• Sheff (13/13) Apr 23 2007 Hi!

Sheff <sheffmail mail.ru> writes:

Hi!
I'm porting GDC compiler to QNX (my previous posts related to this topic are:
http://www.digitalmars.com/webnews/newsgroups.php?art_group=digitalmar
.D&article_id=51281 and
http://www.digitalmars.com/webnews/newsgroups.php?art_group=digitalmars.D&article_id=51456)
I'm almost done here, everything is working great, except one little thing:
optimization. It seems to me that -O1, -O2 and -O3 (but not -Os) options
generate bad code. The problem is that the following code doesn't work as
expected:

    char[] a = "abcd";
    char[] r;

    r = a.dup.reverse;
    assert(r == "dcba");

    a = "a\u1235\u1234c";
    r = a.dup.reverse;
    assert(r == "c\u1234\u1235a");

When you compile it without optimization everything is ok, but when you use -O
for example, the following happens:

function _adReverseChar (that's the function that is called when you use
.reverse) works for a very very very long time, that happens because the
"char[] a" parameter that is passed to that function is passed wrongly, if you
call a.length then you'll see that it'll return something like 134_XXX_XXX, i.e
a very large number though the real size of a string is 4.

What could be the problem ? I really don't have a clue, because same code works
fine with -O in linux and QNX is a lot like linux. So it's unlikely that gcc
optimizer works different in linux and qnx, that means that I probably forgot
to turn on/off some switches while compiling GDC, does anyone have any ideas
what exactly could it be ?