[Bug c/33374] New: GCC 4.1.2 produce wrong assembler code with -O2 option enabled.

[_kirpichev_ at mail dot ru]

I use gcc 4.1.2 under solaris and linux and compile code using next commands:
Linux:
gcc -pipe -Wall -Wextra -Winvalid-pch -ansi -pedantic -Wundef -Wc++-compat
-Wfloat-equal -Wredundant-decls -Waggregate-return -Wbad-function-cast
-Wmissing-declarations -Wmissing-prototypes -Wstrict-prototypes -Wcast-align
-Wshadow -Wsign-compare -Wnested-externs -Wcast-qual -Wpointer-arith
-Wdeclaration-after-statement -Werror -O2 -finline-functions
-Wdisabled-optimization -DNDEBUG test.c -o mtest_l

Solaris:
gcc -pipe -Wall -Wextra -Winvalid-pch -ansi -pedantic -Wundef -Wc++-compat
-Wfloat-equal -Wredundant-decls -Waggregate-return -Wbad-function-cast
-Wstrict-prototypes -Wcast-align -Wshadow -Wsign-compare -Wnested-externs
-Wcast-qual -Wpointer-arith -Wdeclaration-after-statement -Werror -O2
-finline-functions -Wdisabled-optimization -DNDEBUG -g -o mtest test.c

Segmentation fault happens when I try to run test program (see test.c
attached).


-- 
   Summary: GCC 4.1.2 produce wrong assembler code with -O2 option
enabled.
   Product: gcc
   Version: 4.1.2
Status: UNCONFIRMED
  Severity: critical
  Priority: P3
 Component: c
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: _kirpichev_ at mail dot ru


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33374

[Bug c/33374] GCC 4.1.2 produce wrong assembler code with -O2 option enabled.

[_kirpichev_ at mail dot ru]

--- Comment #1 from _kirpichev_ at mail dot ru  2007-09-10 07:45 ---
Created an attachment (id=14182)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=14182&action=view)
test programm

This example is compiled incorrectly by gcc 4.1.2 with -O2 flag.
But all works fine if we change line 93 in this example on next:
XML_Remove(currNode_sp);


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33374

[Bug c/33374] GCC 4.1.2 produce wrong assembler code with -O2 option enabled.

[_kirpichev_ at mail dot ru]

--- Comment #2 from _kirpichev_ at mail dot ru  2007-09-10 07:53 ---
Created an attachment (id=14183)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=14183&action=view)
Correct and incorrect assembler dumps.

>From incorrect dump we can see where segmentation fault heppens:

0x0804839e :   movDWORD PTR [ecx+4],0x0
0x080483a5 :   movDWORD PTR [eax+4],edx
0x080483a8 :   movedx,DWORD PTR [ecx+4]
0x080483ab :   movecx,ebx
0x080483ad :   movDWORD PTR [edx],eax

Instruction 0x080483ad tries to dereferencing pointer in edx, but
in edx zero was put by 0x080483a8.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33374

[Bug target/33374] GCC 4.1.2 produce wrong assembler code with -O2 option enabled.

[_kirpichev_ at mail dot ru]

--- Comment #4 from _kirpichev_ at mail dot ru  2007-09-10 08:53 ---
There is no core dump with -fno-strict-aliasing.
But, our code is used by others who can not set this option.
Should code compiled without -fno-strict-aliasing produce core dump?
In my opinion, the best way is produce only compiliation warnings in this case.

Should we rewrite our code if it is not possible to set -fno-strict-aliasing
option, or it is gcc issue that fixed in other versions?


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33374

[Bug c/46477] New: GCC doesn't understand %c in asm instruction with -mcmodel=large

[_kirpichev_ at mail dot ru]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46477

   Summary: GCC doesn't understand %c in asm instruction with
-mcmodel=large
   Product: gcc
   Version: 4.5.0
Status: UNCONFIRMED
  Severity: normal
  Priority: P3
 Component: c
AssignedTo: unassig...@gcc.gnu.org
ReportedBy: _kirpich...@mail.ru


Hi,

I'm trying to compile the following code snippet:
#ifdef CONFIG_X86_32
# define __BUG_C0   "2:\t.long 1b, %c0\n"
#else
# define __BUG_C0   "2:\t.long 1b - 2b, %c0 - 2b\n"
#endif

#define BUG()   \
do {\
asm volatile("1:\tud2\n"\
".pushsection __bug_table,\"a\"\n" \
__BUG_C0   \
"\t.word %c1, 0\n" \
"\t.org 2b+%c2\n"  \
".popsection"  \
: : "i" (__FILE__), "i" (__LINE__),\
"i" (10*sizeof(int)));   \
} while (0)

int main()
{
BUG();
}

And everything is ok until -mcmodel=large is used.

When I'm trying to use -mcmodel=large the following error appears:

main.c:24:9: error: invalid 'asm': operand is neither a constant nor a
condition code, invalid operand code 'c'

gcc -dumpversion
4.5


BTW, if I change %c on %P then everything is ok and generated code looks the
same, but I didn't find any documentation about %P.