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* [Bug rtl-optimization/21223] New: Output register variable is reloaded into the wrong register for asm
@ 2005-04-25 20:49 drow at gcc dot gnu dot org
2005-04-25 20:54 ` [Bug rtl-optimization/21223] " pinskia at gcc dot gnu dot org
` (3 more replies)
0 siblings, 4 replies; 6+ messages in thread
From: drow at gcc dot gnu dot org @ 2005-04-25 20:49 UTC (permalink / raw)
To: gcc-bugs
Compile this test with an ARM-targeted compiler. Using -O2, it works out OK;
but for -O0 or -O1 it doesn't. I originally encountered the bug in -O2 compiled
code, but a more complex testcase is probably necessary for that.
int bar(int *mem)
{
return ({ register int a_oldval asm ("r0");
register int a_tmp asm ("r3");
int a_oldval2 = 3;
__asm__ __volatile__ ("# Should be r0 - %0\n\t"
"# Should be r3 - %1"
: "=&r" (a_oldval), "=&r" (a_tmp)
: "r" (a_oldval2));
a_tmp; });
}
Everything is OK up until reload. Then this happens:
Spilling for insn 19.
Using reg 2 for reload 0
Spilling for insn 19.
Using reg 2 for reload 0
Reloads for insn # 19
Reload 0: reload_out (SI) = (reg/v:SI 3 r3 [ a_tmp ])
GENERAL_REGS, RELOAD_OTHER (opnum = 1)
reload_out_reg: (reg/v:SI 3 r3 [ a_tmp ])
reload_reg_rtx: (reg:SI 2 r2)
and the set of a_tmp is replaced by a set of r2. I can't figure out why
the reload was created.
--
Summary: Output register variable is reloaded into the wrong
register for asm
Product: gcc
Version: 4.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P2
Component: rtl-optimization
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: drow at gcc dot gnu dot org
CC: gcc-bugs at gcc dot gnu dot org
GCC target triplet: arm-none-linux-gnueabi
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21223
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug rtl-optimization/21223] Output register variable is reloaded into the wrong register for asm
2005-04-25 20:49 [Bug rtl-optimization/21223] New: Output register variable is reloaded into the wrong register for asm drow at gcc dot gnu dot org
@ 2005-04-25 20:54 ` pinskia at gcc dot gnu dot org
2005-04-25 21:08 ` drow at gcc dot gnu dot org
` (2 subsequent siblings)
3 siblings, 0 replies; 6+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2005-04-25 20:54 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From pinskia at gcc dot gnu dot org 2005-04-25 20:54 -------
Confirmed, also on powerpc-darwin. Weird.
--
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Ever Confirmed| |1
GCC target triplet|arm-none-linux-gnueabi |arm-none-linux-gnueabi,
| |powerpc-darwin
Keywords| |wrong-code
Known to fail| |3.3.3 4.1.0
Last reconfirmed|0000-00-00 00:00:00 |2005-04-25 20:54:01
date| |
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21223
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug rtl-optimization/21223] Output register variable is reloaded into the wrong register for asm
2005-04-25 20:49 [Bug rtl-optimization/21223] New: Output register variable is reloaded into the wrong register for asm drow at gcc dot gnu dot org
2005-04-25 20:54 ` [Bug rtl-optimization/21223] " pinskia at gcc dot gnu dot org
@ 2005-04-25 21:08 ` drow at gcc dot gnu dot org
2005-04-25 21:10 ` [Bug middle-end/21223] " pinskia at gcc dot gnu dot org
2005-04-25 21:13 ` drow at gcc dot gnu dot org
3 siblings, 0 replies; 6+ messages in thread
From: drow at gcc dot gnu dot org @ 2005-04-25 21:08 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From drow at gcc dot gnu dot org 2005-04-25 21:07 -------
The reload was created because the earlyclobber operand conflicts with
a_oldval2, which is placed in r3 by local-alloc. I think I see why...
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21223
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug middle-end/21223] Output register variable is reloaded into the wrong register for asm
2005-04-25 20:49 [Bug rtl-optimization/21223] New: Output register variable is reloaded into the wrong register for asm drow at gcc dot gnu dot org
2005-04-25 20:54 ` [Bug rtl-optimization/21223] " pinskia at gcc dot gnu dot org
2005-04-25 21:08 ` drow at gcc dot gnu dot org
@ 2005-04-25 21:10 ` pinskia at gcc dot gnu dot org
2005-04-25 21:13 ` drow at gcc dot gnu dot org
3 siblings, 0 replies; 6+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2005-04-25 21:10 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From pinskia at gcc dot gnu dot org 2005-04-25 21:09 -------
And here is an x86 testcase:
int bar(int *mem)
{
return ({ register int a_oldval asm ("eax");
register int a_tmp asm ("ebx");
int a_oldval2 = 3;
__asm__ __volatile__ ("# Should be eax - %0\n\t"
"# Should be ebx - %1\n\t"
"# unknown - %2"
: "=&r" (a_oldval), "=&r" (a_tmp)
: "r" (a_oldval2));
a_tmp; });
}
Which shows this fails at -O2 and above too.
--
What |Removed |Added
----------------------------------------------------------------------------
Component|rtl-optimization |middle-end
GCC target triplet|arm-none-linux-gnueabi, |
|powerpc-darwin |
Known to fail|3.3.3 4.1.0 |3.3.3 4.1.0 2.95.3
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21223
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug middle-end/21223] Output register variable is reloaded into the wrong register for asm
2005-04-25 20:49 [Bug rtl-optimization/21223] New: Output register variable is reloaded into the wrong register for asm drow at gcc dot gnu dot org
` (2 preceding siblings ...)
2005-04-25 21:10 ` [Bug middle-end/21223] " pinskia at gcc dot gnu dot org
@ 2005-04-25 21:13 ` drow at gcc dot gnu dot org
3 siblings, 0 replies; 6+ messages in thread
From: drow at gcc dot gnu dot org @ 2005-04-25 21:13 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From drow at gcc dot gnu dot org 2005-04-25 21:12 -------
The problem is in reg_is_set or its caller.
Because the output is an earlyclobber operand, it needs to be marked as born
before the insn, to conflict with its inputs. I do not see an obvious way to
get from note_stores to the recog alternative.
I reproduced this bug in 3.4.3 (csl-arm-branch) also.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21223
^ permalink raw reply [flat|nested] 6+ messages in thread
[parent not found: <bug-21223-4@http.gcc.gnu.org/bugzilla/>]
end of thread, other threads:[~2021-08-08 21:25 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2005-04-25 20:49 [Bug rtl-optimization/21223] New: Output register variable is reloaded into the wrong register for asm drow at gcc dot gnu dot org
2005-04-25 20:54 ` [Bug rtl-optimization/21223] " pinskia at gcc dot gnu dot org
2005-04-25 21:08 ` drow at gcc dot gnu dot org
2005-04-25 21:10 ` [Bug middle-end/21223] " pinskia at gcc dot gnu dot org
2005-04-25 21:13 ` drow at gcc dot gnu dot org
[not found] <bug-21223-4@http.gcc.gnu.org/bugzilla/>
2021-08-08 21:25 ` pinskia at gcc dot gnu.org
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