Index: llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
===================================================================
--- llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
+++ llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
@@ -2524,6 +2524,34 @@
     }
   }
 
+  // sext(X + Y) - sext(X + Z) -> sext(Y) - sext(Z)
+  if ((match(Op0, m_SExt(m_NSWAdd(m_Value(X), m_Value(Y)))) &&
+       match(Op1, m_SExt(m_c_Add(m_Specific(X), m_Value(Z))))) ||
+      (match(Op0, m_SExt(m_NSWAdd(m_Value(Y), m_Value(X)))) &&
+       match(Op1, m_SExt(m_c_Add(m_Specific(X), m_Value(Z)))))) {
+    Value *Add1 = cast<Instruction>(Op1)->getOperand(0);
+    if ((Op0->hasOneUse() || Op1->hasOneUse() ||
+         (isa<Constant>(Y) && isa<Constant>(Z))) &&
+        cast<OverflowingBinaryOperator>(Add1)->hasNoSignedWrap()) {
+      Value *S1 = Builder.CreateSExt(Y, Ty);
+      Value *S2 = Builder.CreateSExt(Z, Ty);
+      return BinaryOperator::CreateSub(S1, S2);
+    }
+  }
+  if ((match(Op0, m_ZExt(m_NUWAdd(m_Value(X), m_Value(Y)))) &&
+       match(Op1, m_ZExt(m_c_Add(m_Specific(X), m_Value(Z))))) ||
+      (match(Op0, m_ZExt(m_NUWAdd(m_Value(Y), m_Value(X)))) &&
+       match(Op1, m_ZExt(m_c_Add(m_Specific(X), m_Value(Z)))))) {
+    Value *Add1 = cast<Instruction>(Op1)->getOperand(0);
+    if ((Op0->hasOneUse() || Op1->hasOneUse() ||
+         (isa<Constant>(Y) && isa<Constant>(Z))) &&
+        cast<OverflowingBinaryOperator>(Add1)->hasNoUnsignedWrap()) {
+      Value *S1 = Builder.CreateZExt(Y, Ty);
+      Value *S2 = Builder.CreateZExt(Z, Ty);
+      return BinaryOperator::CreateSub(S1, S2);
+    }
+  }
+
   if (Instruction *Res = foldBinOpOfSelectAndCastOfSelectCondition(I))
     return Res;
 
Index: llvm/test/Transforms/InstCombine/sub-ext-add.ll
===================================================================
--- llvm/test/Transforms/InstCombine/sub-ext-add.ll
+++ llvm/test/Transforms/InstCombine/sub-ext-add.ll
@@ -3,11 +3,9 @@
 
 define i32 @subaddnuw(i8 %a, i8 %C1, i8 %C2) {
 ; CHECK-LABEL: @subaddnuw(
-; CHECK-NEXT:    [[A1:%.*]] = add nuw i8 [[A:%.*]], [[C1:%.*]]
-; CHECK-NEXT:    [[Z1:%.*]] = zext i8 [[A1]] to i32
-; CHECK-NEXT:    [[A2:%.*]] = add nuw i8 [[A]], [[C2:%.*]]
-; CHECK-NEXT:    [[Z2:%.*]] = zext i8 [[A2]] to i32
-; CHECK-NEXT:    [[S:%.*]] = sub nsw i32 [[Z2]], [[Z1]]
+; CHECK-NEXT:    [[TMP1:%.*]] = zext i8 [[C2:%.*]] to i32
+; CHECK-NEXT:    [[TMP2:%.*]] = zext i8 [[C1:%.*]] to i32
+; CHECK-NEXT:    [[S:%.*]] = sub nsw i32 [[TMP1]], [[TMP2]]
 ; CHECK-NEXT:    ret i32 [[S]]
 ;
   %a1 = add nuw i8 %a, %C1
@@ -20,11 +18,9 @@
 
 define i32 @subaddnuw_c1(i8 %a, i8 %C1, i8 %C2) {
 ; CHECK-LABEL: @subaddnuw_c1(
-; CHECK-NEXT:    [[A1:%.*]] = add nuw i8 [[C1:%.*]], [[A:%.*]]
-; CHECK-NEXT:    [[Z1:%.*]] = zext i8 [[A1]] to i32
-; CHECK-NEXT:    [[A2:%.*]] = add nuw i8 [[A]], [[C2:%.*]]
-; CHECK-NEXT:    [[Z2:%.*]] = zext i8 [[A2]] to i32
-; CHECK-NEXT:    [[S:%.*]] = sub nsw i32 [[Z2]], [[Z1]]
+; CHECK-NEXT:    [[TMP1:%.*]] = zext i8 [[C2:%.*]] to i32
+; CHECK-NEXT:    [[TMP2:%.*]] = zext i8 [[C1:%.*]] to i32
+; CHECK-NEXT:    [[S:%.*]] = sub nsw i32 [[TMP1]], [[TMP2]]
 ; CHECK-NEXT:    ret i32 [[S]]
 ;
   %a1 = add nuw i8 %C1, %a
@@ -37,11 +33,9 @@
 
