[Bug c++/59354] Unexpected result in g++ when casting int to char from an stl vector to an array

["gcc-bugzilla at contacts dot eelis.net" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=59354

Eelis <gcc-bugzilla at contacts dot eelis.net> changed:

           What    |Removed                     |Added
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                 CC|                            |gcc-bugzilla at contacts dot eelis
                   |                            |.net

--- Comment #1 from Eelis <gcc-bugzilla at contacts dot eelis.net> ---
This is not specific to std::vector and not specific to C++.

C testcase:

  #include <stdio.h>
  #include <stdint.h>

  int main()
  {
    uint32_t a[256] = {};
    uint8_t b[1000] = {};

    for(int i = 0; i != 256; ++i)
      a[i] = i % 5;

    for (int z = 0 ; z < 16; z++)
    for (int y = 0 ; y <  4; y++)
    for (int x = 0 ; x <  4; x++)
      b[y * 64 + z*4 + x] = a[z * 16 + y * 4 + x];

    printf("%d\n", b[4]);

    return 0;
  }

Prints '4' without -mno-sse, prints '1' with -mno-sse.