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* [Bug tree-optimization/36347] New: points-to sets should be always kept for call-clobbering
@ 2008-05-27 13:42 rguenth at gcc dot gnu dot org
2008-05-28 8:58 ` [Bug tree-optimization/36347] " rguenth at gcc dot gnu dot org
` (3 more replies)
0 siblings, 4 replies; 5+ messages in thread
From: rguenth at gcc dot gnu dot org @ 2008-05-27 13:42 UTC (permalink / raw)
To: gcc-bugs
typedef unsigned long my_uintptr_t;
int check_a(my_uintptr_t tagged_ptr);
int __attribute__((noinline)) try_a(my_uintptr_t x)
{
my_uintptr_t heap[2];
my_uintptr_t *hp = heap;
hp[0] = x;
hp[1] = 0;
return check_a((my_uintptr_t)(void*)((char*)hp + 1));
}
<bb 2>:
# heap_10 = VDEF <heap_9(D)>
heap[0] = x_2(D);
# heap_11 = VDEF <heap_10>
heap[1] = 0;
D.1562_4 = &heap + 1;
D.1563_5 = (long unsigned int) D.1562_4;
# heap_12 = VDEF <heap_11>
D.1561_6 = check_a (D.1563_5);
return D.1561_6;
The points-to solution for D.1562_4 is D.1562_4 = { heap }, but we drop
that to
D.1562_4, its value escapes, points-to anything
because the pointer is never dereferenced. This causes all addressable
variables to escape at the call to check_a, which pessimizes code and
causes useless VOPs.
--
Summary: points-to sets should be always kept for call-clobbering
Product: gcc
Version: 4.4.0
Status: UNCONFIRMED
Keywords: missed-optimization, alias
Severity: enhancement
Priority: P3
Component: tree-optimization
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: rguenth at gcc dot gnu dot org
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36347
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug tree-optimization/36347] points-to sets should be always kept for call-clobbering
2008-05-27 13:42 [Bug tree-optimization/36347] New: points-to sets should be always kept for call-clobbering rguenth at gcc dot gnu dot org
@ 2008-05-28 8:58 ` rguenth at gcc dot gnu dot org
2008-05-29 10:33 ` rguenth at gcc dot gnu dot org
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: rguenth at gcc dot gnu dot org @ 2008-05-28 8:58 UTC (permalink / raw)
To: gcc-bugs
------- Comment #1 from rguenth at gcc dot gnu dot org 2008-05-28 08:58 -------
I have a fix (fixing PR36346 fixes this as well).
--
rguenth at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
BugsThisDependsOn| |36346
AssignedTo|unassigned at gcc dot gnu |rguenth at gcc dot gnu dot
|dot org |org
Status|UNCONFIRMED |ASSIGNED
Ever Confirmed|0 |1
Last reconfirmed|0000-00-00 00:00:00 |2008-05-28 08:58:13
date| |
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36347
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug tree-optimization/36347] points-to sets should be always kept for call-clobbering
2008-05-27 13:42 [Bug tree-optimization/36347] New: points-to sets should be always kept for call-clobbering rguenth at gcc dot gnu dot org
2008-05-28 8:58 ` [Bug tree-optimization/36347] " rguenth at gcc dot gnu dot org
@ 2008-05-29 10:33 ` rguenth at gcc dot gnu dot org
2008-05-29 10:33 ` rguenth at gcc dot gnu dot org
2008-05-30 19:53 ` rguenth at gcc dot gnu dot org
3 siblings, 0 replies; 5+ messages in thread
From: rguenth at gcc dot gnu dot org @ 2008-05-29 10:33 UTC (permalink / raw)
To: gcc-bugs
------- Comment #2 from rguenth at gcc dot gnu dot org 2008-05-29 10:32 -------
Fixed.
--
rguenth at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Target Milestone|--- |4.4.0
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36347
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug tree-optimization/36347] points-to sets should be always kept for call-clobbering
2008-05-27 13:42 [Bug tree-optimization/36347] New: points-to sets should be always kept for call-clobbering rguenth at gcc dot gnu dot org
2008-05-28 8:58 ` [Bug tree-optimization/36347] " rguenth at gcc dot gnu dot org
2008-05-29 10:33 ` rguenth at gcc dot gnu dot org
@ 2008-05-29 10:33 ` rguenth at gcc dot gnu dot org
2008-05-30 19:53 ` rguenth at gcc dot gnu dot org
3 siblings, 0 replies; 5+ messages in thread
From: rguenth at gcc dot gnu dot org @ 2008-05-29 10:33 UTC (permalink / raw)
To: gcc-bugs
------- Comment #3 from rguenth at gcc dot gnu dot org 2008-05-29 10:32 -------
Subject: Bug 36347
Author: rguenth
Date: Thu May 29 10:31:58 2008
New Revision: 136152
URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=136152
Log:
2008-05-29 Richard Guenther <rguenther@suse.de>
PR tree-optimization/36343
PR tree-optimization/36346
PR tree-optimization/36347
* tree-flow.h (clobber_what_p_points_to): Declare.
* tree-ssa-structalias.c (set_uids_in_ptset): Whether the
pointed-to variable is dereferenced is irrelevant to whether
the pointer can access the pointed-to variable.
(clobber_what_p_points_to): New function.
* tree-ssa-alias.c (set_initial_properties): Use it.
* tree-ssa.c (verify_flow_sensitive_alias_info): Adjust
call clobber check for NMTs.
* gcc.c-torture/execute/pr36343.c: New testcase.
Added:
trunk/gcc/testsuite/gcc.c-torture/execute/pr36343.c
Modified:
trunk/gcc/ChangeLog
trunk/gcc/testsuite/ChangeLog
trunk/gcc/tree-flow.h
trunk/gcc/tree-ssa-alias.c
trunk/gcc/tree-ssa-structalias.c
trunk/gcc/tree-ssa.c
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36347
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug tree-optimization/36347] points-to sets should be always kept for call-clobbering
2008-05-27 13:42 [Bug tree-optimization/36347] New: points-to sets should be always kept for call-clobbering rguenth at gcc dot gnu dot org
` (2 preceding siblings ...)
2008-05-29 10:33 ` rguenth at gcc dot gnu dot org
@ 2008-05-30 19:53 ` rguenth at gcc dot gnu dot org
3 siblings, 0 replies; 5+ messages in thread
From: rguenth at gcc dot gnu dot org @ 2008-05-30 19:53 UTC (permalink / raw)
To: gcc-bugs
------- Comment #4 from rguenth at gcc dot gnu dot org 2008-05-30 19:52 -------
Fixed.
--
rguenth at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|ASSIGNED |RESOLVED
Resolution| |FIXED
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36347
^ permalink raw reply [flat|nested] 5+ messages in thread
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2008-05-27 13:42 [Bug tree-optimization/36347] New: points-to sets should be always kept for call-clobbering rguenth at gcc dot gnu dot org
2008-05-28 8:58 ` [Bug tree-optimization/36347] " rguenth at gcc dot gnu dot org
2008-05-29 10:33 ` rguenth at gcc dot gnu dot org
2008-05-29 10:33 ` rguenth at gcc dot gnu dot org
2008-05-30 19:53 ` rguenth at gcc dot gnu dot org
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