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* [Bug optimization/15061] New: c++ complex<double> arguments
@ 2004-04-22 4:41 jifl-bugzilla at jifvik dot org
2004-04-22 5:24 ` [Bug optimization/15061] " jifl-bugzilla at jifvik dot org
` (5 more replies)
0 siblings, 6 replies; 7+ messages in thread
From: jifl-bugzilla at jifvik dot org @ 2004-04-22 4:41 UTC (permalink / raw)
To: gcc-bugs
This is a bit of code compiled with g++ and using <complex> from libstdc++, but
the issue is an optimization one. Something Bad(tm) happens when complex
arguments are passed. The function prolog misuses the registers.
The small test case in question (which I'll attach separately) when compiled
with "arm-elf-g++ -O2" will produce the output:
Comparing (1,0) with (0,0)
(1,0) != (0,0)!
After a lot of playing I found it could also be reproduced with "arm-elf-g++ -O1
-fcse-skip-blocks":
Comparing (1,0) with (0,0)
(1,0) != (0,0)!
If compiled with "arm-elf-g++ -O2 -fno-cse-skip-blocks" however the problem does
not disappear, so I don't expect any issue with -fcse-skip-blocks itself, but it
just changes the optimizer state sufficiently. Curiously though, the output
isn't quite the same:
Comparing (1,0) with (1,0)
(1,0) != (0,0)!
Various other -fno-* options with -O2 can cause the problem to appear and
disappear as well, so beware of using a different gcc from 3.3.3 - just because
the problem doesn't appear per se doesn't mean it has been fixed!
I tried a native linux gcc 3.3.3 on the test case and it works which may well
mean it's arm specific.
Looking at the generated assembler (in the -O1 -fcse-skip-blocks example) I
thought at first glance there was a problem in main:
adr r2, .L20
ldmia r2, {r2-r3}
adr r4, .L20+8
ldmia r4, {r4-r5}
where .L20 is:
.L20:
.word 1072693248
.word 0
.word 0
.word 0
However the -O1 code which appears to run correctly also has .L20 defined like
that. If compiled with -O0 something it indeed has the equivalent of the first
two words of .L20 being used to load both z1 and z2 which is more what I'd
expect. So maybe there are in fact two problems here? One where .L20 is defined
as above, and another being a code generation issue.
NB I haven't been able to play with 3.4 due to problems with it on my target.
Let me know if you want more info.
--
Summary: c++ complex<double> arguments
Product: gcc
Version: 3.3.3
Status: UNCONFIRMED
Severity: normal
Priority: P2
Component: optimization
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: jifl-bugzilla at jifvik dot org
CC: gcc-bugs at gcc dot gnu dot org
GCC build triplet: i686-pc-linux-gnulibc2
GCC host triplet: i686-pc-linux-gnulibc2
GCC target triplet: arm-elf
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15061
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug optimization/15061] c++ complex<double> arguments
2004-04-22 4:41 [Bug optimization/15061] New: c++ complex<double> arguments jifl-bugzilla at jifvik dot org
@ 2004-04-22 5:24 ` jifl-bugzilla at jifvik dot org
2004-04-22 5:25 ` pinskia at gcc dot gnu dot org
` (4 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: jifl-bugzilla at jifvik dot org @ 2004-04-22 5:24 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From jifl-bugzilla at jifvik dot org 2004-04-22 04:31 -------
Created an attachment (id=6135)
--> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=6135&action=view)
Test case showing failure
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15061
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug optimization/15061] c++ complex<double> arguments
2004-04-22 4:41 [Bug optimization/15061] New: c++ complex<double> arguments jifl-bugzilla at jifvik dot org
2004-04-22 5:24 ` [Bug optimization/15061] " jifl-bugzilla at jifvik dot org
@ 2004-04-22 5:25 ` pinskia at gcc dot gnu dot org
2004-04-22 5:38 ` jifl-bugzilla at jifvik dot org
` (3 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2004-04-22 5:25 UTC (permalink / raw)
To: gcc-bugs
--
What |Removed |Added
----------------------------------------------------------------------------
Keywords| |wrong-code
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15061
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug optimization/15061] c++ complex<double> arguments
2004-04-22 4:41 [Bug optimization/15061] New: c++ complex<double> arguments jifl-bugzilla at jifvik dot org
2004-04-22 5:24 ` [Bug optimization/15061] " jifl-bugzilla at jifvik dot org
2004-04-22 5:25 ` pinskia at gcc dot gnu dot org
@ 2004-04-22 5:38 ` jifl-bugzilla at jifvik dot org
2004-05-26 20:12 ` [Bug target/15061] " pinskia at gcc dot gnu dot org
` (2 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: jifl-bugzilla at jifvik dot org @ 2004-04-22 5:38 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From jifl-bugzilla at jifvik dot org 2004-04-22 04:41 -------
Actually forget what I said about .L20 etc. I've just realised that the
assembler generated there is okay... it just slipped my mind that the complex
will be 4 words long, two for each double.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15061
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug target/15061] c++ complex<double> arguments
2004-04-22 4:41 [Bug optimization/15061] New: c++ complex<double> arguments jifl-bugzilla at jifvik dot org
` (2 preceding siblings ...)
