为什么优化器会修复我的程序？

I've got a simple C program to run some matrix matrix multiplication for some tests:

我有一个简单的C程序来运行一些矩阵矩阵乘法进行一些测试：

#include <stdio.h>
#include <stdlib.h>
#include <time.h>

#define N  1000
#define R_M 100

void disp_matrix(double A[N][N]);

int main()
{

  clock_t begin, end;
  double time_spent;

  begin = clock();

  int seed = 1;
  srand(seed);
  double A[N][N];
  double B[N][N];
  double C[N][N];
  for(int i = 0; i < N; i++){
    for(int j = 0; j < N; j++){
      A[i][j] = (double)rand()/(double)(RAND_MAX/R_M);
      B[i][j] = (double)rand()/(double)(RAND_MAX/R_M);
      C[i][j] = 0.;
    }
  }

  for(int i = 0; i < N; i++){
    for(int k = 0; k < N; k++){
      for(int j = 0; j < N; j++){
    C[i][k] += A[i][j] * B[j][k];
      }
    }
  }

  end = clock();
  time_spent = (double)(end - begin) / CLOCKS_PER_SEC;
  printf("Time spent: %f\n", time_spent );
  /* disp_matrix(C); */
  return 0;
}

void disp_matrix(double A[N][N]){
  for(int i = 0; i < N; i++){
    for(int j = 0; j < N; j++){
      printf("%10.3g",A[i][j]);
    }
    printf("\n");
  }
  return;
}

If I compile with:

如果我编译：

gcc -Wall -std=c11 -O2 test.c -o test && ./test

The program will run fine, however, if I run:

程序运行正常，但是，如果我运行：

gcc -Wall -std=c11 test.c -o test && ./test
/bin/bash: Zeile 1: 10617 Speicherzugriffsfehler  ./test

C will compile fine, but the execution of the program gives me an segmentation fault (Speicherzugriffsfehler). I really can not figure out why it would do it this way.

C将编译正常，但程序的执行给我一个分段错误（Speicherzugriffsfehler）。我真的无法弄清楚为什么会这样做。

Why does the optimization "fix" my program and where is the original error. I should have plenty of memory for arrays of such a small size.

为什么优化“修复”我的程序以及原始错误在哪里。对于如此小的数组，我应该有足够的内存。

2 个解决方案

#1

The root of the problem is the huge arrays on the stack, resulting a stack overflow, leading to a seg fault event,

问题的根源是堆栈上的巨大数组，导致堆栈溢出，导致seg错误事件，

Suggest move the arrays to file scope from their current main() function scope.

建议将数组从其当前的main（）函数范围移动到文件范围。

#2

As suggested in some of the comments, the array was to big for a static definition. I used malloc() and it worked fine.

正如一些评论中所建议的那样，数组对于静态定义来说很重要。我使用了malloc（），它运行良好。

Edit: Also,(as commented) the optimiziation 'fixes' my program, because I don't use C and it is therefore not calculated.

编辑：另外，（评论）优化'修复'我的程序，因为我不使用C，因此不计算。

#1