECK-SAME: i32 [[A:%.*]]) {
+; CHECK-NEXT:    [[COND2:%.*]] = call i32 @llvm.scmp.i32.i32(i32 [[A]], i32 0)
+; CHECK-NEXT:    ret i32 [[COND2]]
+;
+  %cmp = icmp eq i32 %a, 0
+  %cmp1 = icmp sgt i32 %a, -1
+  %cond = select i1 %cmp1, i32 1, i32 -1
+  %cond2 = select i1 %cmp, i32 0, i32 %cond
+  ret i32 %cond2
+}
+
+define i32 @scmp_zero_slt_1(i32 %a) {
+; CHECK-LABEL: define i32 @scmp_zero_slt_1(
+; CHECK-SAME: i32 [[A:%.*]]) {
+; CHECK-NEXT:    [[COND2:%.*]] = call i32 @llvm.scmp.i32.i32(i32 [[A]], i32 0)
+; CHECK-NEXT:    ret i32 [[COND2]]
+;
+  %cmp = icmp eq i32 %a, 0
+  %cmp1 = icmp slt i32 %a, 1
+  %cond = select i1 %cmp1, i32 -1, i32 1
+  %cond2 = select i1 %cmp, i32 0, i32 %cond
+  ret i32 %cond2
+}
+
+define i32 @scmp_zero_slt_neg(i32 %a) {
+; CHECK-LABEL: define i32 @scmp_zero_slt_neg(
+; CHECK-SAME: i32 [[A:%.*]]) {
+; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i32 [[A]], 0
+; CHECK-NEXT:    [[CMP1:%.*]] = icmp slt i32 [[A]], -1
+; CHECK-NEXT:    [[COND:%.*]] = select i1 [[CMP1]], i32 -1, i32 1
+; CHECK-NEXT:    [[COND2:%.*]] = select i1 [[CMP]], i32 0, i32 [[COND]]
+; CHECK-NEXT:    ret i32 [[COND2]]
+;
+  %cmp = icmp eq i32 %a, 0
+  %cmp1 = icmp slt i32 %a, -1
+  %cond = select i1 %cmp1, i32 -1, i32 1
+  %cond2 = select i1 %cmp, i32 0, i32 %cond
+  ret i32 %cond2
+}
+
+define i32 @scmp_zero_sgt_neg(i32 %a) {
+; CHECK-LABEL: define i32 @scmp_zero_sgt_neg(
+; CHECK-SAME: i32 [[A:%.*]]) {
+; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i32 [[A]], 0
+; CHECK-NEXT:    [[CMP1:%.*]] = icmp sgt i32 [[A]], 1
+; CHECK-NEXT:    [[COND:%.*]] = select i1 [[CMP1]], i32 1, i32 -1
+; CHECK-NEXT:    [[COND2:%.*]] = select i1 [[CMP]], i32 0, i32 [[COND]]
+; CHECK-NEXT:    ret i32 [[COND2]]
+;
+  %cmp = icmp eq i32 %a, 0
+  %cmp1 = icmp sgt i32 %a, 1
+  %cond = select i1 %cmp1, i32 1, i32 -1
+  %cond2 = select i1 %cmp, i32 0, i32 %cond
+  ret i32 %cond2
+}
+
+define i32 @ucmp_ugt_ult_neg(i32 %a) {
+; CHECK-LABEL: define i32 @ucmp_ugt_ult_neg(
+; CHECK-SAME: i32 [[A:%.*]]) {
+; CHECK-NEXT:    [[CMP_NOT:%.*]] = icmp ne i32 [[A]], 0
+; CHECK-NEXT:    [[RETVAL_0:%.*]] = zext i1 [[CMP_NOT]] to i32
+; CHECK-NEXT:    ret i32 [[RETVAL_0]]
+;
+  %cmp = icmp ugt i32 %a, 0
+  %cmp1 = icmp ult i32 %a, 0
+  %. = select i1 %cmp1, i32 -1, i32 0
+  %retval.0 = select i1 %cmp, i32 1, i32 %.
