Index: llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
===================================================================
--- llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
+++ llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
@@ -5830,6 +5830,42 @@
       Y->getType()->isIntOrIntVectorTy(1) && Pred == ICmpInst::ICMP_ULE)
     return BinaryOperator::CreateOr(Builder.CreateIsNull(X), Y);
 
+  const APInt *CmpC;
+  // For the pattern: (zext i1 X) + (sext i1 Y)), C
+  // when C == -1 means, X == false ,Y == true
+  // C == 0 means , X == Y
+  // C == 1 means, X == true, Y == false
+  // So based on these info we can simplify the icmp
+  if (match(I.getOperand(0),
+            m_OneUse(m_c_Add(m_ZExt(m_Value(X)), m_SExt(m_Value(Y))))) &&
+      match(I.getOperand(1), m_APInt(CmpC)) &&
+      X->getType()->isIntOrIntVectorTy(1) &&
+      Y->getType()->isIntOrIntVectorTy(1) && CmpC->abs().ule(1)) {
+    Pred = I.getPredicate();
+    switch (CmpC->getSExtValue()) {
+    case -1:
+      if (Pred == ICmpInst::ICMP_EQ)
+        return BinaryOperator::CreateAnd(Builder.CreateNot(X), Y);
+      if (Pred == ICmpInst::ICMP_NE || Pred == ICmpInst::ICMP_SGT)
+        return BinaryOperator::CreateOr(X, Builder.CreateNot(Y));
+      break;
+    case 0:
+      if (Pred == ICmpInst::ICMP_SGT)
+        return BinaryOperator::CreateAnd(X, Builder.CreateNot(Y));
+      if (Pred == ICmpInst::ICMP_SLT)
+        return BinaryOperator::CreateAnd(Builder.CreateNot(X), Y);
+      break;
+    case 1:
+      if (Pred == ICmpInst::ICMP_EQ)
+        return BinaryOperator::CreateAnd(X, Builder.CreateNot(Y));
+      if (Pred == ICmpInst::ICMP_NE || Pred == ICmpInst::ICMP_SLT)
+        return BinaryOperator::CreateOr(Builder.CreateNot(X), Y);
+      break;
+    default:
+      llvm_unreachable("CmpC should be also one of [-1, 0, 1]");
+    }
+  }
+
   return nullptr;
 }
 
Index: llvm/test/Transforms/InstCombine/icmp-range.ll
===================================================================
--- llvm/test/Transforms/InstCombine/icmp-range.ll
+++ llvm/test/Transforms/InstCombine/icmp-range.ll
@@ -631,10 +631,8 @@
 
 define i1 @zext_sext_add_icmp_eq_minus1(i1 %a, i1 %b) {
 ; CHECK-LABEL: @zext_sext_add_icmp_eq_minus1(
-; CHECK-NEXT:    [[ZEXT_A:%.*]] = zext i1 [[A:%.*]] to i8
-; CHECK-NEXT:    [[ZEXT_B:%.*]] = sext i1 [[B:%.*]] to i8
-; CHECK-NEXT:    [[ADD:%.*]] = add nsw i8 [[ZEXT_A]], [[ZEXT_B]]
-; CHECK-NEXT:    [[R:%.*]] = icmp eq i8 [[ADD]], -1
+; CHECK-NEXT:    [[TMP1:%.*]] = xor i1 [[A:%.*]], true
+; CHECK-NEXT:    [[R:%.*]] = and i1 [[TMP1]], [[B:%.*]]
 ; CHECK-NEXT:    ret i1 [[R]]
 ;
   %zext.a = zext i1 %a to i8
@@ -646,10 +644,8 @@
 
 define i1 @zext_sext_add_icmp_ne_minus1(i1 %a, i1 %b) {
 ; CHECK-LABEL: @zext_sext_add_icmp_ne_minus1(
-; CHECK-NEXT:    [[ZEXT_A:%.*]] = zext i1 [[A:%.*]] to i8
-; CHECK-NEXT:    [[ZEXT_B:%.*]] = sext i1 [[B:%.*]] to i8
-; CHECK-NEXT:    [[ADD:%.*]] = add nsw i8 [[ZEXT_A]], [[ZEXT_B]]
-; CHECK-NEXT:    [[R:%.*]] = icmp ne i8 [[ADD]], -1
+; CHECK-NEXT:    [[TMP1:%.*]] = xor i1 [[B:%.*]], true
+; CHECK-NEXT:    [[R:%.*]] = or i1 [[TMP1]], [[A:%.*]]
 ; CHECK-NEXT:    ret i1 [[R]]
 ;
   %zext.a = zext i1 %a to i8
@@ -661,8 +657,8 @@
 