 define i32 @subaddnuw_c2(i8 %a, i8 %C1, i8 %C2) {
 ; CHECK-LABEL: @subaddnuw_c2(
-; CHECK-NEXT:    [[A1:%.*]] = add nuw i8 [[C1:%.*]], [[A:%.*]]
-; CHECK-NEXT:    [[Z1:%.*]] = zext i8 [[A1]] to i32
-; CHECK-NEXT:    [[A2:%.*]] = add nuw i8 [[C2:%.*]], [[A]]
-; CHECK-NEXT:    [[Z2:%.*]] = zext i8 [[A2]] to i32
-; CHECK-NEXT:    [[S:%.*]] = sub nsw i32 [[Z2]], [[Z1]]
+; CHECK-NEXT:    [[TMP1:%.*]] = zext i8 [[C2:%.*]] to i32
+; CHECK-NEXT:    [[TMP2:%.*]] = zext i8 [[C1:%.*]] to i32
+; CHECK-NEXT:    [[S:%.*]] = sub nsw i32 [[TMP1]], [[TMP2]]
 ; CHECK-NEXT:    ret i32 [[S]]
 ;
   %a1 = add nuw i8 %C1, %a
@@ -54,11 +48,9 @@
 
 define i32 @subaddnuw_c3(i8 %a, i8 %C1, i8 %C2) {
 ; CHECK-LABEL: @subaddnuw_c3(
-; CHECK-NEXT:    [[A1:%.*]] = add nuw i8 [[C1:%.*]], [[A:%.*]]
-; CHECK-NEXT:    [[Z1:%.*]] = zext i8 [[A1]] to i32
-; CHECK-NEXT:    [[A2:%.*]] = add nuw i8 [[A]], [[C2:%.*]]
-; CHECK-NEXT:    [[Z2:%.*]] = zext i8 [[A2]] to i32
-; CHECK-NEXT:    [[S:%.*]] = sub nsw i32 [[Z2]], [[Z1]]
+; CHECK-NEXT:    [[TMP1:%.*]] = zext i8 [[C2:%.*]] to i32
+; CHECK-NEXT:    [[TMP2:%.*]] = zext i8 [[C1:%.*]] to i32
+; CHECK-NEXT:    [[S:%.*]] = sub nsw i32 [[TMP1]], [[TMP2]]
 ; CHECK-NEXT:    ret i32 [[S]]
 ;
   %a1 = add nuw i8 %C1, %a
@@ -71,12 +63,7 @@
 
 define i32 @subaddnuw_const(i8 %a) {
 ; CHECK-LABEL: @subaddnuw_const(
-; CHECK-NEXT:    [[A1:%.*]] = add nuw i8 [[A:%.*]], 1
-; CHECK-NEXT:    [[Z1:%.*]] = zext i8 [[A1]] to i32
-; CHECK-NEXT:    [[A2:%.*]] = add nuw i8 [[A]], 2
-; CHECK-NEXT:    [[Z2:%.*]] = zext i8 [[A2]] to i32
-; CHECK-NEXT:    [[S:%.*]] = sub nsw i32 [[Z2]], [[Z1]]
-; CHECK-NEXT:    ret i32 [[S]]
+; CHECK-NEXT:    ret i32 1
 ;
   %a1 = add nuw i8 %a, 1
   %z1 = zext i8 %a1 to i32
@@ -88,11 +75,9 @@
 
 define i32 @subaddnsw(i8 %a, i8 %C1, i8 %C2) {
 ; CHECK-LABEL: @subaddnsw(
-; CHECK-NEXT:    [[A1:%.*]] = add nsw i8 [[A:%.*]], [[C1:%.*]]
-; CHECK-NEXT:    [[Z1:%.*]] = sext i8 [[A1]] to i32
-; CHECK-NEXT:    [[A2:%.*]] = add nsw i8 [[A]], [[C2:%.*]]
-; CHECK-NEXT:    [[Z2:%.*]] = sext i8 [[A2]] to i32
-; CHECK-NEXT:    [[S:%.*]] = sub nsw i32 [[Z2]], [[Z1]]
+; CHECK-NEXT:    [[TMP1:%.*]] = sext i8 [[C2:%.*]] to i32
+; CHECK-NEXT:    [[TMP2:%.*]] = sext i8 [[C1:%.*]] to i32
+; CHECK-NEXT:    [[S:%.*]] = sub nsw i32 [[TMP1]], [[TMP2]]
 ; CHECK-NEXT:    ret i32 [[S]]
 ;
   %a1 = add nsw i8 %a, %C1
@@ -105,12 +90,7 @@
 
