* [Bug tree-optimization/54634] [4.8 Regression] miscompilation with -O3 -ftree-loop-distribution
2012-09-20 8:55 [Bug tree-optimization/54634] New: [4.8 Regression] miscompilation with -O3 -ftree-loop-distribution Joost.VandeVondele at mat dot ethz.ch
@ 2012-09-20 8:58 ` jakub at gcc dot gnu.org
2012-09-20 10:17 ` Joost.VandeVondele at mat dot ethz.ch
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From: jakub at gcc dot gnu.org @ 2012-09-20 8:58 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54634
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |jakub at gcc dot gnu.org
--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> 2012-09-20 08:58:02 UTC ---
Retry with PR54629 fix?
^ permalink raw reply [flat|nested] 9+ messages in thread* [Bug tree-optimization/54634] [4.8 Regression] miscompilation with -O3 -ftree-loop-distribution
2012-09-20 8:55 [Bug tree-optimization/54634] New: [4.8 Regression] miscompilation with -O3 -ftree-loop-distribution Joost.VandeVondele at mat dot ethz.ch
2012-09-20 8:58 ` [Bug tree-optimization/54634] " jakub at gcc dot gnu.org
@ 2012-09-20 10:17 ` Joost.VandeVondele at mat dot ethz.ch
2012-09-20 11:30 ` rguenth at gcc dot gnu.org
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From: Joost.VandeVondele at mat dot ethz.ch @ 2012-09-20 10:17 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54634
--- Comment #2 from Joost VandeVondele <Joost.VandeVondele at mat dot ethz.ch> 2012-09-20 10:15:57 UTC ---
(In reply to comment #1)
> Retry with PR54629 fix?
after applying the patch mentioned above, the testcase still fails. The failure
is also older than the commit mentioned in PR54629
^ permalink raw reply [flat|nested] 9+ messages in thread* [Bug tree-optimization/54634] [4.8 Regression] miscompilation with -O3 -ftree-loop-distribution
2012-09-20 8:55 [Bug tree-optimization/54634] New: [4.8 Regression] miscompilation with -O3 -ftree-loop-distribution Joost.VandeVondele at mat dot ethz.ch
2012-09-20 8:58 ` [Bug tree-optimization/54634] " jakub at gcc dot gnu.org
2012-09-20 10:17 ` Joost.VandeVondele at mat dot ethz.ch
@ 2012-09-20 11:30 ` rguenth at gcc dot gnu.org
2012-09-20 12:27 ` rguenth at gcc dot gnu.org
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From: rguenth at gcc dot gnu.org @ 2012-09-20 11:30 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54634
Richard Guenther <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Keywords| |wrong-code
Status|UNCONFIRMED |ASSIGNED
Last reconfirmed| |2012-09-20
AssignedTo|unassigned at gcc dot |rguenth at gcc dot gnu.org
|gnu.org |
Target Milestone|--- |4.8.0
Ever Confirmed|0 |1
--- Comment #3 from Richard Guenther <rguenth at gcc dot gnu.org> 2012-09-20 11:29:51 UTC ---
Mine.
^ permalink raw reply [flat|nested] 9+ messages in thread* [Bug tree-optimization/54634] [4.8 Regression] miscompilation with -O3 -ftree-loop-distribution
2012-09-20 8:55 [Bug tree-optimization/54634] New: [4.8 Regression] miscompilation with -O3 -ftree-loop-distribution Joost.VandeVondele at mat dot ethz.ch
` (2 preceding siblings ...)
