[gcc r13-2840] fortran: Support clobbering of allocatables and pointers [PR41453]

[gcc r13-2840] fortran: Support clobbering of allocatables and pointers [PR41453]

[Mikael Morin]

https://gcc.gnu.org/g:95375ffb3dd59f51e79408dd3b2b620dc1af71b1

commit r13-2840-g95375ffb3dd59f51e79408dd3b2b620dc1af71b1
Author: Mikael Morin <mikael@gcc.gnu.org>
Date:   Thu Sep 1 11:27:36 2022 +0200

    fortran: Support clobbering of allocatables and pointers [PR41453]
    
    This adds support for clobbering of allocatable and pointer scalar
    variables passed as actual argument to a subroutine when the associated
    dummy has the INTENT(OUT) attribute.
    Support was explicitly disabled (since the beginning for pointers, since
    r11-7315-g2df374b337a5f6cf5528e91718e4e12e4006b7ae for allocatables),
    but the clobber generation code seems to support it well, as
    demonstrated by the newly added testcase.
    
            PR fortran/41453
            PR fortran/99169
    
    gcc/fortran/ChangeLog:
    
            * trans-expr.cc (gfc_conv_procedure_call): Remove conditions
            on ALLOCATABLE and POINTER attributes guarding clobber
            generation.
    
    gcc/testsuite/ChangeLog:
    
            * gfortran.dg/intent_optimize_9.f90: New test.

Diff:
---
 gcc/fortran/trans-expr.cc                       |  2 --
 gcc/testsuite/gfortran.dg/intent_optimize_9.f90 | 42 +++++++++++++++++++++++++
 2 files changed, 42 insertions(+), 2 deletions(-)

diff --git a/gcc/fortran/trans-expr.cc b/gcc/fortran/trans-expr.cc
index c2c7382c7d7..52b96fa6cf6 100644
--- a/gcc/fortran/trans-expr.cc
+++ b/gcc/fortran/trans-expr.cc
@@ -6525,8 +6525,6 @@ gfc_conv_procedure_call (gfc_se * se, gfc_symbol * sym,
 			  && e->symtree
 			  && e->symtree->n.sym
 			  && !e->symtree->n.sym->attr.dimension
-			  && !e->symtree->n.sym->attr.pointer
-			  && !e->symtree->n.sym->attr.allocatable
 			  && e->ts.type != BT_CHARACTER
 			  && e->ts.type != BT_DERIVED
 			  && e->ts.type != BT_CLASS
diff --git a/gcc/testsuite/gfortran.dg/intent_optimize_9.f90 b/gcc/testsuite/gfortran.dg/intent_optimize_9.f90
new file mode 100644
index 00000000000..0146dff4e20
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/intent_optimize_9.f90
@@ -0,0 +1,42 @@
+! { dg-do run }
+! { dg-additional-options "-fno-inline -fno-ipa-modref -fdump-tree-optimized -fdump-tree-original" }
+!
+! PR fortran/41453
+! Check that the INTENT(OUT) attribute causes one clobber to be emitted in
+! the caller before each call to FOO in the *.original dump, and the
+! initialization constants to be optimized away in the *.optimized dump,
+! in the case of scalar allocatables and pointers.
+
+module x
+implicit none
+contains
+  subroutine foo(a)
+    integer, intent(out) :: a
+    a = 42
+  end subroutine foo
+end module x
+
+program main
+  use x
+  implicit none
+  integer, allocatable :: ca
+  integer, target :: ct
+  integer, pointer :: cp
+
+  allocate(ca)
+  ca = 123456789
+  call foo(ca)
+  if (ca /= 42) stop 1
+  deallocate(ca)
+
+  ct = 987654321
+  cp => ct
+  call foo(cp)
+  if (ct /= 42) stop 2
+end program main
+
+! { dg-final { scan-tree-dump-times "CLOBBER" 2 "original" } }
+! { dg-final { scan-tree-dump "\\*ca = {CLOBBER};" "original" } }
+! { dg-final { scan-tree-dump "\\*cp = {CLOBBER};" "original" } }
+! { dg-final { scan-tree-dump-not "123456789" "optimized" { target __OPTIMIZE__ } } }
+! { dg-final { scan-tree-dump-not "987654321" "optimized" { target __OPTIMIZE__ } } }