Hi Tobias,
> I am inclined to say that the Intel compiler has a bug by not
> accepting it – but as written before, I regard sub-string length
> (esp. with const expr) inquiries as an odd corner case which
> is unlikely to occur in real-world code.
ok.
> Still does not work – or rather: ...%t(:)(3:4) [i.e. substring with array
> section]
> and ...%str(3:4) [i.e. substring of deferred-length scalar] both do work
> but if one combines the two (→ ...%str2(:)(3:4), i.e. substring of
> deferred-length
> array section), it does not:
>
> Array ‘r’ at (1) is a variable, which does not reduce to a constant expression
>
> for:
>
> --- a/gcc/testsuite/gfortran.dg/pr100950.f90
> +++ b/gcc/testsuite/gfortran.dg/pr100950.f90
> @@ -15,2 +15,3 @@ program p
> character(len=:), allocatable :: str
> + character(len=:), allocatable :: str2(:)
> end type t_
> @@ -24,2 +25,4 @@ program p
> integer, parameter :: l6 = len (r(1)%str (3:4))
> + integer, parameter :: l7 = len (r(1)%str2(1)(3:4))
> + integer, parameter :: l8 = len (r(1)%str2(:)(3:4))
>
>
> which feels odd.
I agree. I have revised the code slightly to accept substrings
of deferred-length. Your suggested variants now work correctly.
> In principle, LGTM – except I wonder what we do about the
> len(r(1)%str(1)(3:4));
> I think we really do handle most code available and I would like to
> close this
> topic – but still it feels a bit odd to leave this bit out.
That is handle now as discussed, see attached final patch.
Regtested again.
> I was also wondering whether we should check that the
> compile-time simplification works – i.e. use -fdump-tree-original for this;
> I attached a patch for this.
I added this to the final patch and taken the liberty to push the result
to master as d881460deb1f0bdfc3e8fa2d391a03a9763cbff4.
Thanks for your patience, given the rather extensive review...
Harald
diff --git a/gcc/fortran/simplify.c b/gcc/fortran/simplify.c
index c27b47aa98f..492867e12cb 100644
--- a/gcc/fortran/simplify.c
+++ b/gcc/fortran/simplify.c
@@ -4512,6 +4512,78 @@ gfc_simplify_leadz (gfc_expr *e)
}
+/* Check for constant length of a substring. */
+
+static bool
+substring_has_constant_len (gfc_expr *e)
+{
+ gfc_ref *ref;
+ HOST_WIDE_INT istart, iend, length;
+ bool equal_length = false;
+
+ if (e->ts.type != BT_CHARACTER)
+ return false;
+
+ for (ref = e->ref; ref; ref = ref->next)
+ if (ref->type != REF_COMPONENT && ref->type != REF_ARRAY)
+ break;
+
+ if (!ref
+ || ref->type != REF_SUBSTRING
+ || !ref->u.ss.start
+ || ref->u.ss.start->expr_type != EXPR_CONSTANT
+ || !ref->u.ss.end
+ || ref->u.ss.end->expr_type != EXPR_CONSTANT
+ || !ref->u.ss.length)
+ return false;
+
+ /* For non-deferred strings the given length shall be constant. */
+ if (!e->ts.deferred
+ && (!ref->u.ss.length->length
+ || ref->u.ss.length->length->expr_type != EXPR_CONSTANT))
+ return false;
+
+ /* Basic checks on substring starting and ending indices. */
+ if (!gfc_resolve_substring (ref, &equal_length))
+ return false;
+
+ istart = gfc_mpz_get_hwi (ref->u.ss.start->value.integer);
+ iend = gfc_mpz_get_hwi (ref->u.ss.end->value.integer);
+
+ if (istart <= iend)
+ {
+ if (istart < 1)
+ {
+ gfc_error ("Substring start index (" HOST_WIDE_INT_PRINT_DEC
+ ") at %L below 1",
+ istart, &ref->u.ss.start->where);
+ return false;
+ }
+