2012-09-20 11:30 ` rguenth at gcc dot gnu.org
@ 2012-09-20 12:27 ` rguenth at gcc dot gnu.org
2012-09-20 13:07 ` Joost.VandeVondele at mat dot ethz.ch
` (3 subsequent siblings)
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From: rguenth at gcc dot gnu.org @ 2012-09-20 12:27 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54634
--- Comment #4 from Richard Guenther <rguenth at gcc dot gnu.org> 2012-09-20 12:26:53 UTC ---
We split
<bb 89>:
# s2_207 = PHI <0.0(88), s2_524(91)>
# prephitmp_1456 = PHI <0(88), k.76_530(91)>
_496 = prephitmp_1456 * -2;
_1535 = lx_355 + _496;
D.3330 = _1535;
_1533 = binomial (&j, &k);
_517 = binomial (&ma, &D.3330);
_518 = _1533 * _517;
_520 = _518 * 0.0;
s2_524 = _520 + s2_207;
D.3330 ={v} {CLOBBER};
k.76_530 = prephitmp_1456 + 1;
k = k.76_530;
if (j.72_383 == prephitmp_1456)
goto <bb 90>;
else
goto <bb 91>;
into bogus pieces:
<bb 204>:
# prephitmp_1664 = PHI <k.76_1674(205), 0(88)>
_1665 = prephitmp_1664 * -2;
_1666 = lx_355 + _1665;
D.3330 = _1666;
D.3330 ={v} {CLOBBER};
k.76_1674 = prephitmp_1664 + 1;
if (j.72_383 == prephitmp_1664)
goto <bb 206>;
else
goto <bb 205>;
split for the store D.3330 (huh, well ...), but somehow lost the
binomial call here.
<bb 207>:
# prephitmp_1678 = PHI <k.76_1688(208), 0(206)>
k.76_1688 = prephitmp_1678 + 1;
k = k.76_1688;
if (j.72_383 == prephitmp_1678)
goto <bb 209>;
else
goto <bb 208>;
well ... likewise.
<bb 89>:
# s2_207 = PHI <0.0(209), s2_524(91)>
# prephitmp_1456 = PHI <0(209), k.76_530(91)>
_1533 = binomial (&j, &k);
_517 = binomial (&ma, &D.3330);
_518 = _1533 * _517;
_520 = _518 * 0.0;
s2_524 = _520 + s2_207;
k.76_530 = prephitmp_1456 + 1;
if (j.72_383 == prephitmp_1456)
goto <bb 90>;
else
goto <bb 91>;
finally all the calls. Investigating some more.
Ah, binomial () is pure. The RDG is bogus, it does not consider
calls that merely read unknown memory. That is because
get_references_in_stmt handles calls by returning true/false only ...
in this case it doesn't add any data references.
So it's a very old problem that bites us now.
*sigh*
^ permalink raw reply [flat|nested] 9+ messages in thread* [Bug tree-optimization/54634] [4.8 Regression] miscompilation with -O3 -ftree-loop-distribution
2012-09-20 8:55 [Bug tree-optimization/54634] New: [4.8 Regression] miscompilation with -O3 -ftree-loop-distribution Joost.VandeVondele at mat dot ethz.ch
` (3 preceding siblings ...)
2012-09-20 12:27 ` rguenth at gcc dot gnu.org
@ 2012-09-20 13:07 ` Joost.VandeVondele at mat dot ethz.ch
2012-09-20 13:44 ` rguenther at suse dot de
` (2 subsequent siblings)
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From: Joost.VandeVondele at mat dot ethz.ch @ 2012-09-20 13:07 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54634
--- Comment #5 from Joost VandeVondele <Joost.VandeVondele at mat dot ethz.ch> 2012-09-20 13:06:50 UTC ---
(In reply to comment #4)
> Ah, binomial () is pure.
In this case, it was presumably triggered by Tobias' changes for PR54389.
binomial() has not been declared pure in the source, but most likely correctly
declared 'implicitly pure' but the Fortran frontend.
^ permalink raw reply [flat|nested] 9+ messages in thread* [Bug tree-optimization/54634] [4.8 Regression] miscompilation with -O3 -ftree-loop-distribution
2012-09-20 8:55 [Bug tree-optimization/54634] New: [4.8 Regression] miscompilation with -O3 -ftree-loop-distribution Joost.VandeVondele at mat dot ethz.ch
` (4 preceding siblings ...)
