* [Bug c/30936] const attribute in nanf prototype causes gcc not producing correct code.
2007-02-23 15:39 [Bug c/30936] New: const attribute in nanf prototype causes gcc not producing correct code filippo dot arcidiacono at gmail dot com
@ 2007-02-23 15:43 ` filippo dot arcidiacono at gmail dot com
2007-02-23 17:39 ` pinskia at gcc dot gnu dot org
` (6 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: filippo dot arcidiacono at gmail dot com @ 2007-02-23 15:43 UTC (permalink / raw)
To: gcc-bugs
------- Comment #1 from filippo dot arcidiacono at gmail dot com 2007-02-23 15:43 -------
Created an attachment (id=13100)
--> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=13100&action=view)
simple test case exploiting gcc bug
compiled with the following command:
> sh4-linux-gcc nanf-test.c -D_GNU_SOURCE -o nanf-test -lm
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30936
^ permalink raw reply [flat|nested] 9+ messages in thread* [Bug c/30936] const attribute in nanf prototype causes gcc not producing correct code.
2007-02-23 15:39 [Bug c/30936] New: const attribute in nanf prototype causes gcc not producing correct code filippo dot arcidiacono at gmail dot com
2007-02-23 15:43 ` [Bug c/30936] " filippo dot arcidiacono at gmail dot com
@ 2007-02-23 17:39 ` pinskia at gcc dot gnu dot org
2007-02-26 8:08 ` filippo dot arcidiacono at gmail dot com
` (5 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2007-02-23 17:39 UTC (permalink / raw)
To: gcc-bugs
------- Comment #2 from pinskia at gcc dot gnu dot org 2007-02-23 17:39 -------
> Being nanf declared using const attribute
Can you attach the preprocessed source which you can get by adding -save-temps
to the command line? The file will be called something.i.
Also can you compile with -W -Wall as I think really nanf is not being
prototyped which means this is not a GCC issue.
--
pinskia at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |WAITING
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30936
^ permalink raw reply [flat|nested] 9+ messages in thread* [Bug c/30936] const attribute in nanf prototype causes gcc not producing correct code.
2007-02-23 15:39 [Bug c/30936] New: const attribute in nanf prototype causes gcc not producing correct code filippo dot arcidiacono at gmail dot com
2007-02-23 15:43 ` [Bug c/30936] " filippo dot arcidiacono at gmail dot com
2007-02-23 17:39 ` pinskia at gcc dot gnu dot org
@ 2007-02-26 8:08 ` filippo dot arcidiacono at gmail dot com
2007-02-26 8:21 ` [Bug target/30936] " pinskia at gcc dot gnu dot org
` (4 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: filippo dot arcidiacono at gmail dot com @ 2007-02-26 8:08 UTC (permalink / raw)
To: gcc-bugs
------- Comment #3 from filippo dot arcidiacono at gmail dot com 2007-02-26 08:08 -------
Created an attachment (id=13111)
--> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=13111&action=view)
prerprocessed file of nanf-test.c
In attach you can find the preprocessed file nanf-test.i of nanf-test.c.
It contains the nanf prototype, declared by bits/mathcalls.h included by math.h
header file.
Using -Wall option I doesn't obtain any warning.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30936
^ permalink raw reply [flat|nested] 9+ messages in thread* [Bug target/30936] const attribute in nanf prototype causes gcc not producing correct code.
2007-02-23 15:39 [Bug c/30936] New: const attribute in nanf prototype causes gcc not producing correct code filippo dot arcidiacono at gmail dot com
` (2 preceding siblings ...)
2007-02-26 8:08 ` filippo dot arcidiacono at gmail dot com
@ 2007-02-26 8:21 ` pinskia at gcc dot gnu dot org
2007-02-26 9:29 ` filippo dot arcidiacono at gmail dot com
` (3 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2007-02-26 8:21 UTC (permalink / raw)
To: gcc-bugs
------- Comment #4 from pinskia at gcc dot gnu dot org 2007-02-26 08:21 -------
No, the const attribute does not cause to produce wrong code.
On powerpc-darwin with your testcase, I get:
mflr r0
lis r3,ha16(LC0)
la r3,lo16(LC0)(r3)
stw r0,8(r1)
stwu r1,-64(r1)
bl _nanf
li r3,0
fcmpu cr7,f1,f1
bne- cr7,L5
You can see the floating point compare happens but only one call to nanf.
--
pinskia at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Component|c |target
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30936
^ permalink raw reply [flat|nested] 9+ messages in thread* [Bug target/30936] const attribute in nanf prototype causes gcc not producing correct code.
2007-02-23 15:39 [Bug c/30936] New: const attribute in nanf prototype causes gcc not producing correct code filippo dot arcidiacono at gmail dot com
` (3 preceding siblings ...)
