[Bug c/35210] New: gcc incorrectly allows calling function returning "const void"

[eli dot friedman at gmail dot com]

const void f(void); void g(void) {f();}

This testcase violates the constraint in C99 6.5.2.2p1 ("The expression that
denotes the called function shall have type pointer to function returning void
or returning an object type other than an array type.", so gcc at the very
least must produce a diagnostic when using -pedantic.  (BTW, is there any code
that depends on this working?)


-- 
   Summary: gcc incorrectly allows calling function returning "const
void"
   Product: gcc
   Version: 4.1.3
Status: UNCONFIRMED
  Severity: normal
  Priority: P3
 Component: c
AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: eli dot friedman at gmail dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35210

[Bug c/35210] gcc incorrectly allows calling function returning "const void"

[eli dot friedman at gmail dot com]

--- Comment #2 from eli dot friedman at gmail dot com  2008-02-15 18:01 
---
Yes, but "const void" is still a distinct type from "void".


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35210

[Bug c/44848] New: Bogus "array subscript is below array bounds" with loops

[eli dot friedman at gmail dot com]

Testcase (derived from ffmpeg):

void av_solve_lls(double (*factor)[33], int count, int min_order){
int i,j,k;
for(i=0; i=0; k--)
sum -= factor[i][k]*factor[j][k];

factor[i][i]= sum;
}
}

for(j=count-1; j>=min_order; j--){
for(i=j; i>=0; i--){
factor[0][j]= 0;
}
factor[0][j] = 0;
for(i=0; i<=j; i++){
factor[0][j] += 0;
}
}
}

With the following command-line:
gcc l.c -S -Wall -O2

Gives the following warning:
/tmp/l.c: In function ‘av_solve_lls’:
/tmp/l.c:18:18: warning: array subscript is below array bounds

Using gcc 4.5.0 on x86-64-pc-linux-gnu, built from source, configured with
"configure --enable-languages=c --disable-bootstrap".

The testcase is a little large, but I can't figure out how to reduce it more;
the issue seems very sensitive to the precise structure of the code.


-- 
   Summary: Bogus "array subscript is below array bounds" with loops
   Product: gcc
   Version: 4.5.0
Status: UNCONFIRMED
  Severity: normal
  Priority: P3
 Component: c
AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: eli dot friedman at gmail dot com
  GCC host triplet: x86-64-pc-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44848

[Bug c/44848] Bogus "array subscript is below array bounds" with loops

[eli dot friedman at gmail dot com]

--- Comment #2 from eli dot friedman at gmail dot com  2010-07-08 03:08 
---
I'm afraid I mis-reduced the issue; try the following (which reproduces on both
trunk r161941 and 4.5.0):

typedef struct LLSModel{
double variance[32];
int indep_count;
}LLSModel;

void av_solve_lls(LLSModel *m, double (*factor)[33], int count, int min_order){
int i,j,k;

for(i=0; i=0; k--)
sum -= factor[i][k];

factor[j][i] = sum;
}
}
for(j=count-1; j>=min_order; j--){
for(i=j; i>=0; i--)
factor[j][i]= 1 / factor[i][i];

m->variance[j]= factor[0][0];
for(i=0; i<=j; i++)
m->variance[j] += factor[j][i];
    }
}


-- 

eli dot friedman at gmail dot com changed:

   What|Removed |Added

 Status|RESOLVED|UNCONFIRMED
 Resolution|DUPLICATE   |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44848