BUG: -funroll-all-loops generates unresolved externals

[Manfred Hollstein]

Hi there,

When  bootstrapping a  recent  checkout from the   mainline sources on
i586-redhat6-linux-gnu   using  BOOT_CFLAGS="-O9 -funroll-all-loops" I
ended up with an unresolved external while creating cc1chill.

Further analysis has shown, that compiling loops of the following form
using -funroll-all-loops generates  jumps to labels, which won't exist
in the final output any more:

  for (;;)
    {
      ch = input ();
      if (ISALNUM (ch))
        obstack_1grow (&temporary_obstack, ch);
      else if (ch != '_')
        break;
    }

Rewriting this loop to  use a do { ...  } while (...) construct can be
used as a work-around:

  do
    {
      ch = input ();
      if (ISALNUM (ch))
        obstack_1grow (&temporary_obstack, ch);
    } while (ch == '_');

BTW, this is an excerpt from gcc/ch/lex.c.

OK to install the attached testcase?

Cheers, manfred.