 define i1 @zext_sext_add_icmp_sgt_minus1(i1 %a, i1 %b) {
 ; CHECK-LABEL: @zext_sext_add_icmp_sgt_minus1(
-; CHECK-NEXT:    [[B_NOT:%.*]] = xor i1 [[B:%.*]], true
-; CHECK-NEXT:    [[R:%.*]] = or i1 [[B_NOT]], [[A:%.*]]
+; CHECK-NEXT:    [[TMP1:%.*]] = xor i1 [[B:%.*]], true
+; CHECK-NEXT:    [[R:%.*]] = or i1 [[TMP1]], [[A:%.*]]
 ; CHECK-NEXT:    ret i1 [[R]]
 ;
   %zext.a = zext i1 %a to i8
@@ -674,10 +670,8 @@
 
 define i1 @zext_sext_add_icmp_sgt_0(i1 %a, i1 %b) {
 ; CHECK-LABEL: @zext_sext_add_icmp_sgt_0(
-; CHECK-NEXT:    [[ZEXT_A:%.*]] = zext i1 [[A:%.*]] to i8
-; CHECK-NEXT:    [[ZEXT_B:%.*]] = sext i1 [[B:%.*]] to i8
-; CHECK-NEXT:    [[ADD:%.*]] = add nsw i8 [[ZEXT_A]], [[ZEXT_B]]
-; CHECK-NEXT:    [[R:%.*]] = icmp sgt i8 [[ADD]], 0
+; CHECK-NEXT:    [[TMP1:%.*]] = xor i1 [[B:%.*]], true
+; CHECK-NEXT:    [[R:%.*]] = and i1 [[TMP1]], [[A:%.*]]
 ; CHECK-NEXT:    ret i1 [[R]]
 ;
   %zext.a = zext i1 %a to i8
@@ -690,8 +684,8 @@
 define i1 @zext_sext_add_icmp_slt_0(i1 %a, i1 %b) {
 ; CHECK-LABEL: @zext_sext_add_icmp_slt_0(
 ; CHECK-NEXT:    [[TMP1:%.*]] = xor i1 [[A:%.*]], true
-; CHECK-NEXT:    [[TMP2:%.*]] = and i1 [[TMP1]], [[B:%.*]]
-; CHECK-NEXT:    ret i1 [[TMP2]]
+; CHECK-NEXT:    [[R:%.*]] = and i1 [[TMP1]], [[B:%.*]]
+; CHECK-NEXT:    ret i1 [[R]]
 ;
   %zext.a = zext i1 %a to i8
   %zext.b = sext i1 %b to i8
@@ -702,10 +696,8 @@
 
 define i1 @zext_sext_add_icmp_eq_1(i1 %a, i1 %b) {
 ; CHECK-LABEL: @zext_sext_add_icmp_eq_1(
-; CHECK-NEXT:    [[ZEXT_A:%.*]] = zext i1 [[A:%.*]] to i8
-; CHECK-NEXT:    [[ZEXT_B:%.*]] = sext i1 [[B:%.*]] to i8
-; CHECK-NEXT:    [[ADD:%.*]] = add nsw i8 [[ZEXT_A]], [[ZEXT_B]]
-; CHECK-NEXT:    [[R:%.*]] = icmp eq i8 [[ADD]], 1
+; CHECK-NEXT:    [[TMP1:%.*]] = xor i1 [[B:%.*]], true
+; CHECK-NEXT:    [[R:%.*]] = and i1 [[TMP1]], [[A:%.*]]
 ; CHECK-NEXT:    ret i1 [[R]]
 ;
   %zext.a = zext i1 %a to i8
@@ -717,10 +709,8 @@
 
