public inbox for gcc-bugs@sourceware.org
help / color / mirror / Atom feed
* [Bug c++/14531] New: pessimise code, loose constantness
@ 2004-03-11 12:47 smelkov at mph1 dot phys dot spbu dot ru
2004-03-11 12:49 ` [Bug c++/14531] " smelkov at mph1 dot phys dot spbu dot ru
` (5 more replies)
0 siblings, 6 replies; 7+ messages in thread
From: smelkov at mph1 dot phys dot spbu dot ru @ 2004-03-11 12:47 UTC (permalink / raw)
To: gcc-bugs
I've found some case, where g++ fails to recognize an expression as compile time const
(ok, it recognizes it, but delays initialization till program run)
Here is the case source with g++ and icc8 assember output. Just look on how subidx_rmap is
initialized.
--- const_array.cpp ---
//! calculates offset of (unambigous, non-virtual) BASE in CHILD
//! @param TYPE class inhereted from BASE
//! @param BASE the base class for TYPE
//! @note it looks like C++ mandates NULL pointer to be always casted to NULL, hence i
//! use 0x1000 here.
#define base_delta(TYPE, BASE) ( (signed long)((static_cast<BASE*>(
reinterpret_cast<TYPE*>(0x1000UL) ))) - 0x1000 )
struct A
{
int a;
};
struct B
{
int b;
};
struct C : public A, public B
{
};
const signed long subidx_rmap[] =
{
base_delta(C, B),
33,
137
};
---------------------------------
---const_array.s.g++----
.file "const_array.cpp"
.local subidx_rmap
.comm subidx_rmap,12,4
.text
.align 2
.type __static_initialization_and_destruction_0(int, int), @function
__static_initialization_and_destruction_0(int, int):
.LFB3:
pushl %ebp
.LCFI0:
movl %esp, %ebp
.LCFI1:
cmpl $65535, 12(%ebp)
jne .L1
cmpl $1, 8(%ebp)
jne .L1
movl $4, %eax
movl %eax, subidx_rmap
movl $33, subidx_rmap+4
movl $137, subidx_rmap+8
.L1:
popl %ebp
ret
.LFE3:
.size __static_initialization_and_destruction_0(int, int),
.-__static_initialization_and_destruction_0(int, int)
.align 2
.type _GLOBAL__I_const_array.cppG85Xva, @function
_GLOBAL__I_const_array.cppG85Xva:
.LFB5:
pushl %ebp
.LCFI2:
movl %esp, %ebp
.LCFI3:
subl $8, %esp
.LCFI4:
movl $65535, 4(%esp)
movl $1, (%esp)
call __static_initialization_and_destruction_0(int, int)
leave
ret
.LFE5:
.size _GLOBAL__I_const_array.cppG85Xva, .-_GLOBAL__I_const_array.cppG85Xva
.section .ctors,"aw",@progbits
.align 4
.long _GLOBAL__I_const_array.cppG85Xva
.section .note.GNU-stack,"",@progbits
.ident "GCC: (GNU) 3.3.3"
--------------------------------
---const_array.s.icc---
# -- Machine type IA32
# mark_description "Intel(R) C++ Compiler for 32-bit applications, Version 8.0 Build
20031016Z %s";
# mark_description "-long_double -Wall -S -o const_array.s.icc";
.ident "Intel(R) C++ Compiler for 32-bit applications, Version 8.0 Build 20031016Z %s"
.ident "-long_double -Wall -S -o const_array.s.icc"
.file "const_array.cpp"
.text
.data
.align 4
.bss
.align 4
.section .rodata, "a"
.align 4
.section .data1, "wa"
.align 4
.section .text1, "wa"
.align 4
.section .rodata, "a"
.align 4
subidx_rmap:
.long 4 # s32
.long 33 # s32
.long 137 # s32
.type subidx_rmap,@object
.size subidx_rmap,12
.data
.section .text
.LNDBG_TXe:
# End
---------------------------------
g++ info:
[kirr@tugrik test]$ g++ -v
Reading specs from /usr/local/gcc-3.3.3/lib/gcc-lib/i686-pc-linux-gnu/3.3.3/specs
Configured with: ../gcc-3.3.3/configure --prefix=/usr/local/gcc-3.3.3 --enable-threads=posix
--enable-languages=c,c++,f77 --enable-checking --disable-nls
Thread model: posix
gcc version 3.3.3
--
Summary: pessimise code, loose constantness
Product: gcc
Version: 3.3.3
Status: UNCONFIRMED
Severity: normal
Priority: P2
Component: c++
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: smelkov at mph1 dot phys dot spbu dot ru
CC: gcc-bugs at gcc dot gnu dot org
GCC build triplet: i686-pc-linux-gnu
GCC host triplet: i686-pc-linux-gnu
GCC target triplet: i686-pc-linux-gnu
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14531
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug c++/14531] pessimise code, loose constantness
2004-03-11 12:47 [Bug c++/14531] New: pessimise code, loose constantness smelkov at mph1 dot phys dot spbu dot ru
@ 2004-03-11 12:49 ` smelkov at mph1 dot phys dot spbu dot ru
2004-03-11 15:55 ` [Bug middle-end/14531] " pinskia at gcc dot gnu dot org
` (4 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: smelkov at mph1 dot phys dot spbu dot ru @ 2004-03-11 12:49 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From smelkov at mph1 dot phys dot spbu dot ru 2004-03-11 12:49 -------
Just to note: turning optimization on changes nothing.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14531
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug middle-end/14531] pessimise code, loose constantness
2004-03-11 12:47 [Bug c++/14531] New: pessimise code, loose constantness smelkov at mph1 dot phys dot spbu dot ru
2004-03-11 12:49 ` [Bug c++/14531] " smelkov at mph1 dot phys dot spbu dot ru
@ 2004-03-11 15:55 ` pinskia at gcc dot gnu dot org
2004-04-19 22:50 ` pinskia at gcc dot gnu dot org
` (3 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2004-03-11 15:55 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From pinskia at gcc dot gnu dot org 2004-03-11 15:55 -------
Confirmed.