2012-09-20 13:07 ` Joost.VandeVondele at mat dot ethz.ch
@ 2012-09-20 13:44 ` rguenther at suse dot de
2012-09-20 14:47 ` rguenth at gcc dot gnu.org
2012-09-20 14:49 ` rguenth at gcc dot gnu.org
7 siblings, 0 replies; 9+ messages in thread
From: rguenther at suse dot de @ 2012-09-20 13:44 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54634
--- Comment #6 from rguenther at suse dot de <rguenther at suse dot de> 2012-09-20 13:43:33 UTC ---
On Thu, 20 Sep 2012, Joost.VandeVondele at mat dot ethz.ch wrote:
>
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54634
>
> --- Comment #5 from Joost VandeVondele <Joost.VandeVondele at mat dot ethz.ch> 2012-09-20 13:06:50 UTC ---
> (In reply to comment #4)
> > Ah, binomial () is pure.
>
> In this case, it was presumably triggered by Tobias' changes for PR54389.
> binomial() has not been declared pure in the source, but most likely correctly
> declared 'implicitly pure' but the Fortran frontend.
Btw, it's just what triggers the latent bug in data dependence analysis.
I am testing
Index: gcc/tree-data-ref.c
===================================================================
--- gcc/tree-data-ref.c (revision 191561)
+++ gcc/tree-data-ref.c (working copy)
@@ -4307,10 +4307,10 @@ get_references_in_stmt (gimple stmt, VEC
*references = NULL;
/* ASM_EXPR and CALL_EXPR may embed arbitrary side effects.
- Calls have side-effects, except those to const or pure
- functions. */
+ As we cannot model data-references to not spelled out
+ accesses give up if they may occur. */
if ((stmt_code == GIMPLE_CALL
- && !(gimple_call_flags (stmt) & (ECF_CONST | ECF_PURE)))
+ && !(gimple_call_flags (stmt) & ECF_CONST))
|| (stmt_code == GIMPLE_ASM
&& (gimple_asm_volatile_p (stmt) || gimple_vuse (stmt))))
clobbers_memory = true;
currently.
^ permalink raw reply [flat|nested] 9+ messages in thread* [Bug tree-optimization/54634] [4.8 Regression] miscompilation with -O3 -ftree-loop-distribution
2012-09-20 8:55 [Bug tree-optimization/54634] New: [4.8 Regression] miscompilation with -O3 -ftree-loop-distribution Joost.VandeVondele at mat dot ethz.ch
` (5 preceding siblings ...)
2012-09-20 13:44 ` rguenther at suse dot de
@ 2012-09-20 14:47 ` rguenth at gcc dot gnu.org
2012-09-20 14:49 ` rguenth at gcc dot gnu.org
7 siblings, 0 replies; 9+ messages in thread
From: rguenth at gcc dot gnu.org @ 2012-09-20 14:47 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54634
--- Comment #7 from Richard Guenther <rguenth at gcc dot gnu.org> 2012-09-20 14:46:41 UTC ---
Author: rguenth
Date: Thu Sep 20 14:46:32 2012
New Revision: 191567
URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=191567
Log:
2012-09-20 Richard Guenther <rguenther@suse.de>
PR tree-optimization/54634
* tree-data-ref.c (get_references_in_stmt): For now give
up for pure functions.
Modified:
trunk/gcc/ChangeLog
trunk/gcc/tree-data-ref.c
^ permalink raw reply [flat|nested] 9+ messages in thread* [Bug tree-optimization/54634] [4.8 Regression] miscompilation with -O3 -ftree-loop-distribution
2012-09-20 8:55 [Bug tree-optimization/54634] New: [4.8 Regression] miscompilation with -O3 -ftree-loop-distribution Joost.VandeVondele at mat dot ethz.ch
` (6 preceding siblings ...)
2012-09-20 14:47 ` rguenth at gcc dot gnu.org
@ 2012-09-20 14:49 ` rguenth at gcc dot gnu.org
7 siblings, 0 replies; 9+ messages in thread
From: rguenth at gcc dot gnu.org @ 2012-09-20 14:49 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54634
Richard Guenther <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|ASSIGNED |RESOLVED
Resolution| |FIXED
--- Comment #8 from Richard Guenther <rguenth at gcc dot gnu.org> 2012-09-20 14:48:57 UTC ---
Fixed.
^ permalink raw reply [flat|nested] 9+ messages in thread