[gcc r13-2838] fortran: Support clobbering of SAVE variables [PR41453]

[Mikael Morin <mikael@gcc.gnu.org>]

https://gcc.gnu.org/g:467ef2c40dbaf9d1219d9642e90df77dc61f4fae

commit r13-2838-g467ef2c40dbaf9d1219d9642e90df77dc61f4fae
Author: Mikael Morin <mikael@gcc.gnu.org>
Date:   Wed Aug 31 11:54:47 2022 +0200

    fortran: Support clobbering of SAVE variables [PR41453]
    
    This removes a condition added in:
    r9-3032-gee7fb0588c6361b4d77337ab0f7527be64fcdde2.
    
    That commit added a condition to avoid generating ICE with clobbers
    of variables with the SAVE attribute.
    The test added at that point continues to pass if we remove that
    condition now.
    
            PR fortran/41453
            PR fortran/87395
    
    gcc/fortran/ChangeLog:
    
            * trans-expr.cc (gfc_conv_procedure_call): Remove condition
            on SAVE attribute guarding clobber generation.
    
    gcc/testsuite/ChangeLog:
    
            * gfortran.dg/intent_optimize_7.f90: New test.

Diff:
---
 gcc/fortran/trans-expr.cc                       |  2 --
 gcc/testsuite/gfortran.dg/intent_optimize_7.f90 | 45 +++++++++++++++++++++++++
 2 files changed, 45 insertions(+), 2 deletions(-)

diff --git a/gcc/fortran/trans-expr.cc b/gcc/fortran/trans-expr.cc
index 11b7c05929c..10b49347587 100644
--- a/gcc/fortran/trans-expr.cc
+++ b/gcc/fortran/trans-expr.cc
@@ -6527,8 +6527,6 @@ gfc_conv_procedure_call (gfc_se * se, gfc_symbol * sym,
 			  && !e->symtree->n.sym->attr.dimension
 			  && !e->symtree->n.sym->attr.pointer
 			  && !e->symtree->n.sym->attr.allocatable
-			  /* FIXME - PR 87395 and PR 41453  */
-			  && e->symtree->n.sym->attr.save == SAVE_NONE
 			  && !e->symtree->n.sym->attr.associate_var
 			  && e->ts.type != BT_CHARACTER
 			  && e->ts.type != BT_DERIVED
diff --git a/gcc/testsuite/gfortran.dg/intent_optimize_7.f90 b/gcc/testsuite/gfortran.dg/intent_optimize_7.f90
new file mode 100644
index 00000000000..c2f21929863
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/intent_optimize_7.f90
@@ -0,0 +1,45 @@
+! { 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 SAVE variables.
+
+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 :: c = 0
+
+  ! implicit SAVE attribute
+  c = 123456789
+  call foo(c)
+  if (c /= 42) stop 1
+
+  ! explicit SAVE attribute
+  call check_save_explicit
+
+contains
+  subroutine check_save_explicit
+    integer, save :: d
+    d = 987654321
+    call foo(d)
+    if (d /= 42) stop 2
+  end subroutine check_save_explicit
+end program main
+
+! { dg-final { scan-tree-dump-times "CLOBBER" 2 "original" } }
+! { dg-final { scan-tree-dump "c = {CLOBBER};" "original" } }
+! { dg-final { scan-tree-dump "d = {CLOBBER};" "original" } }
+! { dg-final { scan-tree-dump-not "123456789" "optimized" { target __OPTIMIZE__ } } }
+! { dg-final { scan-tree-dump-not "987654321" "optimized" { target __OPTIMIZE__ } } }