[Patch, fortran] Fix PR59345, repacking of a packed temporary array

[Patch, fortran] Fix PR59345, repacking of a packed temporary array

[Thomas Koenig]

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Hello world,

the attached patch fixes a rather bad missed optimization, where
the generated temporary array for

SUBROUTINE S1(A)
  REAL :: A(3)
  CALL S2(-A)
END SUBROUTINE


was packed and unpacked(!).

Regression-tested. OK for trunk?

Regards

	Thomas

2019-01-10  Thomas Koenig  <tkoenig@gcc.gnu.org>

         PR fortran/59345
         * trans-array.c (gfc_conv_parameter_array):  Temporary
         arrays generated for expressions do not need to be repacked.

2019-01-10  Thomas Koenig  <tkoenig@gcc.gnu.org>

         PR fortran/59345
         * gfortran.dg/internal_pack_16.f90: New test.

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Index: trans-array.c
===================================================================
--- trans-array.c	(Revision 267737)
+++ trans-array.c	(Arbeitskopie)
@@ -7866,6 +7866,12 @@ gfc_conv_array_parameter (gfc_se * se, gfc_expr *
 
   no_pack = contiguous && no_pack;
 
+  /* If we have an expression, an array temporary will be
+     generated which does not need to be packed / unpacked
+     if passed to an explicit-shape dummy array.  */
+
+  no_pack = no_pack || (g77 && expr->expr_type == EXPR_OP);
+
   /* Array constructors are always contiguous and do not need packing.  */
   array_constructor = g77 && !this_array_result && expr->expr_type == EXPR_ARRAY;
 

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! { dg-do compile }
! { dg-additional-options "-fdump-tree-original" }
! PR 59345 - pack/unpack was not needed here.
SUBROUTINE S1(A)
 REAL :: A(3)
 CALL S2(-A)
END SUBROUTINE
! { dg-final { scan-tree-dump-not "_gfortran_internal_pack" "original" } }
! { dg-final { scan-tree-dump-not "_gfortran_internal_unpack" "original" } }

Re: [Patch, fortran] Fix PR59345, repacking of a packed temporary array

[Steve Kargl]

On Thu, Jan 10, 2019 at 09:17:37PM +0100, Thomas Koenig wrote:
> 
> the attached patch fixes a rather bad missed optimization, where
> the generated temporary array for
> 
> SUBROUTINE S1(A)
>   REAL :: A(3)
>   CALL S2(-A)
> END SUBROUTINE
> 
> was packed and unpacked(!).
> 
> Regression-tested. OK for trunk?
> 

Yes.

-- 
Steve