http://d.puremagic.com/issues/show_bug.cgi?id=2766

           Summary: DMD hangs with 0%cpu
           Product: D
           Version: 2.026
          Platform: PC
        OS/Version: Windows
            Status: NEW
          Severity: critical
          Priority: P2
         Component: DMD
        AssignedTo: bugzilla@digitalmars.com
        ReportedBy: benoit@tionex.de


compile with "dmd -c t.d"
const byte[] A = [ cast(byte)0 ];
void f( byte* p){
}
void func(){
    f(A.ptr);
}


-- 

http://d.puremagic.com/issues/show_bug.cgi?id=2766





------- Comment #1 from unknown@simplemachines.org  2009-03-29 04:50 -------
Created an attachment (id=299)
 --> (http://d.puremagic.com/issues/attachment.cgi?id=299&action=view)
Potential fix - prevent recursion if optimized type matches.

I'm not sure this is the right solution, but this does solve this problem.

The stack is overflowing (eventually), for some reason this is causing a hang.
It's caused by keyword #1, |const|.  It's trying to cast from const(byte[]) to
byte*.

This seems like something one might see a lot, actually.

What's happening is, |Expression::implicitConvTo()| gets called being
|cast(const(byte)*)cast(const(byte)*)[cast(byte)0]|.  The optimize() call
strips off one of those casts and returns a new |e|, so it calls itself on the
optimized one.  But somehow, that mangy cast gets back in there, and it
recurses endlessly like this.

Visual Studio doesn't show any calls between calls to |Expression::implicitConvTo()|, but I'm not seeing where it is changing. Nonetheless, |e| and |this| are different each time.

However, the purpose of this recursion seems to simply be to properly check the optimized type.  If the optimizer didn't change this type, it hardly seems necessary to recurse.  This also happens in |Expression::implicitCastTo()|.

Still, there is a deeper problem where the cast is doubling up.  This works around the issue (hopefully not incorrectly), but does not solve the root issue.

-[Unknown]


-- 

http://d.puremagic.com/issues/show_bug.cgi?id=2766





------- Comment #2 from bugzilla@digitalmars.com  2009-03-29 16:17 -------
I've got it fixed, so don't worry about it further. -Walter


-- 

http://d.puremagic.com/issues/show_bug.cgi?id=2766


bugzilla@digitalmars.com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |FIXED




------- Comment #3 from bugzilla@digitalmars.com  2009-04-01 13:58 -------
Fixed DMD 2.027


--