[Bug tree-optimization/19633] New: local address incorrectly thought to escape

[Bug tree-optimization/19633] New: local address incorrectly thought to escape

[rth at gcc dot gnu dot org]

struct S { int w, x, y, z; };
struct T { int r; struct S s; };
void bar (struct S, int);
void foo (int a, struct T b)
{
  struct S *c = 0;
  if (a)
    c = &b.s;
  bar (*c, a);
}


The call to bar appears to not be marked [tail-call] because b is marked
as a call-clobbered local variable.  Which IIRC means that the aliasing code
thinks that the address of b escapes.  Which is untrue -- no address escapes
from this function.

-- 
           Summary: local address incorrectly thought to escape
           Product: gcc
           Version: 4.0.0
            Status: UNCONFIRMED
          Keywords: missed-optimization
          Severity: enhancement
          Priority: P2
         Component: tree-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: rth at gcc dot gnu dot org
                CC: dnovillo at gcc dot gnu dot org,gcc-bugs at gcc dot gnu
                    dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19633

[Bug tree-optimization/19633] local address incorrectly thought to escape

[steven at gcc dot gnu dot org]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
OtherBugsDependingO|                            |19616
              nThis|                            |
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|                            |1
   Last reconfirmed|0000-00-00 00:00:00         |2005-01-25 23:26:49
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19633

[Bug tree-optimization/19633] local address incorrectly thought to escape

[steven at gcc dot gnu dot org]

------- Additional Comments From steven at gcc dot gnu dot org  2005-01-25 23:32 -------
;; Function foo (foo) 
 
Visiting use-def links for 0B 
Visiting use-def links for &bD.1128.sD.1123 
foo: Total number of aliased vops: 0 
 
Referenced variables in foo: 4 
 
Variable: cD.1131, UID 0, struct S *, type memory tag: TMT.0D.1138 
 
Variable: aD.1127, UID 1, intD.0, default def: aD.1127_3 
 
Variable: bD.1128, UID 2, struct T, is an alias tag, is addressable, call 
clobbered, default def: bD.1128_5 
 
Variable: TMT.0D.1138, UID 3, struct S, is addressable, is global, call 
clobbered, may aliases: { bD.1128 } 
 
 
Alias statistics for foo 
 
Total alias queries:    1 
Total alias mayalias results:   1 
Total alias noalias results:    0 
Total simple queries:   1 
Total simple resolved:  0 
Total TBAA queries:     1 
Total TBAA resolved:    0 
 

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19633

[Bug tree-optimization/19633] local address incorrectly thought to escape

[dnovillo at gcc dot gnu dot org]

------- Additional Comments From dnovillo at gcc dot gnu dot org  2005-01-26 23:34 -------

Testing patch.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |dnovillo at gcc dot gnu dot
                   |dot org                     |org
             Status|NEW                         |ASSIGNED


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19633

[Bug tree-optimization/19633] local address incorrectly thought to escape

[cvs-commit at gcc dot gnu dot org]

------- Additional Comments From cvs-commit at gcc dot gnu dot org  2005-01-27 04:45 -------
Subject: Bug 19633

CVSROOT:	/cvs/gcc
Module name:	gcc
Changes by:	dnovillo@gcc.gnu.org	2005-01-27 04:45:20

Modified files:
	gcc            : ChangeLog tree-outof-ssa.c tree-ssa-alias.c 
	gcc/testsuite  : ChangeLog 
Added files:
	gcc/testsuite/gcc.dg: pr19633.c 
	gcc/testsuite/gcc.dg/tree-ssa: pr19633.c 

Log message:
	PR tree-optimization/19633
	* tree-ssa-alias.c (ptr_is_dereferenced_by): Also handle
	CALL_EXPRs.
	(maybe_create_global_var): Do not create .GLOBAL_VAR if there
	are no call-clobbered variables.
	* tree-outof-ssa.c (check_replaceable): Return false for calls
	with side-effects.
	
	testsuite/ChangeLog
	
	PR tree-optimization/19633
	* gcc.dg/pr19633.c: New test.
	* gcc.dg/tree-ssa/pr19633.c: New test.

