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* [Bug c/32244] New: bit-field: optimization BUG
@ 2007-06-07 13:36 s__nakayama at infoseek dot jp
2007-06-08 10:28 ` [Bug middle-end/32244] " rguenth at gcc dot gnu dot org
` (5 more replies)
0 siblings, 6 replies; 7+ messages in thread
From: s__nakayama at infoseek dot jp @ 2007-06-07 13:36 UTC (permalink / raw)
To: gcc-bugs
The output is different by the optimization.
testcase:
#include <stdio.h>
struct foo
{
unsigned long long b:33;
};
int main()
{
struct foo x = {2};
printf("%llx\n",(x.b<<32));
return 0;
}
result:
$ gcc bit.c -o bit; ./bit
200000000
$ gcc -O bit.c -o bit; ./bit
0
--
Summary: bit-field: optimization BUG
Product: gcc
Version: 4.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: s__nakayama at infoseek dot jp
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32244
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug middle-end/32244] bit-field: optimization BUG
2007-06-07 13:36 [Bug c/32244] New: bit-field: optimization BUG s__nakayama at infoseek dot jp
@ 2007-06-08 10:28 ` rguenth at gcc dot gnu dot org
2007-12-11 13:55 ` rguenth at gcc dot gnu dot org
` (4 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: rguenth at gcc dot gnu dot org @ 2007-06-08 10:28 UTC (permalink / raw)
To: gcc-bugs
------- Comment #1 from rguenth at gcc dot gnu dot org 2007-06-08 10:28 -------
Confirmed. We are wrongly expanding
;; D.2027 = D.2026 << 32
(insn 18 17 0 (parallel [
(set (reg:DI 59 [ D.2027 ])
(ashift:DI (reg:DI 60 [ D.2026 ])
(const_int 32 [0x20])))
(clobber (reg:CC 17 flags))
]) -1 (nil)
(nil))
without properly truncating the result to 33 bit precision.
Not a regression.
--
rguenth at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |rguenth at gcc dot gnu dot
| |org
Status|UNCONFIRMED |NEW
Component|c |middle-end
Ever Confirmed|0 |1
Keywords| |wrong-code
Known to fail| |2.95.4 4.1.2 4.2.0
Last reconfirmed|0000-00-00 00:00:00 |2007-06-08 10:28:26
date| |
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32244
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug middle-end/32244] bit-field: optimization BUG
2007-06-07 13:36 [Bug c/32244] New: bit-field: optimization BUG s__nakayama at infoseek dot jp
2007-06-08 10:28 ` [Bug middle-end/32244] " rguenth at gcc dot gnu dot org
@ 2007-12-11 13:55 ` rguenth at gcc dot gnu dot org
2008-01-25 14:21 ` rguenth at gcc dot gnu dot org
` (3 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: rguenth at gcc dot gnu dot org @ 2007-12-11 13:55 UTC (permalink / raw)
To: gcc-bugs
------- Comment #2 from rguenth at gcc dot gnu dot org 2007-12-11 13:54 -------
Very similar (apart from typeof) to PR30332.
--
rguenth at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
BugsThisDependsOn| |30332
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32244
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug middle-end/32244] bit-field: optimization BUG
2007-06-07 13:36 [Bug c/32244] New: bit-field: optimization BUG s__nakayama at infoseek dot jp
2007-06-08 10:28 ` [Bug middle-end/32244] " rguenth at gcc dot gnu dot org
2007-12-11 13:55 ` rguenth at gcc dot gnu dot org
@ 2008-01-25 14:21 ` rguenth at gcc dot gnu dot org
2008-01-25 15:36 ` rguenth at gcc dot gnu dot org
` (2 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: rguenth at gcc dot gnu dot org @ 2008-01-25 14:21 UTC (permalink / raw)
To: gcc-bugs
------- Comment #3 from rguenth at gcc dot gnu dot org 2008-01-25 13:23 -------
Uh, all is broken ;)
1) we don't reduce shift or rotate results
2) we do wrong folding of rotates
3) we do wrong expansion of rotates
struct foo
{
unsigned long long b:40;
} x;
extern void abort (void);
void test1(unsigned long long res)
{
/* Build a rotate expression on a 40 bit argument. */
if ((x.b<<8) + (x.b>>32) != res)
abort ();
}
int main()
{
x.b = 0x0100000001;
test1(0x0000000101);
x.b = 0x0100000000;
test1(0x0000000001);
return 0;
}
--
rguenth at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
AssignedTo|unassigned at gcc dot gnu |rguenth at gcc dot gnu dot
|dot org |org
Status|NEW |ASSIGNED
Last reconfirmed|2007-06-08 10:28:26 |2008-01-25 13:23:02
date| |
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32244
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug middle-end/32244] bit-field: optimization BUG
2007-06-07 13:36 [Bug c/32244] New: bit-field: optimization BUG s__nakayama at infoseek dot jp
` (2 preceding siblings ...)
