[Bug c/98132] New: ‘target_mem_ref’ not supported by expression internal error

[thutt at vmware dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98132

            Bug ID: 98132
           Summary: ‘target_mem_ref’ not supported by expression internal
                    error
           Product: gcc
           Version: 6.4.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: thutt at vmware dot com
  Target Milestone: ---

#if 0
The program below, compiled with:

   x86_64-vmk-linux-gnu-gcc (GCC) 6.4.0
   Copyright (C) 2017 Free Software Foundation, Inc.
   This is free software; see the source for copying conditions.  There is NO
   warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

fails with the following internal gcc error and an incorrect warning:

  #‘target_mem_ref’ not supported by expression#’./main.c: In function ‘main’:
  ./main.c:15:12: warning:  is used uninitialized in this function
[-Wuninitialized]
      return (*(uint16*)&ote.field[i] >> i) & 0x1ff;
              ^~~~~~~~~~~~~~~~~~~~~~~
  ./main.c:19:1: note: ‘ote’ was declared here
   f1(t0_t ote)
   ^~

The compiler used was built in-house.

The command line is:

  CC=<path to gcc>

  ${CC}                                           \
      -nostdinc                                   \
      -O2                                         \
      -Wuninitialized                             \
      -o ./main.o                                 \
      -c ./main.c

#endif


typedef unsigned char uint8;
typedef unsigned short int uint16;

typedef struct t0_t {
   uint8 field[5];
} t0_t;

extern t0_t ote;

static unsigned
f0(t0_t ote, unsigned i)
{
   return (*(uint16*)&ote.field[i] >> i) & 0x1ff;
}

static unsigned
f1(t0_t ote)
{
   int i;
   for (i = 0; i < 4; i++) {
      unsigned j = f0(ote, i);
      if (j == 1) {
         return 1;
      }
   }
   return 0;
}

int
main(int argc, char **argv)
{
   return f1(ote);
}