Looks like this tree is not folded:
4096u == 0 ? -0x00000000000001000l : 4l;
--
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Component|c++ |middle-end
Ever Confirmed| |1
Keywords| |pessimizes-code
Last reconfirmed|0000-00-00 00:00:00 |2004-03-11 15:55:39
date| |
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14531
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug middle-end/14531] pessimise code, loose constantness
2004-03-11 12:47 [Bug c++/14531] New: pessimise code, loose constantness smelkov at mph1 dot phys dot spbu dot ru
2004-03-11 12:49 ` [Bug c++/14531] " smelkov at mph1 dot phys dot spbu dot ru
2004-03-11 15:55 ` [Bug middle-end/14531] " pinskia at gcc dot gnu dot org
@ 2004-04-19 22:50 ` pinskia at gcc dot gnu dot org
2004-04-20 4:33 ` cvs-commit at gcc dot gnu dot org
` (2 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2004-04-19 22:50 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From pinskia at gcc dot gnu dot org 2004-04-19 19:37 -------
Patch here: <http://gcc.gnu.org/ml/gcc-patches/2004-04/msg01185.html>.
--
What |Removed |Added
----------------------------------------------------------------------------
Keywords| |patch
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14531
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug middle-end/14531] pessimise code, loose constantness
2004-03-11 12:47 [Bug c++/14531] New: pessimise code, loose constantness smelkov at mph1 dot phys dot spbu dot ru
` (2 preceding siblings ...)
2004-04-19 22:50 ` pinskia at gcc dot gnu dot org
@ 2004-04-20 4:33 ` cvs-commit at gcc dot gnu dot org
2004-04-20 5:26 ` pinskia at gcc dot gnu dot org
2004-04-20 9:09 ` giovannibajo at libero dot it
5 siblings, 0 replies; 7+ messages in thread
From: cvs-commit at gcc dot gnu dot org @ 2004-04-20 4:33 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From cvs-commit at gcc dot gnu dot org 2004-04-20 02:52 -------
Subject: Bug 14531
CVSROOT: /cvs/gcc
Module name: gcc
Changes by: sayle@gcc.gnu.org 2004-04-20 02:52:18
Modified files:
gcc/cp : ChangeLog class.c
Log message:
PR middle-end/14531
* class.c (build_base_path): Call fold whilst building the NULL
pointer check expression trees.
Patches:
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/cp/ChangeLog.diff?cvsroot=gcc&r1=1.4034&r2=1.4035
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/cp/class.c.diff?cvsroot=gcc&r1=1.606&r2=1.607
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14531
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug middle-end/14531] pessimise code, loose constantness
2004-03-11 12:47 [Bug c++/14531] New: pessimise code, loose constantness smelkov at mph1 dot phys dot spbu dot ru
` (3 preceding siblings ...)
2004-04-20 4:33 ` cvs-commit at gcc dot gnu dot org
@ 2004-04-20 5:26 ` pinskia at gcc dot gnu dot org
2004-04-20 9:09 ` giovannibajo at libero dot it
5 siblings, 0 replies; 7+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2004-04-20 5:26 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From pinskia at gcc dot gnu dot org 2004-04-20 03:01 -------
Fixed on the mainline for 3.5.0.
--
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |RESOLVED
Resolution| |FIXED
Target Milestone|--- |3.5.0
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14531
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug middle-end/14531] pessimise code, loose constantness
2004-03-11 12:47 [Bug c++/14531] New: pessimise code, loose constantness smelkov at mph1 dot phys dot spbu dot ru
` (4 preceding siblings ...)
2004-04-20 5:26 ` pinskia at gcc dot gnu dot org
@ 2004-04-20 9:09 ` giovannibajo at libero dot it
5 siblings, 0 replies; 7+ messages in thread
From: giovannibajo at libero dot it @ 2004-04-20 9:09 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From giovannibajo at libero dot it 2004-04-20 07:45 -------
Roger, you didn't commit a testcase for this bug.
--
What |Removed |Added
----------------------------------------------------------------------------
CC| |sayle at gcc dot gnu dot
| |org, giovannibajo at libero
| |dot it
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14531
^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2004-04-20 7:45 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2004-03-11 12:47 [Bug c++/14531] New: pessimise code, loose constantness smelkov at mph1 dot phys dot spbu dot ru
2004-03-11 12:49 ` [Bug c++/14531] " smelkov at mph1 dot phys dot spbu dot ru
2004-03-11 15:55 ` [Bug middle-end/14531] " pinskia at gcc dot gnu dot org
2004-04-19 22:50 ` pinskia at gcc dot gnu dot org
2004-04-20 4:33 ` cvs-commit at gcc dot gnu dot org
2004-04-20 5:26 ` pinskia at gcc dot gnu dot org
2004-04-20 9:09 ` giovannibajo at libero dot it
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).