On Sun, Nov 30, 2008 at 5:28 AM, Steve Kargl <[EMAIL PROTECTED]> wrote: > First, I'll preface this with "I'm probably doing something wrong." > I'm adding support to gfortran for the ERRMSG argument to [DE]ALLOCATE. > Here's, some code to demonstrate: > > program a > call works > call fails > end program a > ! > ! Work with all optimization levels. > ! > subroutine works > character(len=70) :: err = 'No error' > integer, allocatable :: i(:) > allocate(i(4), errmsg=err) ! err is unchanged. > print *, err > deallocate(i) > allocate(i(4), i(5), errmsg=err) ! err is assigned an error message. > print *, err > end subroutine works > ! > ! Fails at -O[123] due to len=30, works with -O0. > ! > subroutine fails > character(len=30) :: err = 'No error' > integer, allocatable :: i(:) > allocate(i(4), errmsg=err) > print *, err > deallocate(i) > allocate(i(4), i(5), errmsg=err) > print *, err > end subroutine fails > > kargl[222] gfc4x -o z -fdump-tree-original a.f90 > kargl[223] ./z > No error > Attempt to deallocate an unallocated object > No error > Attempt to deallocate an unall > kargl[224] mv a.f90.003t.original abc > kargl[225] gfc4x -o z -fdump-tree-original -O a.f90 > a.f90: In function 'fails': > a.f90:16: error: non-trivial conversion at assignment > character(kind=1) * > character(kind=1)[1:30] > iftmp.17 = err; > > a.f90:16: error: non-trivial conversion at assignment > character(kind=1) * > character(kind=1)[1:30] > iftmp.20 = err; > > a.f90:16: internal compiler error: verify_gimple failed > Please submit a full bug report, > with preprocessed source if appropriate. > See <http://gcc.gnu.org/bugs.html> for instructions. > > Looking at a diff of the two -fdump-tree-original outputs shows: > > ERRMSG.12 = &"Attempt to deallocate an unallocated object"[1]{lb: 1 sz: > 1}; > - ERRMSG.12 = stat.11 != 0 ? (void) __builtin_memcpy ((void *) &err, (void > *) ERRMSG.12, 30) : (void) 0; > + ERRMSG.12 = stat.11 != 0 ? err = *(character(kind=1)[1:30] * {ref-all}) > ERRMSG.12 : (void) 0; > > The chunk of code that I've add to trans-stmt.c(gfc_trans_deallocate) looks > like > > /* A better error message may be possible, but not required. */ > const char *msg = "Attempt to deallocate an unallocated object"; > tree errmsg, slen, dlen; > > gfc_init_se (&se, NULL); > gfc_conv_expr_lhs (&se, code->expr); > > errmsg = gfc_create_var (pchar_type_node, "ERRMSG"); > > /* astat is >= 0. */ > tmp = fold_build2 (NE_EXPR, boolean_type_node, astat, > build_int_cst (TREE_TYPE (astat), 0)); > > /* Create tree for msg. */ > gfc_add_modify (&block, errmsg, > gfc_build_addr_expr (pchar_type_node, > gfc_build_localized_cstring_const (msg))); > > /* Don't overflow the string. slen = min(dlen, len). */ > slen = build_int_cst (gfc_charlen_type_node, 44); > dlen = gfc_get_expr_charlen (code->expr); > slen = fold_build2 (MIN_EXPR, TREE_TYPE (slen), dlen, slen); > > tmp = fold_build3 (COND_EXPR, pchar_type_node, tmp, > build_call_expr (built_in_decls[BUILT_IN_MEMCPY], 3, > se.expr, errmsg, slen), > build_empty_stmt ()); > > gfc_add_modify (&block, errmsg, tmp); > > The diff shows that the fails case correctly has dlen=30 > and in fact for any value less than slen=44 and -O[123] > removes the __builtin_memcpy(). So what is missing or > how to I inhibit this optimization?
You cannot inhibit this optimization, instead the optimization should be fixed to not generate invalid gimple ;) (see builtins.c:fold_builtin_memory_op) Richard.
