avr-gcc extern __flash array bug

array.c

#include <stdint.h>

extern __flash const uint8_t digital_pin_to_bit_mask_PGM[];

uint8_t read_array(uint8_t i)
{
  return digital_pin_to_bit_mask_PGM[i];        // bug: uses ld
  // return *(digital_pin_to_bit_mask_PGM + i);    // uses lpm
}

array.ino

void setup() {
  // put your setup code here, to run once:

}

extern "C" uint8_t read_array(uint8_t index);
void loop() {
  // put your main code here, to run repeatedly:
  PORTB = read_array(PINB);
}