+  ret i32 %retval.0
+}
+
+define i32 @ucmp_zero_ult_neg(i32 %a) {
+; CHECK-LABEL: define i32 @ucmp_zero_ult_neg(
+; CHECK-SAME: i32 [[A:%.*]]) {
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ne i32 [[A]], 0
+; CHECK-NEXT:    [[RETVAL_0:%.*]] = zext i1 [[CMP]] to i32
+; CHECK-NEXT:    ret i32 [[RETVAL_0]]
+;
+  %cmp = icmp eq i32 %a, 0
+  %cmp1.inv = icmp ult i32 %a, 1
+  %. = select i1 %cmp1.inv, i32 -1, i32 1
+  %retval.0 = select i1 %cmp, i32 0, i32 %.
+  ret i32 %retval.0
+}
+
+define i32 @ucmp_zero_ugt_neg(i32 %a) {
+; CHECK-LABEL: define i32 @ucmp_zero_ugt_neg(
+; CHECK-SAME: i32 [[A:%.*]]) {
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ne i32 [[A]], 0
+; CHECK-NEXT:    [[RETVAL_0:%.*]] = sext i1 [[CMP]] to i32
+; CHECK-NEXT:    ret i32 [[RETVAL_0]]
+;
+  %cmp = icmp eq i32 %a, 0
+  %cmp1.inv = icmp ugt i32 %a, -1
+  %. = select i1 %cmp1.inv, i32 1, i32 -1
+  %retval.0 = select i1 %cmp, i32 0, i32 %.
+  ret i32 %retval.0
+}
+
+define i32 @scmp_sgt_slt_ab(i32 %a, i32 %b) {
+; CHECK-LABEL: define i32 @scmp_sgt_slt_ab(
+; CHECK-SAME: i32 [[A:%.*]], i32 [[B:%.*]]) {
+; CHECK-NEXT:    [[RETVAL_0:%.*]] = call i32 @llvm.scmp.i32.i32(i32 [[A]], i32 [[B]])
+; CHECK-NEXT:    ret i32 [[RETVAL_0]]
+;
+  %cmp = icmp sgt i32 %a, %b
+  %cmp1 = icmp slt i32 %a, %b
+  %. = select i1 %cmp1, i32 -1, i32 0
+  %retval.0 = select i1 %cmp, i32 1, i32 %.
+  ret i32 %retval.0
+}
+
+define i32 @scmp_zero_slt_ab(i32 %a, i32 %b) {
+; CHECK-LABEL: define i32 @scmp_zero_slt_ab(
+; CHECK-SAME: i32 [[A:%.*]], i32 [[B:%.*]]) {
+; CHECK-NEXT:    [[RETVAL_0:%.*]] = call i32 @llvm.scmp.i32.i32(i32 [[A]], i32 [[B]])
+; CHECK-NEXT:    ret i32 [[RETVAL_0]]
+;
+  %cmp = icmp eq i32 %a, %b
+  %cmp1.inv = icmp slt i32 %a, %b
+  %. = select i1 %cmp1.inv, i32 -1, i32 1
+  %retval.0 = select i1 %cmp, i32 0, i32 %.
+  ret i32 %retval.0
+}
+
+define i32 @scmp_zero_sgt_ab(i32 %a, i32 %b) {
+; CHECK-LABEL: define i32 @scmp_zero_sgt_ab(
+; CHECK-SAME: i32 [[A:%.*]], i32 [[B:%.*]]) {
+; CHECK-NEXT:    [[RETVAL_0:%.*]] = call i32 @llvm.scmp.i32.i32(i32 [[A]], i32 [[B]])
+; CHECK-NEXT:    ret i32 [[RETVAL_0]]
+;
+  %cmp = icmp eq i32 %a, %b
+  %cmp1.inv = icmp sgt i32 %a, %b
+  %. = select i1 %cmp1.inv, i32 1, i32 -1
+  %retval.0 = select i1 %cmp, i32 0, i32 %.
+  ret i32 %retval.0
+}
+
 ; Negative test: true value of outer select is not zero
 define i8 @scmp_from_select_eq_and_gt_neg1(i32 %x, i32 %y) {
 ; CHECK-LABEL: define i8 @scmp_from_select_eq_and_gt_neg1(