Re: Can you write code directly in CIL ???


"Peter Olcott" <olcott@xxxxxxx> wrote in message
news:egksf.38007$QW2.25703@xxxxxxxxxxxxx
>
> "Jon Skeet [C# MVP]" <skeet@xxxxxxxxx> wrote in message
> news:MPG.1e1b84c73d78be9098cbe4@xxxxxxxxxxxxxxxxxxxxxxx
>> Nicholas Paldino [.NET/C# MVP] <mvp@xxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
>>> I will second that the C++ compiler is better at optimizing IL
>>> output
>>> than the C# compiler. However, as Willy stated, it will not always
>>> produce
>>> verifiable code... I believe the article you were looking for is in
>>> MSDN
>>> magazine.
>>
>> No, the article was definitely someone posting in this group saying, "I
>> want to be able to embed IL in my C# code, here's why." He then
>> produced some better IL (which I suspect *was* verifiable) which the C#
>> compiler "could" have produced from the source C# (i.e. the behaviour
>> was identical).
>>
>> I'm sure this will improve over time, but to be honest it's usually the
>> JIT that has more to do with optimisation IMO.
>
> I wouldn't think that this would be the case for two reasons:
> (1) CIL (for the most part) forms a one-to-one mapping with assembly
> language

Not true, IL is kind of high level language compared to X86 assembly, one
single IL instruction translates to x assembly level instructions where x is
certainly not 1.

> (2) End users are waiting on the JIT to complete, no time to waste doing
> optimizations that could have been done before the softwae shipped.
>

Wrong again, IL is not optimized that much, THE optimizer is the JIT. It's
the JIT that knows at run-time what kind of optmizations can be performed
depending on the characteristics of the HW like CPU type 32bit/64 bit,
number of registers, L1 and L2 cache sizes, MMX/SSE enabled etc.
The CLR is a run-time optimizing execution engine, whether you believe it or
not.


Willy.


.

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