[nem-bug] [Nemerle 0000828]: Mono doesn't implement conv.ovf.u4.un; Nemerle generates it

[feedback at nemerle.org]

The following issue requires your FEEDBACK.
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<http://nemerle.org/bugs/view.php?id=828> 
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Reported By:                Evin Robertson
Assigned To:                
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Project:                    Nemerle
Issue ID:                   828
Category:                   Compiler
Reproducibility:            always
Severity:                   minor
Priority:                   normal
Status:                     feedback
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Date Submitted:             01-19-2007 02:45 CET
Last Modified:              01-19-2007 17:58 CET
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Summary:                    Mono doesn't implement conv.ovf.u4.un; Nemerle
generates it
Description: 
Mono doesn't implement conv.ovf.u4.un.  See
http://bugzilla.ximian.com/show_bug.cgi?id=70355 where this is marked
WONTFIX.

Nemerle generates this opcode on code like the following:

def x = '\n' :> uint
def y = (0 : ushort) :> uint

These casts could never fail, so they don't need to be checked for
overflow.  Attached is a patch to generate the unchecked opcode instead.

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----------------------------------------------------------------------
 nazgul - 01-19-07 17:57 
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I checked with mono (Mono JIT compiler version 1.2.2) and it generates the
same opcode, which works very well:

[nazgul at lilith ~]$ mono --version
Mono JIT compiler version 1.2.2, (C) 2002-2006 Novell, Inc and
Contributors. www.mono-project.com
        TLS:           normal
        GC:            Included Boehm (with typed GC)
        SIGSEGV:       normal
        Disabled:      none
[nazgul at lilith ~]$ cat t.cs 
class A {
static void Main () {
ulong x = ulong.MaxValue;
uint y = 33;
y = (uint) x;
}
}
[nazgul at lilith ~]$ mcs t.cs /checked
t.cs(4,6): warning CS0219: The variable `y' is assigned but its value is
never used
Compilation succeeded - 1 warning(s)
[nazgul at lilith ~]$ ./t.exe 

Unhandled Exception: System.OverflowException: Number overflow.
  at A.Main () [0x00000] 
[nazgul at lilith ~]$ monodis t.exe | grep conv.ovf.u4.un
        IL_0007:  conv.ovf.u4.un 


Note that ncc runs in /checked mode by default. 

The bugreport you refer to looks quite old, probably they changed their
mind and implemented the opcode, since it is needed (e.g. in above
program)

----------------------------------------------------------------------
 nazgul - 01-19-07 17:58 
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Which version of mono do you use? I guess we should close it as NOTABUG

Issue History
Date Modified  Username       Field                    Change              
======================================================================
01-19-07 02:45 Evin Robertson New Issue                                    
01-19-07 02:45 Evin Robertson File Added: conv_u4.patch                    
01-19-07 17:57 nazgul         Note Added: 0001610                          
01-19-07 17:58 nazgul         Note Added: 0001611                          
01-19-07 17:58 nazgul         Status                   new => feedback     
01-19-07 17:58 nazgul         Summary                  Mono doesn't implement
conv.ovf.u4.un; Nemerle generates it => Mono doesn\'t implement conv.ovf.u4.un;
Nemerle generates it
01-19-07 17:58 nazgul         Description Updated                          
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