[Bug c/22346] New: Miscompilation (infinite loop longjmp?)
I really hope this is a bug in my code and not a gcc bug otherwise it looks
serious. The problem basically is that we have an infinite for(;;) loop which
calls a function and adds its return value to a local variable 'sum'.
The loop is terminated with a longjmp.
If the program is compiled at -O0 everything is ok and 'sum' has the sum.
If compiled with -O1 the sum is always zero.
If we enable a printf printing the value of sum in each iteration, the
result is correct.
The reduced testcase is this:
/
/* lightweight c++ 1.4 */
/** system headers **/
#include stdio.h
#include setjmp.h
/** global scope **/
struct A;
/** Structures **/
struct A_ViRtUaLTaBlE_StRuCt {
int (*next_APSA1_virtual) (struct A * const this);
};
struct A {
int c;
struct A_ViRtUaLTaBlE_StRuCt *const _v_p_t_r_;
};
struct AuToDt_t {
const struct AuToDt_t *X;
void *x;
void *(*y) (void *);
};
struct longjmp_StaCk {
jmp_buf *x;
struct longjmp_StaCk *y;
void *X;
const struct AuToDt_t *i;
};
/** Virtua Table declarations **/
static struct A_ViRtUaLTaBlE_StRuCt A_A_ViRtUaLTaBlE;
/* Function Prototypes /
static inline void A_ctor_(struct A *const this);
static inline int A_next_(struct A *const this);
void *malloc(unsigned int);
void free();
/* Global variables **/
struct longjmp_StaCk longjmp_iNiTObjFaKe, *__restrict longjmp_StaCkTop =
longjmp_iNiTObjFaKe;
void __lwc_unwind(void *) __attribute__ ((noreturn));
void __lwc_unwind(void *X)
{
longjmp_StaCkTop-X = X;
while (longjmp_StaCkTop-i) {
longjmp_StaCkTop-i-y(longjmp_StaCkTop-i-x);
longjmp_StaCkTop-i = longjmp_StaCkTop-i-X;
}
longjmp(*longjmp_StaCkTop-x, 1);
}
static inline void *__lwcbuiltin_get_estack()
{
return longjmp_StaCkTop;
}
static inline void __lwcbuiltin_set_estack(void *v)
{
longjmp_StaCkTop = v;
}
/ Internal Functions */
static inline void A___ICoNsTRuCTion(struct A *x, const int y)
{
int i;
for (i = 0; i y; i++) {
struct A *X = x[i];
*(struct A_ViRtUaLTaBlE_StRuCt * *) X-_v_p_t_r_ = A_A_ViRtUaLTaBlE;
}
}
static inline int next_APSA1_virtual(struct A *const this)
{
return this-_v_p_t_r_-next_APSA1_virtual(this);
}
/* Program function definitions */
static inline void A_ctor_(struct A *const this)
{
this-c = 0;
}
static inline int A_next_(struct A *const this)
{
if (this-c 10)
__lwc_unwind(0);
return this-c++;
}
int main()
{
struct A *a = ({
struct A * lwcUniQUe = (struct A *)malloc(sizeof(struct A));
A___ICoNsTRuCTion(lwcUniQUe, 1); A_ctor_(lwcUniQUe);
lwcUniQUe;}
);
int sum = 0;
{
struct longjmp_StaCk longjmp_CoNtExT;
jmp_buf lwcUniQUe2;
longjmp_CoNtExT.x = lwcUniQUe2;
longjmp_CoNtExT.y = longjmp_StaCkTop;
longjmp_StaCkTop = longjmp_CoNtExT;
longjmp_CoNtExT.X = 0;
longjmp_CoNtExT.i = 0;
if (!(setjmp(lwcUniQUe2))) {
{
for (;;) {
sum += next_APSA1_virtual(a);
// printf(sum=%i\n, sum);
}
}
longjmp_StaCkTop = longjmp_CoNtExT.y;
} else {
longjmp_StaCkTop = longjmp_CoNtExT.y;
}
}
printf(%i\n, sum);
return 0;
}
/ Virtual tables /
static struct A_ViRtUaLTaBlE_StRuCt A_A_ViRtUaLTaBlE = { .next_APSA1_virtual =
A_next_,} ;
///
--
Summary: Miscompilation (infinite loop longjmp?)
