为什么优化会将 double 转换为无符号 int 的结果？

问：

给定此代码：（https://godbolt.org/z/qGneEne7x)

#include <stdio.h>
#include <xmmintrin.h>

int main ()
{
    double d[2] = { 161785254.0, -215713672.0 };
    int i[4];
    unsigned u[4];

    __m128d vd = _mm_loadu_pd(d);
    __m128i vi = _mm_cvtpd_epi32(vd);
    _mm_storeu_si128((void *)i, vi);
    _mm_storeu_si128((void *)u, vi);

    printf("Doubles to convert            : %.1f %.1f\n", d[0], d[1]);
    printf("\n");
    printf("SIMD double to signed int     : %i   %i\n", i[0], i[1]);
    printf("SIMD double stored to unsigned: %u   %u\n", u[0], u[1]);
    printf("\n");
    printf("Scalar double to signed int   : %i   %i\n", (int)d[0], (int)d[1]);
    printf("Scalar double to unsigned     : %u   %u\n", (unsigned)d[0], (unsigned)d[1]);
}

为什么优化会更改标量代码中双号到无符号转换的结果？

这是它用 -O0 打印出来的内容：

Doubles to convert            : 161785254.0 -215713672.0

SIMD double to signed int     : 161785254   -215713672
SIMD double stored to unsigned: 161785254   4079253624

Scalar double to signed int   : 161785254   -215713672
Scalar double to unsigned     : 161785254   4079253624

一切都如预期的那样。

打开 -O1 并将标量变为 unsigned 变为零：

Scalar double to unsigned     : 161785254   0

为什么？