2004-04-22 5:38 ` jifl-bugzilla at jifvik dot org
@ 2004-05-26 20:12 ` pinskia at gcc dot gnu dot org
2004-10-07 9:24 ` giovannibajo at libero dot it
2004-12-12 14:45 ` [Bug target/15061] [arm] " lerdsuwa at gcc dot gnu dot org
5 siblings, 0 replies; 7+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2004-05-26 20:12 UTC (permalink / raw)
To: gcc-bugs
--
What |Removed |Added
----------------------------------------------------------------------------
Component|rtl-optimization |target
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15061
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug target/15061] c++ complex<double> arguments
2004-04-22 4:41 [Bug optimization/15061] New: c++ complex<double> arguments jifl-bugzilla at jifvik dot org
` (3 preceding siblings ...)
2004-05-26 20:12 ` [Bug target/15061] " pinskia at gcc dot gnu dot org
@ 2004-10-07 9:24 ` giovannibajo at libero dot it
2004-12-12 14:45 ` [Bug target/15061] [arm] " lerdsuwa at gcc dot gnu dot org
5 siblings, 0 replies; 7+ messages in thread
From: giovannibajo at libero dot it @ 2004-10-07 9:24 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From giovannibajo at libero dot it 2004-10-07 09:24 -------
Richard, Paul, this is an ARM problem. Would you please give a look?
--
What |Removed |Added
----------------------------------------------------------------------------
CC| |rearnsha at gcc dot gnu dot
| |org, pbrook at gcc dot gnu
| |dot org
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15061
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug target/15061] [arm] c++ complex<double> arguments
2004-04-22 4:41 [Bug optimization/15061] New: c++ complex<double> arguments jifl-bugzilla at jifvik dot org
` (4 preceding siblings ...)
2004-10-07 9:24 ` giovannibajo at libero dot it
@ 2004-12-12 14:45 ` lerdsuwa at gcc dot gnu dot org
5 siblings, 0 replies; 7+ messages in thread
From: lerdsuwa at gcc dot gnu dot org @ 2004-12-12 14:45 UTC (permalink / raw)
To: gcc-bugs
--
What |Removed |Added
----------------------------------------------------------------------------
Summary|c++ complex<double> |[arm] c++ complex<double>
|arguments |arguments
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15061
^ permalink raw reply [flat|nested] 7+ messages in thread
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2004-04-22 4:41 [Bug optimization/15061] New: c++ complex<double> arguments jifl-bugzilla at jifvik dot org
2004-04-22 5:24 ` [Bug optimization/15061] " jifl-bugzilla at jifvik dot org
2004-04-22 5:25 ` pinskia at gcc dot gnu dot org
2004-04-22 5:38 ` jifl-bugzilla at jifvik dot org
2004-05-26 20:12 ` [Bug target/15061] " pinskia at gcc dot gnu dot org
2004-10-07 9:24 ` giovannibajo at libero dot it
2004-12-12 14:45 ` [Bug target/15061] [arm] " lerdsuwa at gcc dot gnu dot org
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