Product: gcc
Version: 3.4.4
Status: UNCONFIRMED
Severity: normal
Priority: P2
Component: c
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: sxanth at ceid dot upatras dot gr
CC: gcc-bugs at gcc dot gnu dot org
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=22346
[Bug c/20161] New: ICE with dwarf for incomplete element type argument
First of all the typescript: ## [EMAIL PROTECTED]:~/wtmp cat gb.c struct XX; typedef void *(*F) (struct XX []); [EMAIL PROTECTED]:~/wtmp CVSgcc gb.c -Wall -g gb.c:3: error: array type has incomplete element type gb.c:3: internal compiler error: in gen_formal_parameter_die, at dwarf2out.c:11062 Please submit a full bug report, with preprocessed source if appropriate. See URL:http://gcc.gnu.org/bugs.html for instructions. [EMAIL PROTECTED]:~/wtmp CVSgcc -v Using built-in specs. Target: i686-pc-linux-gnu Configured with: ../configure --prefix=/home/stan/GCC/gcc-4.0-20050220/bin --program-prefix=CVS : (reconfigured) ../configure --prefix=/home/stan/GCC/gcc-4.0-20050220/bin --program-prefix=CVS Thread model: posix gcc version 4.0.0 20050220 (experimental) ## Except from the internal compiler error, is it a bug that gcc considers the incomplete type an error? If yes, then this is even more critical. In 3.4 and 3.2 the above code was Ok. -- Summary: ICE with dwarf for incomplete element type argument Product: gcc Version: 4.0.0 Status: UNCONFIRMED Severity: normal Priority: P2 Component: c AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: sxanth at ceid dot upatras dot gr CC: gcc-bugs at gcc dot gnu dot org http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20161
[Bug c/20167] New: static inlines discared while needed by alias
typescript of the problem:
##
[EMAIL PROTECTED]:~/wtmp cat gb2.c
static inline int foo ()
{
return 123;
}
static inline int bar () __attribute__ ((alias (foo)));
int main ()
{
return bar ();
}
[EMAIL PROTECTED]:~/wtmp CVSgcc gb2.c
/tmp/ccWI7qQj.o: In function `main':
/tmp/ccWI7qQj.o(.text+0x1d): undefined reference to `foo'
collect2: ld returned 1 exit status
[EMAIL PROTECTED]:~/wtmp CVSgcc -v
Using built-in specs.
Target: i686-pc-linux-gnu
Configured with: ../configure --prefix=/home/stan/GCC/gcc-4.0-20050220/bin
--program-prefix=CVS : (reconfigured) ../configure
--prefix=/home/stan/GCC/gcc-4.0-20050220/bin --program-prefix=CVS
Thread model: posix
gcc version 4.0.0 20050220 (experimental)
###
Seems to discard the function because it thinks it's unused.
--
Summary: static inlines discared while needed by alias
Product: gcc
Version: 4.0.0
Status: UNCONFIRMED
Severity: normal
Priority: P2
Component: c
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: sxanth at ceid dot upatras dot gr
CC: gcc-bugs at gcc dot gnu dot org
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20167
[Bug tree-optimization/9079] [tree-ssa] Inline constant function pointers
--- Additional Comments From sxanth at ceid dot upatras dot gr 2004-12-13
22:25 ---
This is present in 3.4 too
static inline int foo ()
{
return 100;
}
typedef int (*fptr)();
static const fptr a [] = { foo };
static inline int call (int i)
{
return a [i]();
}
static inline int call2 (fptr f)
{
return f();
}
static const fptr F = foo;
int main ()
{
return call (0) + call2 (foo) + F() +foo();
}
---
Here only F() and foo() are added at compile time
but it would be better if gcc just returned 400 w/o any other code.
Please fix!
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=9079
