[Patch, fortran] PR fortran/82376 - Duplicate function call using -fcheck=pointer

[Patch, fortran] PR fortran/82376 - Duplicate function call using -fcheck=pointer

[José Rui Faustino de Sousa]

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Hi All!

Proposed patch to:

PR82376 - Duplicate function call using -fcheck=pointer

Patch tested only on x86_64-pc-linux-gnu.

Evaluate function result and then pass a pointer, instead of a reference 
to the function itself, thus avoiding multiple evaluations of the function.

Thank you very much.

Best regards,
José Rui

Fortran: Fix double function call with -fcheck=pointer [PR]

gcc/fortran/ChangeLog:

	PR fortran/82376
	* trans-expr.c (gfc_conv_procedure_call): Evaluate function result
	and then pass a pointer.

gcc/testsuite/ChangeLog:

	PR fortran/82376
	* gfortran.dg/PR82376.f90: New test.


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diff --git a/gcc/fortran/trans-expr.c b/gcc/fortran/trans-expr.c
index 213f32b0a67..b83b021755d 100644
--- a/gcc/fortran/trans-expr.c
+++ b/gcc/fortran/trans-expr.c
@@ -6014,11 +6014,8 @@ gfc_conv_procedure_call (gfc_se * se, gfc_symbol * sym,
 			    || (!e->value.function.esym
 				&& e->symtree->n.sym->attr.pointer))
 			&& fsym && fsym->attr.target)
-		{
-		  gfc_conv_expr (&parmse, e);
-		  parmse.expr = gfc_build_addr_expr (NULL_TREE, parmse.expr);
-		}
-
+		/* Make sure the function only gets called once.  */
+		gfc_conv_expr_reference (&parmse, e, false);
 	      else if (e->expr_type == EXPR_FUNCTION
 		       && e->symtree->n.sym->result
 		       && e->symtree->n.sym->result != e->symtree->n.sym
diff --git a/gcc/testsuite/gfortran.dg/PR82376.f90 b/gcc/testsuite/gfortran.dg/PR82376.f90
new file mode 100644
index 00000000000..cea1c2ae211
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/PR82376.f90
@@ -0,0 +1,55 @@
+! { dg-do run }
+!
+! Test the fix for PR82376
+!
+
+program main_p
+
+  integer, parameter :: n = 10
+
+  type :: foo_t
+    integer, pointer :: v =>null()
+  end type foo_t
+
+  integer, save :: pcnt = 0
+  
+  type(foo_t) :: int
+  integer     :: i
+
+  do i = 1, n
+    call init(int, i)
+    if(.not.associated(int%v)) stop 1
+    if(int%v/=i) stop 2
+    if(pcnt/=i) stop 3
+  end do
+
+contains
+
+  function new(data) result(this)
+    integer, target, intent(in) :: data
+
+    integer, pointer :: this
+
+    nullify(this)
+    this => data
+    pcnt = pcnt + 1
+    return
+  end function new
+
+  subroutine init(this, data)
+    type(foo_t), intent(out) :: this
+    integer,     intent(in)  :: data
+
+    call set(this, new(data))
+    return
+  end subroutine init
+
+  subroutine set(this, that)
+    type(foo_t),     intent(inout) :: this
+    integer, target, intent(in)    :: that
+
+    this%v => that
+    return
+  end subroutine set
+  
+end program main_p

Re: [Patch, fortran] PR fortran/82376 - Duplicate function call using -fcheck=pointer

[Paul Richard Thomas]

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Hi José!

The fix is fine.

Note however that the testcase will pass even without the fix because you
haven't included the
! { dg-options "-fcheck=pointer" }.

In fact, I suggest that you use the version of the tescase that I have
attached that does not run but counts the number of occurrences of 'new' in
the tree dump.

OK for master, certainly for 11-branch, when it is open again, and for
10-branch after a wait.

Are you reliant on others to commit and push your patches or have you done
the FSF paperwork?

Thanks

Paul




On Thu, 22 Apr 2021 at 21:50, José Rui Faustino de Sousa via Fortran <
fortran@gcc.gnu.org> wrote:

> Hi All!
>
> Proposed patch to:
>
> PR82376 - Duplicate function call using -fcheck=pointer
>
> Patch tested only on x86_64-pc-linux-gnu.
>
> Evaluate function result and then pass a pointer, instead of a reference
> to the function itself, thus avoiding multiple evaluations of the function.
>
> Thank you very much.
>
> Best regards,
> José Rui
>
> Fortran: Fix double function call with -fcheck=pointer [PR]
>
> gcc/fortran/ChangeLog:
>
>         PR fortran/82376
>         * trans-expr.c (gfc_conv_procedure_call): Evaluate function result
>         and then pass a pointer.
>
> gcc/testsuite/ChangeLog:
>
>         PR fortran/82376
>         * gfortran.dg/PR82376.f90: New test.
>
>

-- 
"If you can't explain it simply, you don't understand it well enough" -
Albert Einstein

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! { dg-do compile }
! { dg-options "-fdump-tree-original -fcheck=pointer" }
!
! Test the fix for PR82376. The pointer check was doubling up the call
! to new. The fix reduces the count of 'new' from 5 to 4.
!
! Contributed by José Rui Faustino de Sousa  <jrfsousa@gmail.com>
!
program main_p

  integer, parameter :: n = 10

  type :: foo_t
    integer, pointer :: v =>null()
  end type foo_t

  integer, save :: pcnt = 0

  type(foo_t) :: int
  integer     :: i

  do i = 1, n
    call init(int, i)
    if(.not.associated(int%v)) stop 1
    if(int%v/=i) stop 2
    if(pcnt/=i) stop 3
  end do

contains

  function new(data) result(this)
    integer, target, intent(in) :: data

    integer, pointer :: this

    nullify(this)
    this => data
    pcnt = pcnt + 1
    return
  end function new

  subroutine init(this, data)
    type(foo_t), intent(out) :: this
    integer,     intent(in)  :: data

    call set(this, new(data))
    return
  end subroutine init

  subroutine set(this, that)
    type(foo_t),     intent(inout) :: this
    integer, target, intent(in)    :: that

    this%v => that
    return
  end subroutine set

end program main_p
! { dg-final { scan-tree-dump-times "new" 4 "original" } }