Patches:
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/ChangeLog.diff?cvsroot=gcc&r1=2.7297&r2=2.7298
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/tree-outof-ssa.c.diff?cvsroot=gcc&r1=2.41&r2=2.42
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/tree-ssa-alias.c.diff?cvsroot=gcc&r1=2.66&r2=2.67
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/ChangeLog.diff?cvsroot=gcc&r1=1.4940&r2=1.4941
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/gcc.dg/pr19633.c.diff?cvsroot=gcc&r1=NONE&r2=1.1
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/gcc.dg/tree-ssa/pr19633.c.diff?cvsroot=gcc&r1=NONE&r2=1.1



-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19633

[Bug tree-optimization/19633] local address incorrectly thought to escape

[dnovillo at gcc dot gnu dot org]

------- Additional Comments From dnovillo at gcc dot gnu dot org  2005-01-27 04:58 -------

Fix: http://gcc.gnu.org/ml/gcc-patches/2005-01/msg01969.html.

This does not completely get you the tail call you were looking for, but it does
address the address escaping problem.  I would probably just close it as we
already have PRs for the TREE_ADDRESSABLE arguments in the call.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |WAITING


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19633

[Bug tree-optimization/19633] local address incorrectly thought to escape

[steven at gcc dot gnu dot org]

------- Additional Comments From steven at gcc dot gnu dot org  2005-01-30 20:50 -------
I still see "b" marked as "call clobbered": 
 
struct S { int w, x, y, z; }; 
struct T { int r; struct S s; }; 
 
void bar(struct S, int); 
 
void foo(int a, struct T b) 
{ 
  struct S *c = 0; 
  if (a) 
    c = &b.s; 
  bar (*c, a); 
} 
 
 
--> .alias4 dump 
 
;; Function foo (foo) 
 
Visiting use-def links for 0B 
Visiting use-def links for &bD.1459.sD.1454 
foo: Total number of aliased vops: 1 
 
Referenced variables in foo: 4 
 
Variable: cD.1462, UID 0, struct S *, type memory tag: TMT.0D.1469 
 
Variable: aD.1458, UID 1, intD.0, default def: aD.1458_3 
 
Variable: bD.1459, UID 2, struct T, is an alias tag, is addressable, call 
clobbered, default def: bD.1459_5 
 
Variable: TMT.0D.1469, UID 3, struct S, is addressable, is global, call 
clobbered, may aliases: { bD.1459 } 
 
(...) 
 
Aliased symbols 
 
bD.1459, UID 2, struct T, is an alias tag, is addressable, call clobbered, 
default def: bD.1459_5 
TMT.0D.1469, UID 3, struct S, is addressable, is global, call clobbered, may 
aliases: { bD.1459 } 
 
Dereferenced pointers 
 
cD.1462, UID 0, struct S *, type memory tag: TMT.0D.1469 
 
Type memory tags 
 
TMT.0D.1469, UID 3, struct S, is addressable, is global, call clobbered, may 
aliases: { bD.1459 } 
 
(...) 
 
foo (aD.1458, bD.1459) 
{ 
  struct S * cD.1462; 
 
  # BLOCK 0 
  # PRED: ENTRY [100.0%]  (fallthru,exec) 
  if (aD.1458_3 != 0) goto <L0>; else goto <L1>; 
  # SUCC: 1 [67.0%]  (true,exec) 2 [33.0%]  (false,exec) 
 
  # BLOCK 1 
  # PRED: 0 [67.0%]  (true,exec) 
<L0>:; 
  # SUCC: 2 [100.0%]  (fallthru,exec) 
 
  # BLOCK 2 
  # PRED: 0 [33.0%]  (false,exec) 1 [100.0%]  (fallthru,exec) 
  # cD.1462_1 = PHI <0B(0), &bD.1459.sD.1454(1)>; 
<L1>:; 
  #   bD.1459_6 = V_MAY_DEF <bD.1459_5>; 
  bar (*cD.1462_1, aD.1458_3); 
  return; 
  # SUCC: EXIT [100.0%] 
 
} 
 

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19633

[Bug tree-optimization/19633] local address incorrectly thought to escape

[cvs-commit at gcc dot gnu dot org]

------- Additional Comments From cvs-commit at gcc dot gnu dot org  2005-02-01 20:30 -------
Subject: Bug 19633

CVSROOT:	/cvs/gcc
Module name:	gcc
Changes by:	dnovillo@gcc.gnu.org	2005-02-01 20:30:08

Modified files:
	gcc            : ChangeLog tree-flow.h tree-ssa-alias.c 
	gcc/testsuite  : ChangeLog 
	gcc/testsuite/gcc.dg: pr19633.c 
Added files:
	gcc/testsuite/gcc.dg: pr19633-1.c 

