[RESOLVED] [2005] For...Next vs. Do...While

When I open my assemblies in Reflector, my for...next loops are rewritten like so:

Original Loop:

vb.net Code:

For i As Int32 = 0 To 30 Step 1
' Do something
Next i

Rewritten Loop:

vb.net Code:

Dim i As Integer
Do While (i <= 30)
' Do something
i += 1
Loop

I have also seen (and used):

vb.net Code:

Dim i As Integer
Do
' Do something
i += 1
Loop While (i <= 30)

Is there any performance difference between those? Or any difference other than the obvious aesthetic one?

I don't think there should be any significant difference. Although I would recommend using Integer instead of Int32. Because for two reasons:
1. Integer is faster then Int32
2. Integer will work in 64bit system but Int32 will throw an exeption.

Quote:

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Originally Posted by Troy Lundin

Is there any performance difference between those? Or any difference other than the obvious aesthetic one?

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No, that's just how For loops get compiled to bytecode.

Quote:

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Originally Posted by VBDT

1. Integer is faster then Int32

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As far as I know, Integer is mapped to either Int32 or Int64 depending on the platform, so I can't see how this could be true.

Quote:

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Originally Posted by penagate

No, that's just how For loops get compiled to bytecode.



As far as I know, Integer is mapped to either Int32 or Int64 depending on the platform, so I can't see how this could be true.

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Hi penagate, This is from MSDN:

Quote:

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"The Integer data type provides optimal performance on a 32-bit processor. The other integral types are slower to load and store from and to memory."

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Are you positive that the "other integral types" it mentions are not Byte, Short and Long?