[Bug c/29826] New: __attribute__ dllimport makes optimization crash on cygwin

[Denis dot Excoffier at airbus dot com]

the exact version of GCC is 4.1.1
the system type is i686-pc-cygwin
the options given when GCC was configured/built:
  --prefix=/tmp/local/unixutil/gcc-4.1.1
  --with-local-prefix=/usr/local/myCompanyName
  ("myCompanyName" is not the exact wording)
  (also, there is a symlink /tmp/local/unixutil/gcc -> gcc-4.1.1)
the complete command line that triggers the bug:
  /tmp/local/unixutil/gcc/bin/gcc -O -Wall -Wextra -c zim.c
the compiler output (error messages, warnings, etc.):
  stdout: nothing
  stderr:
    zim.c: In function 'ffff':
    zim.c:16: error: unrecognizable insn:
    (insn 20 19 21 2 (set (reg:SI 66)
            (const:SI (plus:SI (mem:SI (symbol_ref:SI ("#i.vvvv") <var_decl
0x194500b0 vvvv>) [0 S4 A8])
                    (const_int 4 [0x4])))) -1 (nil)
        (nil))
    zim.c:16: internal compiler error: in extract_insn, at recog.c:2084
    Please submit a full bug report,
    with preprocessed source if appropriate.
    See <URL:http://gcc.gnu.org/bugs.html> for instructions.
  zim.o: not created
the preprocessed file: see below
additional remarks:
  1) if "-O" is removed, all seems OK
  2) if "__attribute__((dllimport))" is removed, all seems OK
  3) if "-Wall" or "-Wextra" is removed, no change (still crash)


---zim.i-----------------------------------------------------
# 1 "zim.c"
# 1 "<built-in>"
# 1 "<command line>"
# 1 "zim.c"
struct ssss {
  const char *xxxx1;
  const char *xxxx2;
};

extern __attribute__((dllimport)) struct ssss vvvv[];

int zzzz();

int ffff() {
  int i;
  for (i = 0; i < 2; i++) {
    zzzz(vvvv[i].xxxx2);
  };
  return(0);
};
-------------------------------------------------------------


-- 
           Summary: __attribute__ dllimport makes optimization crash on
                    cygwin
           Product: gcc
           Version: 4.1.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: Denis dot Excoffier at airbus dot com
 GCC build triplet: i686-pc-cygwin
  GCC host triplet: i686-pc-cygwin
GCC target triplet: i686-pc-cygwin


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29826