Index: llvm/test/Transforms/InstCombine/addsub-constant-folding.ll
===================================================================
--- llvm/test/Transforms/InstCombine/addsub-constant-folding.ll
+++ llvm/test/Transforms/InstCombine/addsub-constant-folding.ll
@@ -132,6 +132,47 @@
   ret i32 %t1
 }
 
+define i32 @add_nsw_const_const_sub_nsw(i32 %arg) {
+; CHECK-LABEL: @add_nsw_const_const_sub_nsw(
+; CHECK-NEXT:    [[T1:%.*]] = sub i32 -2147483648, [[ARG:%.*]]
+; CHECK-NEXT:    ret i32 [[T1]]
+;
+  %t0 = add nsw i32 %arg, 1
+  %t1 = sub nsw i32 -2147483647, %t0
+  ret i32 %t1
+}
+
+define i32 @add_nsw_const_const_sub(i32 %arg) {
+; CHECK-LABEL: @add_nsw_const_const_sub(
+; CHECK-NEXT:    [[T1:%.*]] = sub i32 -2147483648, [[ARG:%.*]]
+; CHECK-NEXT:    ret i32 [[T1]]
+;
+  %t0 = add nsw i32 %arg, 1
+  %t1 = sub i32 -2147483647, %t0
+  ret i32 %t1
+}
+
+define i32 @add_const_const_sub_nsw(i32 %arg) {
+; CHECK-LABEL: @add_const_const_sub_nsw(
+; CHECK-NEXT:    [[T1:%.*]] = sub i32 -2147483648, [[ARG:%.*]]
+; CHECK-NEXT:    ret i32 [[T1]]
+;
+  %t0 = add i32 %arg, 1
+  %t1 = sub nsw i32 -2147483647, %t0
+  ret i32 %t1
+}
+
+; 2147483647-X with nsw will be more poisonous than -2147483647-(X+2) with nsw. (see X = -1)
+define i32 @add_nsw_const_const_sub_nsw_ov(i32 %arg) {
+; CHECK-LABEL: @add_nsw_const_const_sub_nsw_ov(
+; CHECK-NEXT:    [[T1:%.*]] = sub i32 2147483647, [[ARG:%.*]]
+; CHECK-NEXT:    ret i32 [[T1]]
+;
+  %t0 = add nsw i32 %arg, 2
+  %t1 = sub nsw i32 -2147483647, %t0
+  ret i32 %t1
+}
+
 define i32 @add_const_const_sub_extrause(i32 %arg) {
 ; CHECK-LABEL: @add_const_const_sub_extrause(
 ; CHECK-NEXT:    [[T0:%.*]] = add i32 [[ARG:%.*]], 8