const关键字在断点调试时为什么可以看到值被改变？

#include<iostream>
 //const关键字保护变量不可被改变
 /*const_demo.cpp
 问题描述：
 加断点调试时可以看到a的值在*p赋值后变成了8，但由于const的
 作用最后输出的还是7。问题是：为什么在断点调试时可以看到a变
 成了8？
 */
using namespace std;
 
int main(void)
{
    const int  a = 7;
    int  *p = (int*)&a;
    *p = 8;
    cout<<a;
    return 0;
}

我用vscode测试*p 是 7啊

From https://en.cppreference.com/w/cpp/language/cv

const object - an object whose type is const-qualified, or a non-mutable subobject of a const object. Such object cannot be modified: attempt to do so directly is a compile-time error, and attempt to do so indirectly (e.g., by modifying the const object through a reference or pointer to non-const type) results in undefined behavior.

因为const变量a被优化到寄存器上了，而通过p访问的a是内存中的a。