K&R defined this very clearly: Arrays are pointers.
Square brackets are syntactic sugar for pointer arithmetic
and dereferencing:
cam_xyz[i][j] vs. *(cam_xyz + (i)*3 + (j))
Whether or not the compiler optimizes a loop out of
existence, it must interpret the contents of the loop no
differently.
Fortunately, GCC 4.9 has no problem abiding this rule.
Dave Coffin 2/27/2015
On Fri, Feb 27, 2015 at 06:02:51PM +0100, conchur@xxxxxx wrote:
> > This sounds like a compiler bug to me. A statement
> > of the form:
> >
> > for (i=0; i < 12; i++) {
> > <code that doesn't change "i">
> > }
> >
> > should never generate an infinite loop.
>
> As seen in https://gcc.gnu.org/bugzilla/show_bug.cgi?id=54136#c5 this
> is hiding something important:
>
> > double cam_xyz[4][3];
>
> The code tries to access it like this:
>
> > cam_xyz[0][j] = table[i].trans[j] / 10000.0;
>
>
> And this is the problem with your code. It just does something
> undefined and happens to get some defined behavior. This is why
> GCC developers marked this problem as invalid and told that the
> code is broken [1].
>
>
> [1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=54136#c5
