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* [Bug tree-optimization/47239] New: (int)&func & 3 is always optimized to 0 on some targets
@ 2011-01-10 0:01 kkojima at gcc dot gnu.org
2011-01-11 13:03 ` [Bug tree-optimization/47239] [4.6 Regression] " rguenth at gcc dot gnu.org
` (3 more replies)
0 siblings, 4 replies; 5+ messages in thread
From: kkojima at gcc dot gnu.org @ 2011-01-10 0:01 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47239
Summary: (int)&func & 3 is always optimized to 0 on some
targets
Product: gcc
Version: 4.6.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
AssignedTo: unassigned@gcc.gnu.org
ReportedBy: kkojima@gcc.gnu.org
Targets like arm, hppa and sh64 use the lower bits of the address
of functions for special purposes. Even on those targets,
----
extern void plabel32_function (void);
int
is_plabel32 (void)
{
return ((unsigned long) &plabel32_function & 3);
}
----
which was the test case of PR 35705, is wrongly compiled with -O2.
It seems that tree-bit-ccp optimization evaluates the expression
((unsigned long) &plabel32_function & 3) to zero always.
With -fno-tree-bit-ccp, the result looks OK. For example, arm-eabi
compiler outputs
mov r0, #0
bx lr
with -O2 and
ldr r0, .L2
and r0, r0, #3
bx lr
.L3:
.align 2
.L2:
.word plabel32_function
with -O2 -fno-tree-bit-ccp. I've got similar results for hppa and sh64
compilers.
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug tree-optimization/47239] [4.6 Regression] (int)&func & 3 is always optimized to 0 on some targets
2011-01-10 0:01 [Bug tree-optimization/47239] New: (int)&func & 3 is always optimized to 0 on some targets kkojima at gcc dot gnu.org
@ 2011-01-11 13:03 ` rguenth at gcc dot gnu.org
2011-01-11 14:33 ` rguenth at gcc dot gnu.org
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: rguenth at gcc dot gnu.org @ 2011-01-11 13:03 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47239
Richard Guenther <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |ASSIGNED
Last reconfirmed| |2011.01.11 12:53:34
AssignedTo|unassigned at gcc dot |rguenth at gcc dot gnu.org
|gnu.org |
Target Milestone|--- |4.6.0
Summary|(int)&func & 3 is always |[4.6 Regression] (int)&func
|optimized to 0 on some |& 3 is always optimized to
|targets |0 on some targets
Ever Confirmed|0 |1
--- Comment #1 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-01-11 12:53:34 UTC ---
Confirmed, mine. The fix for PR35705 only extracts alignment information
from function decls for the single case &fn & 1. That's odd. I'm going
to simply punt for function-decls for now.
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug tree-optimization/47239] [4.6 Regression] (int)&func & 3 is always optimized to 0 on some targets
2011-01-10 0:01 [Bug tree-optimization/47239] New: (int)&func & 3 is always optimized to 0 on some targets kkojima at gcc dot gnu.org
2011-01-11 13:03 ` [Bug tree-optimization/47239] [4.6 Regression] " rguenth at gcc dot gnu.org
@ 2011-01-11 14:33 ` rguenth at gcc dot gnu.org
2011-01-11 23:17 ` kkojima at gcc dot gnu.org
2011-01-12 13:10 ` rguenth at gcc dot gnu.org
3 siblings, 0 replies; 5+ messages in thread
From: rguenth at gcc dot gnu.org @ 2011-01-11 14:33 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47239
--- Comment #2 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-01-11 14:23:23 UTC ---
Author: rguenth
Date: Tue Jan 11 14:23:20 2011
New Revision: 168661
URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=168661
Log:
2011-01-11 Richard Guenther <rguenther@suse.de>
PR tree-optimization/47239
* tree-ssa-ccp.c (get_value_from_alignment): Punt for FUNCTION_DECLs.
Modified:
trunk/gcc/ChangeLog
trunk/gcc/tree-ssa-ccp.c
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug tree-optimization/47239] [4.6 Regression] (int)&func & 3 is always optimized to 0 on some targets
2011-01-10 0:01 [Bug tree-optimization/47239] New: (int)&func & 3 is always optimized to 0 on some targets kkojima at gcc dot gnu.org
2011-01-11 13:03 ` [Bug tree-optimization/47239] [4.6 Regression] " rguenth at gcc dot gnu.org
2011-01-11 14:33 ` rguenth at gcc dot gnu.org
@ 2011-01-11 23:17 ` kkojima at gcc dot gnu.org
2011-01-12 13:10 ` rguenth at gcc dot gnu.org
3 siblings, 0 replies; 5+ messages in thread
From: kkojima at gcc dot gnu.org @ 2011-01-11 23:17 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47239
--- Comment #3 from Kazumoto Kojima <kkojima at gcc dot gnu.org> 2011-01-11 23:14:45 UTC ---
I've tried 168661 with arm, hppa and sh64 cc1's. The problem
has gone away on all these 3 targets. Thanks!
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug tree-optimization/47239] [4.6 Regression] (int)&func & 3 is always optimized to 0 on some targets
2011-01-10 0:01 [Bug tree-optimization/47239] New: (int)&func & 3 is always optimized to 0 on some targets kkojima at gcc dot gnu.org
` (2 preceding siblings ...)
2011-01-11 23:17 ` kkojima at gcc dot gnu.org
@ 2011-01-12 13:10 ` rguenth at gcc dot gnu.org
3 siblings, 0 replies; 5+ messages in thread
From: rguenth at gcc dot gnu.org @ 2011-01-12 13:10 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47239
Richard Guenther <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|ASSIGNED |RESOLVED
Resolution| |FIXED
--- Comment #4 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-01-12 12:10:05 UTC ---
Fixed.
^ permalink raw reply [flat|nested] 5+ messages in thread
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2011-01-10 0:01 [Bug tree-optimization/47239] New: (int)&func & 3 is always optimized to 0 on some targets kkojima at gcc dot gnu.org
2011-01-11 13:03 ` [Bug tree-optimization/47239] [4.6 Regression] " rguenth at gcc dot gnu.org
2011-01-11 14:33 ` rguenth at gcc dot gnu.org
2011-01-11 23:17 ` kkojima at gcc dot gnu.org
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