https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88249
kargl at gcc dot gnu.org changed: What |Removed |Added ---------------------------------------------------------------------------- Priority|P3 |P4 Status|UNCONFIRMED |NEW Last reconfirmed| |2018-11-30 Ever confirmed|0 |1 --- Comment #1 from kargl at gcc dot gnu.org --- (In reply to G. Steinmetz from comment #0) > With a missing file-unit-number, down to at least gcc-5 : > > > $ cat z1.f90 > program p > backspace (err=1) > endfile (err=1) > flush (err=1) > rewind (err=1) > end > > > $ gfortran-9-20181125 -c z1.f90 > f951: internal compiler error: Segmentation fault > 0xb2bcff crash_signal > ../../gcc/toplev.c:326 > 0x63f696 gfc_resolve_filepos(gfc_filepos*) > ../../gcc/fortran/io.c:2853 > 0x6850ab gfc_resolve_code(gfc_code*, gfc_namespace*) > ../../gcc/fortran/resolve.c:11547 > 0x68702f resolve_codes Index: gcc/fortran/resolve.c =================================================================== --- gcc/fortran/resolve.c (revision 266386) +++ gcc/fortran/resolve.c (working copy) @@ -11544,7 +11544,7 @@ start: case EXEC_ENDFILE: case EXEC_REWIND: case EXEC_FLUSH: - if (!gfc_resolve_filepos (code->ext.filepos)) + if (!gfc_resolve_filepos (code->ext.filepos, &code->loc)) break; resolve_branch (code->ext.filepos->err, code); Index: gcc/fortran/io.c =================================================================== --- gcc/fortran/io.c (revision 266386) +++ gcc/fortran/io.c (working copy) @@ -2834,22 +2834,21 @@ cleanup: bool -gfc_resolve_filepos (gfc_filepos *fp) +gfc_resolve_filepos (gfc_filepos *fp, locus *where) { RESOLVE_TAG (&tag_unit, fp->unit); RESOLVE_TAG (&tag_iostat, fp->iostat); RESOLVE_TAG (&tag_iomsg, fp->iomsg); - if (!gfc_reference_st_label (fp->err, ST_LABEL_TARGET)) - return false; - if (!fp->unit && (fp->iostat || fp->iomsg)) + if (!fp->unit && (fp->iostat || fp->iomsg || fp->err)) { - locus where; - where = fp->iostat ? fp->iostat->where : fp->iomsg->where; - gfc_error ("UNIT number missing in statement at %L", &where); + gfc_error ("UNIT number missing in statement at %L", where); return false; } + if (!gfc_reference_st_label (fp->err, ST_LABEL_TARGET)) + return false; + if (fp->unit->expr_type == EXPR_CONSTANT && fp->unit->ts.type == BT_INTEGER && mpz_sgn (fp->unit->value.integer) < 0)