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* [Bug target/44073] New: x86 constants could be unduplicated
@ 2010-05-11 8:14 astrange at ithinksw dot com
2010-05-11 8:43 ` [Bug target/44073] " rguenth at gcc dot gnu dot org
` (4 more replies)
0 siblings, 5 replies; 6+ messages in thread
From: astrange at ithinksw dot com @ 2010-05-11 8:14 UTC (permalink / raw)
To: gcc-bugs
void f1(int *a, int *b, int *c)
{
int d = 0xE0E0E0E0;
*a = *b = *c = d;
}
produces
_f1:
LFB0:
movl $-522133280, (%rdx)
movl $-522133280, (%rsi)
movl $-522133280, (%rdi)
ret
on x86-64 at -Os. It would save instruction space and probably not be any
slower to actually assign d to a register, but this is only done for 64-bit
constants.
--
Summary: x86 constants could be unduplicated
Product: gcc
Version: 4.6.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: astrange at ithinksw dot com
GCC host triplet: x86_64-*-*
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44073
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug target/44073] x86 constants could be unduplicated
2010-05-11 8:14 [Bug target/44073] New: x86 constants could be unduplicated astrange at ithinksw dot com
@ 2010-05-11 8:43 ` rguenth at gcc dot gnu dot org
2010-05-11 10:24 ` steven at gcc dot gnu dot org
` (3 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: rguenth at gcc dot gnu dot org @ 2010-05-11 8:43 UTC (permalink / raw)
To: gcc-bugs
------- Comment #1 from rguenth at gcc dot gnu dot org 2010-05-11 08:42 -------
Confirmed.
--
rguenth at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Ever Confirmed|0 |1
Last reconfirmed|0000-00-00 00:00:00 |2010-05-11 08:42:34
date| |
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44073
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug target/44073] x86 constants could be unduplicated
2010-05-11 8:14 [Bug target/44073] New: x86 constants could be unduplicated astrange at ithinksw dot com
2010-05-11 8:43 ` [Bug target/44073] " rguenth at gcc dot gnu dot org
@ 2010-05-11 10:24 ` steven at gcc dot gnu dot org
2010-05-11 10:36 ` astrange at ithinksw dot com
` (2 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: steven at gcc dot gnu dot org @ 2010-05-11 10:24 UTC (permalink / raw)
To: gcc-bugs
------- Comment #2 from steven at gcc dot gnu dot org 2010-05-11 10:24 -------
There is a GIMPLE uncprop pass for this. Could you verify that after this pass
there is just one assignment of the constant to an SSA_NAME? If so, the problem
is in the RTL CPROP pass, otherwise we have to look at the GIMPLE pass first.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44073
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug target/44073] x86 constants could be unduplicated
2010-05-11 8:14 [Bug target/44073] New: x86 constants could be unduplicated astrange at ithinksw dot com
2010-05-11 8:43 ` [Bug target/44073] " rguenth at gcc dot gnu dot org
2010-05-11 10:24 ` steven at gcc dot gnu dot org
@ 2010-05-11 10:36 ` astrange at ithinksw dot com
2010-07-24 21:37 ` pinskia at gcc dot gnu dot org
2010-08-08 6:39 ` astrange at ithinksw dot com
4 siblings, 0 replies; 6+ messages in thread
From: astrange at ithinksw dot com @ 2010-05-11 10:36 UTC (permalink / raw)
To: gcc-bugs
------- Comment #3 from astrange at ithinksw dot com 2010-05-11 10:36 -------
It's propagated by vrp1, and then nothing removes it again. tree-uncprop
doesn't change it - it looks like it doesn't have anything to handle this,
actually.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44073
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug target/44073] x86 constants could be unduplicated
2010-05-11 8:14 [Bug target/44073] New: x86 constants could be unduplicated astrange at ithinksw dot com
` (2 preceding siblings ...)
2010-05-11 10:36 ` astrange at ithinksw dot com
@ 2010-07-24 21:37 ` pinskia at gcc dot gnu dot org
2010-08-08 6:39 ` astrange at ithinksw dot com
4 siblings, 0 replies; 6+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2010-07-24 21:37 UTC (permalink / raw)
To: gcc-bugs
------- Comment #4 from pinskia at gcc dot gnu dot org 2010-07-24 21:37 -------
CSE/GCSE should be doing it. Oh but CSE does not handle RTL like:
(insn 8 5 9 2 t.c:5 (set (mem:SI (reg/v/f:DI 60 [ c ]) [2 *c_2(D)+0 S4 A32])
(const_int -522133280 [0xffffffffe0e0e0e0])) 63 {*movsi_internal}
(nil))
Related to PR 23488.
What happens if you revert:
2005-07-30 Jan Hubicka <jh@suse.cz>
* expr.c (expand_expr_real_1): Do not load mem targets into register.
* i386.c (ix86_fixup_binary_operands): Likewise.
(ix86_expand_unary_operator): Likewise.
(ix86_expand_fp_absneg_operator): Likewise.
* optabs.c (expand_vec_cond_expr): Validate dest.
--
pinskia at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
GCC host triplet|x86_64-*-* |
GCC target triplet| |x86_64-*-*
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44073
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug target/44073] x86 constants could be unduplicated
2010-05-11 8:14 [Bug target/44073] New: x86 constants could be unduplicated astrange at ithinksw dot com
` (3 preceding siblings ...)
2010-07-24 21:37 ` pinskia at gcc dot gnu dot org
@ 2010-08-08 6:39 ` astrange at ithinksw dot com
4 siblings, 0 replies; 6+ messages in thread
From: astrange at ithinksw dot com @ 2010-08-08 6:39 UTC (permalink / raw)
To: gcc-bugs
------- Comment #5 from astrange at ithinksw dot com 2010-08-08 06:39 -------
That commit doesn't reverse cleanly anymore, and I'm not sure how to update it.
I don't have any pre-2005 gccs at the moment to test with.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44073
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2010-08-08 6:39 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
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2010-05-11 8:14 [Bug target/44073] New: x86 constants could be unduplicated astrange at ithinksw dot com
2010-05-11 8:43 ` [Bug target/44073] " rguenth at gcc dot gnu dot org
2010-05-11 10:24 ` steven at gcc dot gnu dot org
2010-05-11 10:36 ` astrange at ithinksw dot com
2010-07-24 21:37 ` pinskia at gcc dot gnu dot org
2010-08-08 6:39 ` astrange at ithinksw dot com
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