Log message:
	PR tree-optimization/19633
	* tree-flow.h (struct ptr_info_def): Add field 'pt_null'.
	* tree-ssa-alias.c (init_alias_info): Initialize.
	(merge_pointed_to_info): Set.
	(add_pointed_to_expr): Set pt_null if EXPR is a NULL pointer.
	(dump_points_to_info_for): Show value of pt_null.
	(struct count_ptr_d): Declare.
	(find_ptr_dereference): Remove.
	(ptr_is_dereferenced_by): Remove.
	(count_ptr_derefs): New local function.
	(count_uses_and_derefs): New local function.
	(compute_points_to_and_addr_escape): Call it.  If the number
	of dereferences is greater than zero, mark the pointer as
	dereferenced.  If there are fewer dereferences than uses of
	the pointer, the pointer's value escapes.
	
	testsuite/ChangeLog
	
	PR tree-optimization/19633
	* testsuite/gcc.dg/pr19633-1.c: New test.
	* testsuite/gcc.dg/pr19633.c: Tweak to make pointer point
	to NULL or a symbol.

Patches:
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/ChangeLog.diff?cvsroot=gcc&r1=2.7365&r2=2.7366
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/tree-flow.h.diff?cvsroot=gcc&r1=2.78&r2=2.79
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/tree-ssa-alias.c.diff?cvsroot=gcc&r1=2.67&r2=2.68
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/ChangeLog.diff?cvsroot=gcc&r1=1.4973&r2=1.4974
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/gcc.dg/pr19633-1.c.diff?cvsroot=gcc&r1=NONE&r2=1.1
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/gcc.dg/pr19633.c.diff?cvsroot=gcc&r1=1.1&r2=1.2



-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19633

[Bug tree-optimization/19633] local address incorrectly thought to escape

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2005-02-18 03:22 -------
Hmm, the testcase now fails on ppc-darwin.

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19633

[Bug tree-optimization/19633] local address incorrectly thought to escape

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2005-05-21 12:52 -------
Should this be closed?

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19633

[Bug tree-optimization/19633] local address incorrectly thought to escape

[steven at gcc dot gnu dot org]

------- Additional Comments From steven at gcc dot gnu dot org  2005-06-13 13:41 -------
 
Ping Diego, should this be closed?? 

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19633

[Bug tree-optimization/19633] local address incorrectly thought to escape

[dnovillo at redhat dot com]

------- Additional Comments From dnovillo at redhat dot com  2005-06-13 13:44 -------
Subject: Re:  local address incorrectly thought to escape

On Mon, Jun 13, 2005 at 01:41:06PM -0000, steven at gcc dot gnu dot org wrote:

> Ping Diego, should this be closed?? 
> 
If the testcase now works on ppc-darwin (see comment #7), then
yes.


Diego.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19633

[Bug tree-optimization/19633] local address incorrectly thought to escape

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2005-06-13 13:47 -------
(In reply to comment #10)
> If the testcase now works on ppc-darwin (see comment #7), then
> yes.

Yes it does.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|WAITING                     |RESOLVED
         Resolution|                            |FIXED


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19633

[Bug tree-optimization/19633] local address incorrectly thought to escape

[pinskia at gcc dot gnu dot org]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |4.0.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19633

[Bug tree-optimization/19633] local address incorrectly thought to escape

[brett dot albertson at stratech dot com]

------- Comment #12 from brett dot albertson at stratech dot com  2006-12-14 12:55 -------
This testcase started failing for me as of last night on trunk.

1c1
< Test Run By root on Thu Dec 14 06:04:39 2006
---
> Test Run By root on Wed Dec 13 06:04:24 2006
....  cut for space saving .....

30945,30946c30909,30910
< FAIL: gcc.dg/pr19633-1.c (test for excess errors)
< WARNING: gcc.dg/pr19633-1.c compilation failed to produce executable
---
> PASS: gcc.dg/pr19633-1.c (test for excess errors)
> PASS: gcc.dg/pr19633-1.c execution test
39056d39019
< PASS: gcc.dg/tls/opt-13.c (test for excess errors)
42919,42920c42882,42883
< # of expected passes          42352
< # of unexpected failures      12
---
> # of expected passes		42317
> # of unexpected failures	11
42926c42889
< /u01/var/tmp/gcc_trunk_svn/gcc_20061214/gcc/xgcc  version 4.3.0 20061214
(experimental)
---
> /u01/var/tmp/gcc_trunk_svn/gcc_20061213/gcc/xgcc  version 4.3.0 20061213 (experimental)

I run on Solaris 10 x86.  I can provide more information as needed.

Brett Albertson


-- 

brett dot albertson at stratech dot com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |brett dot albertson at
                   |                            |stratech dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19633