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Re: [PATCH, Fortran] -fno-automatic with -finit-local prevents initialization of automatics in recursive functions
- From: Tobias Burnus <burnus at net-b dot de>
- To: Fritz Reese <fritzoreese at gmail dot com>, fortran at gcc dot gnu dot org, gcc-patches at gcc dot gnu dot org
- Date: Mon, 01 Sep 2014 00:28:39 +0200
- Subject: Re: [PATCH, Fortran] -fno-automatic with -finit-local prevents initialization of automatics in recursive functions
- Authentication-results: sourceware.org; auth=none
- References: <CAE4aFAkSNjGYmpxUZtM8wSDYKvHaBxkpq2hX6sq8aqWfKndT+w at mail dot gmail dot com> <CAE4aFA=ubeZ3GTWmO-tUbDqrMiUTHfy7TOsexnh01Mb9poiQ_Q at mail dot gmail dot com>
Fritz Reese wrote:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62309
It seems with gcc-4.8.3 -fno-automatic prevents initializers from
being applied to automatic variables.
[...]
According to gfortran's manual page, -fno-automatic should "Treat each
program unit (except those marked as RECURSIVE) as if the "SAVE"
statement were specified for every local variable [...]". As far as I
can tell, -finit-local-zero should still initialize automatic
variables in RECURSIVE functions.
I believe this is a simple fix; to actually follow the specification
set forth in the man page, don't treat symbols in a RECURSIVE
namespace as if they are saved in resolve.c
(apply_default_init_local):
Thanks for the patch. I think it qualifies as obvious. But note for
potential future contributions that for nontrivial contributions a
copyright assignment with the FSF is required:
https://gcc.gnu.org/contribute.html
(Tiny nit: 8 spaces are replaced by a tab.)
I initially thought that one had to be more careful because of BLOCK,
but the RECURSIVE is passed on those namespaces, hence, the patch works
fine. I have extended the test case to cover that part as well.
I have now committed the attached version of the patch to the trunk (GCC
5) as Rev. 214771.
Tobias
(Side remark: I think it is bad style to rely on -finit-local with new
code - and RECURSIVE is new since Fortran 90) code.)
2014-08-29 Fritz Reese <Reese-Fritz@zai.com>
* resolve.c (apply_default_init_local): Don't treat variables in
RECURSIVE units as saved.
Index: gcc/fortran/ChangeLog
===================================================================
--- gcc/fortran/ChangeLog (Revision 214770)
+++ gcc/fortran/ChangeLog (Arbeitskopie)
@@ -1,3 +1,9 @@
+2014-08-31 Fritz Reese <Reese-Fritz@zai.com>
+
+ PR fortran/62309
+ * resolve.c (apply_default_init_local): Don't treat variables
+ in RECURSIVE procedures as saved.
+
2014-08-31 Tobias Burnus <burnus@net-b.de>
* trans-decl.c (gfc_build_builtin_function_decls): Add
Index: gcc/fortran/resolve.c
===================================================================
--- gcc/fortran/resolve.c (Revision 214770)
+++ gcc/fortran/resolve.c (Arbeitskopie)
@@ -10780,6 +10780,7 @@ apply_default_init_local (gfc_symbol *sym)
result variable, which are also nonstatic. */
if (sym->attr.save || sym->ns->save_all
|| (gfc_option.flag_max_stack_var_size == 0 && !sym->attr.result
+ && !sym->ns->proc_name->attr.recursive
&& (!sym->attr.dimension || !is_non_constant_shape_array (sym))))
{
/* Don't clobber an existing initializer! */
Index: gcc/testsuite/ChangeLog
===================================================================
--- gcc/testsuite/ChangeLog (Revision 214770)
+++ gcc/testsuite/ChangeLog (Arbeitskopie)
@@ -1,3 +1,9 @@
+2014-08-31 Fritz Reese <Reese-Fritz@zai.com>
+ Tobias Burnus <burnus@net-b.de>
+
+ PR fortran/62309
+ * gcc/testsuite/gfortran.dg/auto_save_2.f90: New.
+
2014-08-31 Tobias Burnus <burnus@net-b.de>
* gfortran.dg/coarray_lib_comm_1.f90: New.
Index: gcc/testsuite/gfortran.dg/auto_save_2.f90
===================================================================
--- gcc/testsuite/gfortran.dg/auto_save_2.f90 (Revision 0)
+++ gcc/testsuite/gfortran.dg/auto_save_2.f90 (Arbeitskopie)
@@ -0,0 +1,84 @@
+! { dg-do run }
+! { dg-options "-fno-automatic -finit-local-zero -fdump-tree-original" }
+!
+! PR fortran/62309
+!
+! Make sure variables are saved with -fno-automatic except in
+! functions marked RECURSIVE, and that they are still initialized with
+! -finit-local-zero.
+!
+
+function f (x)
+implicit none
+ integer f, x
+ integer a ! should be SAVEd
+ a = a + x ! should increment by y every time
+ f = a
+ return
+endfunction
+
+function f2 (x)
+implicit none
+ integer f2, x
+ block
+ named: block
+ block
+ integer a ! should be SAVEd
+ a = a + x ! should increment by y every time
+ f2 = a
+ end block
+ end block named
+ end block
+ return
+endfunction
+
+recursive function g (x)
+implicit none
+ integer g, x
+ integer b ! should be automatic
+ b = b + x ! should be set to y every time
+ g = b
+ return
+endfunction
+
+recursive function g2 (x)
+implicit none
+ integer g2, x
+ block
+ named: block
+ block
+ integer b ! should be automatic
+ b = b + x ! should be set to y every time
+ g2 = b
+ end block
+ end block named
+ end block
+ return
+endfunction
+
+implicit none
+integer f, f2, g, g2
+
+! Should return static value of a; accumulates y
+if ( f(3) .ne. 3 ) call abort ()
+if ( f(4) .ne. 7 ) call abort ()
+if ( f(2) .ne. 9 ) call abort ()
+
+if ( f2(3) .ne. 3 ) call abort ()
+if ( f2(4) .ne. 7 ) call abort ()
+if ( f2(2) .ne. 9 ) call abort ()
+
+! Should return automatic value of a; equal to y each time
+if ( g(3) .ne. 3 ) call abort ()
+if ( g(4) .ne. 4 ) call abort ()
+if ( g(2) .ne. 2 ) call abort ()
+
+if ( g2(3) .ne. 3 ) call abort ()
+if ( g2(4) .ne. 4 ) call abort ()
+if ( g2(2) .ne. 2 ) call abort ()
+
+end
+
+! { dg-final { scan-tree-dump-times " static integer\\\(kind=4\\\) a = 0;" 2 "original" } }
+! { dg-final { scan-tree-dump-times " b = 0;" 2 "original" } }
+! { dg-final { cleanup-tree-dump "original" } }