 define i32 @subaddnsw_c(i8 %a) {
 ; CHECK-LABEL: @subaddnsw_c(
-; CHECK-NEXT:    [[A1:%.*]] = add nsw i8 [[A:%.*]], 1
-; CHECK-NEXT:    [[Z1:%.*]] = sext i8 [[A1]] to i32
-; CHECK-NEXT:    [[A2:%.*]] = add nsw i8 [[A]], 2
-; CHECK-NEXT:    [[Z2:%.*]] = sext i8 [[A2]] to i32
-; CHECK-NEXT:    [[S:%.*]] = sub nsw i32 [[Z2]], [[Z1]]
-; CHECK-NEXT:    ret i32 [[S]]
+; CHECK-NEXT:    ret i32 1
 ;
   %a1 = add nsw i8 %a, 1
   %z1 = sext i8 %a1 to i32
@@ -157,10 +137,9 @@
 define i32 @subaddnuw_useadd(i8 %a, i8 %C1, i8 %C2) {
 ; CHECK-LABEL: @subaddnuw_useadd(
 ; CHECK-NEXT:    [[A1:%.*]] = add nuw i8 [[A:%.*]], [[C1:%.*]]
-; CHECK-NEXT:    [[Z1:%.*]] = zext i8 [[A1]] to i32
-; CHECK-NEXT:    [[A2:%.*]] = add nuw i8 [[A]], [[C2:%.*]]
-; CHECK-NEXT:    [[Z2:%.*]] = zext i8 [[A2]] to i32
-; CHECK-NEXT:    [[S:%.*]] = sub nsw i32 [[Z2]], [[Z1]]
+; CHECK-NEXT:    [[TMP1:%.*]] = zext i8 [[C2:%.*]] to i32
+; CHECK-NEXT:    [[TMP2:%.*]] = zext i8 [[C1]] to i32
+; CHECK-NEXT:    [[S:%.*]] = sub nsw i32 [[TMP1]], [[TMP2]]
 ; CHECK-NEXT:    call void @use8(i8 [[A1]])
 ; CHECK-NEXT:    ret i32 [[S]]
 ;
@@ -177,9 +156,9 @@
 ; CHECK-LABEL: @subaddnuw_usezext(
 ; CHECK-NEXT:    [[A1:%.*]] = add nuw i8 [[A:%.*]], [[C1:%.*]]
 ; CHECK-NEXT:    [[Z1:%.*]] = zext i8 [[A1]] to i32
-; CHECK-NEXT:    [[A2:%.*]] = add nuw i8 [[A]], [[C2:%.*]]
-; CHECK-NEXT:    [[Z2:%.*]] = zext i8 [[A2]] to i32
-; CHECK-NEXT:    [[S:%.*]] = sub nsw i32 [[Z2]], [[Z1]]
+; CHECK-NEXT:    [[TMP1:%.*]] = zext i8 [[C2:%.*]] to i32
+; CHECK-NEXT:    [[TMP2:%.*]] = zext i8 [[C1]] to i32
+; CHECK-NEXT:    [[S:%.*]] = sub nsw i32 [[TMP1]], [[TMP2]]
 ; CHECK-NEXT:    call void @use32(i32 [[Z1]])
 ; CHECK-NEXT:    ret i32 [[S]]
 ;
@@ -195,10 +174,10 @@
 define i32 @subaddnuw_twouseadd(i8 %a, i8 %C1, i8 %C2) {
 ; CHECK-LABEL: @subaddnuw_twouseadd(
 ; CHECK-NEXT:    [[A1:%.*]] = add nuw i8 [[A:%.*]], [[C1:%.*]]
-; CHECK-NEXT:    [[Z1:%.*]] = zext i8 [[A1]] to i32
 ; CHECK-NEXT:    [[A2:%.*]] = add nuw i8 [[A]], [[C2:%.*]]
-; CHECK-NEXT:    [[Z2:%.*]] = zext i8 [[A2]] to i32
-; CHECK-NEXT:    [[S:%.*]] = sub nsw i32 [[Z2]], [[Z1]]
+; CHECK-NEXT:    [[TMP1:%.*]] = zext i8 [[C2]] to i32
+; CHECK-NEXT:    [[TMP2:%.*]] = zext i8 [[C1]] to i32
+; CHECK-NEXT:    [[S:%.*]] = sub nsw i32 [[TMP1]], [[TMP2]]
 ; CHECK-NEXT:    call void @use8(i8 [[A1]])
 ; CHECK-NEXT:    call void @use8(i8 [[A2]])
 ; CHECK-NEXT:    ret i32 [[S]]
@@ -240,10 +219,9 @@
 ; CHECK-NEXT:    [[Z1:%.*]] = zext i8 [[A1]] to i32
 ; CHECK-NEXT:    [[A2:%.*]] = add nuw i8 [[A]], 2
 ; CHECK-NEXT:    [[Z2:%.*]] = zext i8 [[A2]] to i32
-; CHECK-NEXT:    [[S:%.*]] = sub nsw i32 [[Z2]], [[Z1]]
 ; CHECK-NEXT:    call void @use32(i32 [[Z1]])
 ; CHECK-NEXT:    call void @use32(i32 [[Z2]])
-; CHECK-NEXT:    ret i32 [[S]]
+; CHECK-NEXT:    ret i32 1
 ;
   %a1 = add nuw i8 %a, 1
   %z1 = zext i8 %a1 to i32