[stubs] Introduce AddStub and SubtractStub.

src/compiler/code-stub-assembler.cc

Index: src/compiler/code-stub-assembler.cc
diff --git a/src/compiler/code-stub-assembler.cc b/src/compiler/code-stub-assembler.cc
index 741ce521e7c94ce2126581e036bedd8d407d5112..89a21d7245599417da3315fd2bc97503aea650f3 100644
--- a/src/compiler/code-stub-assembler.cc
+++ b/src/compiler/code-stub-assembler.cc
@@ -175,6 +175,16 @@ Node* CodeStubAssembler::SmiToFloat64(Node* value) {
 
 Node* CodeStubAssembler::SmiAdd(Node* a, Node* b) { return IntPtrAdd(a, b); }
 
+Node* CodeStubAssembler::SmiAddWithOverflow(Node* a, Node* b) {
+  return IntPtrAddWithOverflow(a, b);
+}
+
+Node* CodeStubAssembler::SmiSub(Node* a, Node* b) { return IntPtrSub(a, b); }
+
+Node* CodeStubAssembler::SmiSubWithOverflow(Node* a, Node* b) {
+  return IntPtrSubWithOverflow(a, b);
+}
+
 Node* CodeStubAssembler::SmiEqual(Node* a, Node* b) { return WordEqual(a, b); }
 
 Node* CodeStubAssembler::SmiLessThan(Node* a, Node* b) {