+ /* For deferred strings use end index as proxy for length. */
+ if (e->ts.deferred)
+ length = iend;
+ else
+ length = gfc_mpz_get_hwi (ref->u.ss.length->length->value.integer);
+ if (iend > length)
+ {
+ gfc_error ("Substring end index (" HOST_WIDE_INT_PRINT_DEC
+ ") at %L exceeds string length",
+ iend, &ref->u.ss.end->where);
+ return false;
+ }
+ length = iend - istart + 1;
+ }
+ else
+ length = 0;
+
+ /* Fix substring length. */
+ e->value.character.length = length;
+
+ return true;
+}
+
+
gfc_expr *
gfc_simplify_len (gfc_expr *e, gfc_expr *kind)
{
@@ -4521,7 +4593,8 @@ gfc_simplify_len (gfc_expr *e, gfc_expr *kind)
if (k == -1)
return &gfc_bad_expr;
- if (e->expr_type == EXPR_CONSTANT)
+ if (e->expr_type == EXPR_CONSTANT
+ || substring_has_constant_len (e))
{
result = gfc_get_constant_expr (BT_INTEGER, k, &e->where);
mpz_set_si (result->value.integer, e->value.character.length);
diff --git a/gcc/testsuite/gfortran.dg/pr100950.f90 b/gcc/testsuite/gfortran.dg/pr100950.f90
new file mode 100644
index 00000000000..cb9d126bc18
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/pr100950.f90
@@ -0,0 +1,53 @@
+! { dg-do run }
+! { dg-additional-options "-fdump-tree-original" }
+! PR fortran/100950 - ICE in output_constructor_regular_field, at varasm.c:5514
+
+program p
+ character(8), parameter :: u = "123"
+ character(8) :: x = "", s
+ character(2) :: w(2) = [character(len(x(3:4))) :: 'a','b' ]
+ character(*), parameter :: y(*) = [character(len(u(3:4))) :: 'a','b' ]
+ character(*), parameter :: z(*) = [character(len(x(3:4))) :: 'a','b' ]
+ character(*), parameter :: t(*) = [character(len(x( :2))) :: 'a','b' ]
+ character(*), parameter :: v(*) = [character(len(x(7: ))) :: 'a','b' ]
+ type t_
+ character(len=5) :: s
+ character(len=8) :: t(4)
+ character(len=8), pointer :: u(:)
+ character(len=:), allocatable :: str
+ character(len=:), allocatable :: str2(:)
+ end type t_
+ type(t_) :: q, r(1)
+ integer, parameter :: lq = len (q%s(3:4)), lr = len (r%s(3:4))
+ integer, parameter :: l1 = len (q %t(1)(3:4))
+ integer, parameter :: l2 = len (q %t(:)(3:4))
+ integer, parameter :: l3 = len (q %str (3:4))
+ integer, parameter :: l4 = len (r(:)%t(1)(3:4))
+ integer, parameter :: l5 = len (r(1)%t(:)(3:4))
+ integer, parameter :: l6 = len (r(1)%str (3:4))
+ integer, parameter :: l7 = len (r(1)%str2(1)(3:4))
+ integer, parameter :: l8 = len (r(1)%str2(:)(3:4))
+
+ if (len (y) /= 2) stop 1
+ if (len (z) /= 2) stop 2
+ if (any (w /= y)) stop 3
+ if (len ([character(len(u(3:4))) :: 'a','b' ]) /= 2) stop 4
+ if (len ([character(len(x(3:4))) :: 'a','b' ]) /= 2) stop 5
+ if (any ([character(len(x(3:4))) :: 'a','b' ] /= y)) stop 6
+ write(s,*) [character(len(x(3:4))) :: 'a','b' ]
+ if (s /= " a b ") stop 7
+ if (len (t) /= 2) stop 8
+ if (len (v) /= 2) stop 9
+ if (lq /= 2 .or. lr /= 2) stop 10
+ if (l1 /= 2 .or. l2 /= 2 .or. l4 /= 2 .or. l5 /= 2) stop 11
+ if (l3 /= 2 .or. l6 /= 2 .or. l7 /= 2 .or. l8 /= 2) stop 12
+
+ block
+ integer, parameter :: l9 = len (r(1)%u(:)(3:4))
+ if (l9 /= 2) stop 13
+ end block
+end
+
+! { dg-final { scan-tree-dump-times "_gfortran_stop_numeric" 2 "original" } }
+! { dg-final { scan-tree-dump "_gfortran_stop_numeric \\(3, 0\\);" "original" } }
+! { dg-final { scan-tree-dump "_gfortran_stop_numeric \\(7, 0\\);" "original" } }