2007-02-26 8:21 ` [Bug target/30936] " pinskia at gcc dot gnu dot org
@ 2007-02-26 9:29 ` filippo dot arcidiacono at gmail dot com
2007-02-26 9:52 ` [Bug target/30936] __builtin_nanf("") != __builtin_nanf("") is false for sh4-linux-gnu pinskia at gcc dot gnu dot org
` (2 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: filippo dot arcidiacono at gmail dot com @ 2007-02-26 9:29 UTC (permalink / raw)
To: gcc-bugs
------- Comment #5 from filippo dot arcidiacono at gmail dot com 2007-02-26 09:29 -------
Created an attachment (id=13112)
--> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=13112&action=view)
assembler code of nanf-test.c
Following a piece of the objdump of the nanf-test:
:
:
int
main (void)
{
0: e6 2f mov.l r14,@-r15
2: 22 4f sts.l pr,@-r15
4: f8 7f add #-8,r15
6: f3 6e mov r15,r14
int op;
op = (nanf ("") != nanf ("") );
8: e3 62 mov r14,r2
a: c8 72 add #-56,r2
c: 00 e1 mov #0,r1
e: 1f 12 mov.l r1,@(60,r2)
if (!op) {
10: e3 61 mov r14,r1
12: c8 71 add #-56,r1
14: 1f 51 mov.l @(60,r1),r1
16: 18 21 tst r1,r1
18: 08 8b bf 2c <main+0x2c>
printf ("Test NAN Failed!\n");
1a: 09 d1 mov.l 40 <main+0x40>,r1 ! 0x0 <main>
1c: 13 64 mov r1,r4
1e: 09 d1 mov.l 44 <main+0x44>,r1 ! 0x0 <main>
20: 0b 41 jsr @r1
22: 09 00 nop
return (1);
24: 01 e1 mov #1,r1
26: 12 2e mov.l r1,@r14
28: 02 a0 bra 30 <main+0x30>
2a: 09 00 nop
}
:
:
Note that I using sh4 architecture.
In attach you can find the nanf-test.s that doesn't contains any reference
to nanf symbol.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30936
^ permalink raw reply [flat|nested] 9+ messages in thread* [Bug target/30936] __builtin_nanf("") != __builtin_nanf("") is false for sh4-linux-gnu
2007-02-23 15:39 [Bug c/30936] New: const attribute in nanf prototype causes gcc not producing correct code filippo dot arcidiacono at gmail dot com
` (4 preceding siblings ...)
2007-02-26 9:29 ` filippo dot arcidiacono at gmail dot com
@ 2007-02-26 9:52 ` pinskia at gcc dot gnu dot org
2007-02-26 13:01 ` filippo dot arcidiacono at gmail dot com
2007-02-26 18:02 ` pinskia at gcc dot gnu dot org
7 siblings, 0 replies; 9+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2007-02-26 9:52 UTC (permalink / raw)
To: gcc-bugs
------- Comment #6 from pinskia at gcc dot gnu dot org 2007-02-26 09:52 -------
>In attach you can find the nanf-test.s that doesn't contains any reference
> to nanf symbol.
That is ok, because nanf("") is foldded into a constant and the function is not
called.
I don't read sh asm that well but it looks like:
mov #0,r1
is wrong, it should be instead:
mov #1, r1
If I changed nanf(") to __builtin_nanf("") on powerpc-darwin, I get:
li r0,1
stw r0,56(r30)
lwz r0,56(r30)
cmpwi cr7,r0,0
So it is doing the correct thing there.
So this still has nothing to do with the nanf prototype really.
--
pinskia at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Summary|const attribute in nanf |__builtin_nanf("") !=
|prototype causes gcc not |__builtin_nanf("") is false
|producing correct code. |for sh4-linux-gnu
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30936
^ permalink raw reply [flat|nested] 9+ messages in thread* [Bug target/30936] __builtin_nanf("") != __builtin_nanf("") is false for sh4-linux-gnu
2007-02-23 15:39 [Bug c/30936] New: const attribute in nanf prototype causes gcc not producing correct code filippo dot arcidiacono at gmail dot com
` (5 preceding siblings ...)
2007-02-26 9:52 ` [Bug target/30936] __builtin_nanf("") != __builtin_nanf("") is false for sh4-linux-gnu pinskia at gcc dot gnu dot org
@ 2007-02-26 13:01 ` filippo dot arcidiacono at gmail dot com
2007-02-26 18:02 ` pinskia at gcc dot gnu dot org
7 siblings, 0 replies; 9+ messages in thread
From: filippo dot arcidiacono at gmail dot com @ 2007-02-26 13:01 UTC (permalink / raw)
To: gcc-bugs
------- Comment #7 from filippo dot arcidiacono at gmail dot com 2007-02-26 13:01 -------
> is wrong, it should be instead:
> mov #1, r1
OK!
This is what I get if I use __builtin_nanf() instead of nanf.
But using nanf there isn't any undefined nanf symbol in the obiect
generated, as expected, as well as happens also with gcc (3.4.3).
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30936
^ permalink raw reply [flat|nested] 9+ messages in thread* [Bug target/30936] __builtin_nanf("") != __builtin_nanf("") is false for sh4-linux-gnu
2007-02-23 15:39 [Bug c/30936] New: const attribute in nanf prototype causes gcc not producing correct code filippo dot arcidiacono at gmail dot com
` (6 preceding siblings ...)
2007-02-26 13:01 ` filippo dot arcidiacono at gmail dot com
@ 2007-02-26 18:02 ` pinskia at gcc dot gnu dot org
7 siblings, 0 replies; 9+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2007-02-26 18:02 UTC (permalink / raw)
To: gcc-bugs
------- Comment #8 from pinskia at gcc dot gnu dot org 2007-02-26 18:02 -------
Actually it turns out this is not a bug but rather you did not read the full
documentation:
http://gcc.gnu.org/onlinedocs/gcc-4.1.0/gcc/SH-Options.html
-mieee
Increase IEEE-compliance of floating-point code. At the moment, this is
equivalent to -fno-finite-math-only. When generating 16 bit SH opcodes, getting
IEEE-conforming results for comparisons of NANs / infinities incurs extra
overhead in every floating point comparison, therefore the default is set to
-ffinite-math-only.
--
pinskia at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|WAITING |RESOLVED
Resolution| |INVALID
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30936
^ permalink raw reply [flat|nested] 9+ messages in thread