2008-01-25 14:21 ` rguenth at gcc dot gnu dot org
@ 2008-01-25 15:36 ` rguenth at gcc dot gnu dot org
2008-01-25 15:40 ` rguenth at gcc dot gnu dot org
2008-01-25 15:45 ` rguenth at gcc dot gnu dot org
5 siblings, 0 replies; 7+ messages in thread
From: rguenth at gcc dot gnu dot org @ 2008-01-25 15:36 UTC (permalink / raw)
To: gcc-bugs
------- Comment #4 from rguenth at gcc dot gnu dot org 2008-01-25 14:21 -------
I split off the rotate issues to PR34971.
--
rguenth at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
URL|http://gcc.gnu.org/ml/gcc- |
|patches/2008- |
|01/msg01224.html |
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32244
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug middle-end/32244] bit-field: optimization BUG
2007-06-07 13:36 [Bug c/32244] New: bit-field: optimization BUG s__nakayama at infoseek dot jp
` (3 preceding siblings ...)
2008-01-25 15:36 ` rguenth at gcc dot gnu dot org
@ 2008-01-25 15:40 ` rguenth at gcc dot gnu dot org
2008-01-25 15:45 ` rguenth at gcc dot gnu dot org
5 siblings, 0 replies; 7+ messages in thread
From: rguenth at gcc dot gnu dot org @ 2008-01-25 15:40 UTC (permalink / raw)
To: gcc-bugs
------- Comment #5 from rguenth at gcc dot gnu dot org 2008-01-25 15:33 -------
Subject: Bug 32244
Author: rguenth
Date: Fri Jan 25 15:33:09 2008
New Revision: 131828
URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=131828
Log:
2008-01-25 Richard Guenther <rguenther@suse.de>
PR middle-end/32244
* expr.c (expand_expr_real_1): Reduce result of LSHIFT_EXPR
to its bitfield precision if required.
* gcc.c-torture/execute/pr32244-1.c: New testcase.
Added:
trunk/gcc/testsuite/gcc.c-torture/execute/pr32244-1.c
Modified:
trunk/gcc/ChangeLog
trunk/gcc/expr.c
trunk/gcc/testsuite/ChangeLog
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32244
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug middle-end/32244] bit-field: optimization BUG
2007-06-07 13:36 [Bug c/32244] New: bit-field: optimization BUG s__nakayama at infoseek dot jp
` (4 preceding siblings ...)
2008-01-25 15:40 ` rguenth at gcc dot gnu dot org
@ 2008-01-25 15:45 ` rguenth at gcc dot gnu dot org
5 siblings, 0 replies; 7+ messages in thread
From: rguenth at gcc dot gnu dot org @ 2008-01-25 15:45 UTC (permalink / raw)
To: gcc-bugs
------- Comment #6 from rguenth at gcc dot gnu dot org 2008-01-25 15:37 -------
Fixed.
--
rguenth at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|ASSIGNED |RESOLVED
Known to work| |4.3.0
Resolution| |FIXED
Target Milestone|--- |4.3.0
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32244
^ permalink raw reply [flat|nested] 7+ messages in thread
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Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
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2007-06-07 13:36 [Bug c/32244] New: bit-field: optimization BUG s__nakayama at infoseek dot jp
2007-06-08 10:28 ` [Bug middle-end/32244] " rguenth at gcc dot gnu dot org
2007-12-11 13:55 ` rguenth at gcc dot gnu dot org
2008-01-25 14:21 ` rguenth at gcc dot gnu dot org
2008-01-25 15:36 ` rguenth at gcc dot gnu dot org
2008-01-25 15:40 ` rguenth at gcc dot gnu dot org
2008-01-25 15:45 ` rguenth at gcc dot gnu dot org
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