libyuv conversion code highlighting a potential clang bug

convert_libyuv_clang_bug.cc

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

int main(void) {
  constexpr int bsize = 128 * 10;
  constexpr int stride = 128;
  uint8_t buf[4][bsize];
  uint8_t pvalue[4] = {29, 255, 107, 255};

  for (int p = 0; p < 4; ++p) {
    uint8_t* pdata = buf[p];
    for (int y = 0; y < 10; ++y) {
      for (int x = 0; x < 128; ++x) {
        pdata[x] = (x < 16) ? pvalue[p] : 0;
      }
      pdata += stride;
    }
  }
  fprintf(stderr, "\n\n");

  uint8_t rgb[100 * 10];
  int rgbstride = 100;
  int width = 14;

  libyuv::I444AlphaToARGBMatrix(buf[0], stride, buf[1], stride, buf[2], stride,
                                buf[3], stride, rgb, rgbstride,
                                &libyuv::kYuvI601Constants, width, 10, 0);

  uint8_t* base_data = rgb;
  for (int y = 0; y < 10; ++y) {
    uint8_t* pdata = base_data;
    for (int x = 0; x < width; ++x) {
      fprintf(stderr, "### (%d, %d) %d %d %d %d\n", y, x, pdata[1], pdata[2],
              pdata[3], pdata[0]);
      pdata += 4;
    }
    base_data += rgbstride;
  }

  fprintf(stderr, "hello\n");
  return 0;
}