 define i1 @zext_sext_add_icmp_ne_1(i1 %a, i1 %b) {
 ; CHECK-LABEL: @zext_sext_add_icmp_ne_1(
-; CHECK-NEXT:    [[ZEXT_A:%.*]] = zext i1 [[A:%.*]] to i8
-; CHECK-NEXT:    [[ZEXT_B:%.*]] = sext i1 [[B:%.*]] to i8
-; CHECK-NEXT:    [[ADD:%.*]] = add nsw i8 [[ZEXT_A]], [[ZEXT_B]]
-; CHECK-NEXT:    [[R:%.*]] = icmp ne i8 [[ADD]], 1
+; CHECK-NEXT:    [[TMP1:%.*]] = xor i1 [[A:%.*]], true
+; CHECK-NEXT:    [[R:%.*]] = or i1 [[TMP1]], [[B:%.*]]
 ; CHECK-NEXT:    ret i1 [[R]]
 ;
   %zext.a = zext i1 %a to i8
@@ -732,10 +722,8 @@
 
 define i1 @zext_sext_add_icmp_slt_1(i1 %a, i1 %b) {
 ; CHECK-LABEL: @zext_sext_add_icmp_slt_1(
-; CHECK-NEXT:    [[ZEXT_A:%.*]] = zext i1 [[A:%.*]] to i8
-; CHECK-NEXT:    [[ZEXT_B:%.*]] = sext i1 [[B:%.*]] to i8
-; CHECK-NEXT:    [[ADD:%.*]] = add nsw i8 [[ZEXT_A]], [[ZEXT_B]]
-; CHECK-NEXT:    [[R:%.*]] = icmp slt i8 [[ADD]], 1
+; CHECK-NEXT:    [[TMP1:%.*]] = xor i1 [[A:%.*]], true
+; CHECK-NEXT:    [[R:%.*]] = or i1 [[TMP1]], [[B:%.*]]
 ; CHECK-NEXT:    ret i1 [[R]]
 ;
   %zext.a = zext i1 %a to i8
@@ -747,10 +735,8 @@
 
 define <2 x i1> @vector_zext_sext_add_icmp_slt_1(<2 x i1> %a, <2 x i1> %b) {
 ; CHECK-LABEL: @vector_zext_sext_add_icmp_slt_1(
-; CHECK-NEXT:    [[ZEXT_A:%.*]] = zext <2 x i1> [[A:%.*]] to <2 x i8>
-; CHECK-NEXT:    [[ZEXT_B:%.*]] = sext <2 x i1> [[B:%.*]] to <2 x i8>
-; CHECK-NEXT:    [[ADD:%.*]] = add nsw <2 x i8> [[ZEXT_A]], [[ZEXT_B]]
-; CHECK-NEXT:    [[R:%.*]] = icmp slt <2 x i8> [[ADD]], <i8 1, i8 1>
+; CHECK-NEXT:    [[TMP1:%.*]] = xor <2 x i1> [[A:%.*]], <i1 true, i1 true>
+; CHECK-NEXT:    [[R:%.*]] = or <2 x i1> [[TMP1]], [[B:%.*]]
 ; CHECK-NEXT:    ret <2 x i1> [[R]]
 ;
   %zext.a = zext <2 x i1> %a to <2 x i8>
@@ -775,6 +761,8 @@
   ret <2 x i1> %r
 }
 
+; Negative test, more than one use for icmp LHS
+
 define i1 @zext_sext_add_icmp_slt_1_no_oneuse(i1 %a, i1 %b) {
 ; CHECK-LABEL: @zext_sext_add_icmp_slt_1_no_oneuse(
 ; CHECK-NEXT:    [[ZEXT_A:%.*]] = zext i1 [[A:%.*]] to i8
@@ -792,6 +780,8 @@
   ret i1 %r
 }
 
+; Negative test, icmp RHS is not a constant
+
 define i1 @zext_sext_add_icmp_slt_1_rhs_not_const(i1 %a, i1 %b, i8 %c) {
 ; CHECK-LABEL: @zext_sext_add_icmp_slt_1_rhs_not_const(
 ; CHECK-NEXT:    [[ZEXT_A:%.*]] = zext i1 [[A:%.*]] to i8
@@ -807,6 +797,8 @@
   ret i1 %r
 }
 
+; Negative test, ext source is not i1
+
 define i1 @zext_sext_add_icmp_slt_1_type_not_i1(i2 %a, i1 %b) {
 ; CHECK-LABEL: @zext_sext_add_icmp_slt_1_type_not_i1(
 ; CHECK-NEXT:    [[ZEXT_A:%.*]] = zext i2 [[A:%.*]] to i8