dotnet clr: Whoops! Sorry, I overlooked the "Console.WriteLine("A Is False")" in the
else clause. Once I add this, I too get the A Is True/A Is False combo in
Release mode, but _not_ Debug.

I've attached my code file to make sure we test using the exact same code,
and so anyone else can reproduce the problem.

Try this: right click the project in the solution explorer -> properties.
Choose "Configuration-->Release" in combo box
Select "Configuration Properties-->Build"
set "Optimize Code" to false

.... and the problem disappears. I don't know why, though.

Scott


[quoted text, click to view]


begin 666 EntryPoint.cs
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F<V4A(BD[#0H@(" @(" @("!]#0H@(" @("!]#0H@("!]#0I]#0H`
`
end

I'm not sure if this helps, but I've decided (for the first time) to dive
into the IL created for this. It seems that the probem is in the IL and not
the JIT (which i'd never understand anyway).

In trying to understand the IL code, I had to go to the msdn library to
figure it all out, so i copied a bit of the docs to make it easier. Note
near the bottom that a "goto" (whatever) is missing to jump over the
Console.WriteLine("A Is False!");

(I'm a veritable newbie at the IL thing, so I apologize if I'm stating the
obvious)

Scott



Here's the IL for Bug2.ctor():



..method public hidebysig specialname rtspecialname
instance void .ctor() cil managed
{
//
// The following is a Release build with
// Optimization = True.
//
// IL documentation comments taken from:
//
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpref/html/frlrfsystemreflectionemitopcodesclassbrfalse_stopic.asp
//
//
// Code size 50 (0x32)
.maxstack 1
.locals init (class ConsoleTest.Bug2/C V_0)
IL_0000: ldarg.0

// Calls the method indicated by the
// passed method descriptor, return
// value pushed onto stack
IL_0001: call instance void [mscorlib]System.Object::.ctor()

// Loads the argument at index 0 onto the evaluation stack.
IL_0006: ldarg.0

// A() pushes "true" onto stack
IL_0007: call instance bool ConsoleTest.Bug2::A()

// Transfers control to a target
// instruction if value is false,
// a null reference, or zero.
IL_000c: brfalse.s IL_0027

IL_000e: ldstr "A Is True!"
IL_0013: call void [mscorlib]System.Console::WriteLine(string)

// pushing an object reference (type O) onto the evaluation stack.
IL_0018: newobj instance void ConsoleTest.Bug2/C::.ctor()

// Pops the current value from top of stack
// and stores it in a the local variable
// list at index 0.
// (object "C" stored at 0.)
IL_001d: stloc.0

// Loads the local variable at index 0
// onto the evaluation stack
// (this is object "C")
IL_001e: ldloc.0

// Transfers control to a target
// instruction if value is false,
// a null reference, or zero.
// (since value is "C", it should be non-null, ie. true.)
IL_001f: brfalse.s IL_0027

// Loads the local variable at index 0
// onto the evaluation stack
// (this is object "C")
IL_0021: ldloc.0

// Calls a late-bound method on an
// object, pushing the return value
// onto the evaluation stack.
IL_0022: callvirt instance void [mscorlib]System.IDisposable::Dispose()

//
//-------------------------------------------------
// It seems that we're missing the "jump" over the
// "A Is False!" WriteLine
//-------------------------------------------------
//
IL_0027: ldstr "A Is False!"
IL_002c: call void [mscorlib]System.Console::WriteLine(string)
IL_0031: ret
} // end of method Bug2::.ctor

Two seconds after sending my previous post, I looked at the IL for an exe
with optimization set to _false_ on a release build.

Near the end of the method, is this little gem:


IL_002a: br.s IL_0036
IL_002c: ldstr "A Is False!"
IL_0031: call void [mscorlib]System.Console::WriteLine(string)
IL_0036: ret
} // end of method Bug2::.ctor

From the msdn docs, br.s means
"Unconditionally transfers control to a target instruction (short form)."

.... just what was missing from the Release w/optimization build.

Scott

[quoted text, click to view]

Doesn't the c# compiler do c# code --> IL?
This is the first step, right?

Scott

Try this in Release mode of .Net 1.1 SP1:

class Bug2
{
class C : IDisposable
{
public C() {}
void IDisposable.Dispose() {}
}

bool A()
{
return true;
}

public Bug2()
{
if (A())
{
Console.WriteLine("A Is True!");
using (new C()) {}
}
else
{
Console.WriteLine("A Is False!");
}
}
}

If i try it in release build (/o+),
i get
A Is True!
A Is False!

[quoted text, click to view]