[Patch] Fortran: Fix gfc_conv_gfc_desc_to_cfi_desc with NULL [PR104126]

[Patch] Fortran: Fix gfc_conv_gfc_desc_to_cfi_desc with NULL [PR104126]

[Tobias Burnus]

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Pre-remark: Related NULL, there some accepts-invalid issues, not addressed in this
patch. See https://gcc.gnu.org/PR104819

This patch fixes an ICE (12 regression) with NULL() that has no MOLD argument.

OK for mainline?

Tobias
-----------------
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Fortran: Fix gfc_conv_gfc_desc_to_cfi_desc with NULL [PR104126]

	PR fortran/104126

gcc/fortran/ChangeLog:

	* trans-expr.cc (gfc_conv_gfc_desc_to_cfi_desc): Handle NULL
	without MOLD.

gcc/testsuite/ChangeLog:

	* gfortran.dg/null_actual_2.f90: New test.

 gcc/fortran/trans-expr.cc                   | 13 +++++++++----
 gcc/testsuite/gfortran.dg/null_actual_2.f90 | 16 ++++++++++++++++
 2 files changed, 25 insertions(+), 4 deletions(-)

diff --git a/gcc/fortran/trans-expr.cc b/gcc/fortran/trans-expr.cc
index eb6a78c3a62..e8a78ccf4e1 100644
--- a/gcc/fortran/trans-expr.cc
+++ b/gcc/fortran/trans-expr.cc
@@ -5608,8 +5608,11 @@ gfc_conv_gfc_desc_to_cfi_desc (gfc_se *parmse, gfc_expr *e, gfc_symbol *fsym)
     itype = (e->ts.u.derived->intmod_sym_id == ISOCBINDING_FUNPTR
 	     ? CFI_type_cfunptr : CFI_type_cptr);
   else
-    switch (e->ts.type)
-      {
+    {
+      if (e->expr_type == EXPR_NULL && e->ts.type == BT_UNKNOWN)
+	e->ts = fsym->ts;
+      switch (e->ts.type)
+	{
 	case BT_INTEGER:
 	case BT_LOGICAL:
 	case BT_REAL:
@@ -5647,7 +5650,8 @@ gfc_conv_gfc_desc_to_cfi_desc (gfc_se *parmse, gfc_expr *e, gfc_symbol *fsym)
 	case BT_UNKNOWN:
 	  // FIXME: Really unreachable? Or reachable for type(*) ? If so, CFI_type_other?
 	  gcc_unreachable ();
-      }
+	}
+    }
 
   tmp = gfc_get_cfi_desc_type (cfi);
   gfc_add_modify (&block, tmp,
@@ -5700,7 +5704,8 @@ gfc_conv_gfc_desc_to_cfi_desc (gfc_se *parmse, gfc_expr *e, gfc_symbol *fsym)
   gfc_init_block (&block2);
 
   /* Set elem_len, which may be only known at run time. */
-  if (e->ts.type == BT_CHARACTER)
+  if (e->ts.type == BT_CHARACTER
+      && (e->expr_type != EXPR_NULL || gfc_strlen != NULL_TREE))
     {
       gcc_assert (gfc_strlen);
       tmp = gfc_strlen;
diff --git a/gcc/testsuite/gfortran.dg/null_actual_2.f90 b/gcc/testsuite/gfortran.dg/null_actual_2.f90
new file mode 100644
index 00000000000..de481f01295
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/null_actual_2.f90
@@ -0,0 +1,16 @@
+! { dg-do compile }
+!
+! PR fortran/104126
+!
+! Contributed by G. Steinmetz 
+!
+program p
+   use iso_c_binding, only: c_char
+   character(len=:,kind=c_char), pointer :: d
+   call s(null(d))
+   call s(null())
+contains
+   subroutine s(x) bind(c)
+      character(len=:, kind=c_char), pointer, intent(in) :: x
+   end
+end

Re: [Patch] Fortran: Fix gfc_conv_gfc_desc_to_cfi_desc with NULL [PR104126]

[Harald Anlauf]

Hi Tobias,

Am 07.03.22 um 15:16 schrieb Tobias Burnus:
> Pre-remark: Related NULL, there some accepts-invalid issues, not
> addressed in this
> patch. See https://gcc.gnu.org/PR104819
>
> This patch fixes an ICE (12 regression) with NULL() that has no MOLD
> argument.

the patch does fix the ICE.  But given your short pre-remark:
are you saying that the testcase is invalid, and with the patch
we silently accept it now?

(The testcase compiles with Intel, but triggers a funny bug in
crayftn, which made me read 16.9.144 to learn more about the
tricks of NULL.  But I tend to think this case is valid.)

> OK for mainline?

LGTM.

Thanks for the patch!

Harald

> Tobias
> -----------------
> Siemens Electronic Design Automation GmbH; Anschrift: Arnulfstraße 201,
> 80634 München; Gesellschaft mit beschränkter Haftung; Geschäftsführer:
> Thomas Heurung, Frank Thürauf; Sitz der Gesellschaft: München;
> Registergericht München, HRB 106955

Re: [Patch] Fortran: Fix gfc_conv_gfc_desc_to_cfi_desc with NULL [PR104126]

[Harald Anlauf]

Hi Tobias,

Am 07.03.22 um 15:16 schrieb Tobias Burnus:
> Pre-remark: Related NULL, there some accepts-invalid issues, not 
> addressed in this
> patch. See https://gcc.gnu.org/PR104819
> 
> This patch fixes an ICE (12 regression) with NULL() that has no MOLD 
> argument.

the patch does fix the ICE.  But given your short pre-remark:
are you saying that the testcase is invalid, and with the patch
we silently accept it now?

(The testcase compiles with Intel, but triggers a funny bug in
crayftn, which made me read 16.9.144 to learn more about the
tricks of NULL.  But I tend to think this case is valid.)

> OK for mainline?

LGTM.

Thanks for the patch!

Harald

> Tobias
> -----------------
> Siemens Electronic Design Automation GmbH; Anschrift: Arnulfstraße 201, 
> 80634 München; Gesellschaft mit beschränkter Haftung; Geschäftsführer: 
> Thomas Heurung, Frank Thürauf; Sitz der Gesellschaft: München; 
> Registergericht München, HRB 106955

Re: [Patch] Fortran: Fix gfc_conv_gfc_desc_to_cfi_desc with NULL [PR104126]

[Tobias Burnus]

Hi Harald,

On 08.03.22 22:44, Harald Anlauf wrote:
> Am 07.03.22 um 15:16 schrieb Tobias Burnus:
>> Pre-remark: Related NULL, there some accepts-invalid issues, not
>> addressed in this
>> patch. See https://gcc.gnu.org/PR104819
>>
>> This patch fixes an ICE (12 regression) with NULL() that has no MOLD
>> argument.
> the patch does fix the ICE.  But given your short pre-remark:
> are you saying that the testcase is invalid, and with the patch
> we silently accept it now?

Sorry for being confusing. I also believe the testcase of the just
committed patch is valid Fortran.

However, when fixing this PR, I was looking at the spec – and saw that
GCC accepts invalid code using NULL(), which is not diagnosed. Those
issues are orthogonal to this patch, except that the accepts-invalid
issues also are about NULL().

Thanks for the review!

Tobias

-----------------
Siemens Electronic Design Automation GmbH; Anschrift: Arnulfstraße 201, 80634 München; Gesellschaft mit beschränkter Haftung; Geschäftsführer: Thomas Heurung, Frank Thürauf; Sitz der Gesellschaft: München; Registergericht München, HRB 106955