[LLVMdev] Fix for non-standard variable length array

[Paolo Invernizzi]

There was a similar problem some time ago, and was resolved with 
alloca. I think it's a better solution to use the stack instead of the 
heap...
---
Paolo Invernizzi

On Oct 18, 2004, at 3:12 PM, Morten Ofstad wrote:

> In lib/CodeGen/LiveVariables.cpp a variable length array is created. 
> Since this is not standard C++, it won't compile with Visual Studio 
> (for interested readers, there is a discussion of why the C99 style 
> variable length array is a bad idea in C++ here: 
> http://www.cuj.com/documents/s=8191/cuj0209stroustr/) I have made a 
> patch that uses 'new' and 'delete' instead - if this is unacceptable 
> for performance reasons, I suggest just choosing some fixed size for 
> the arrays (128 for example) and asserting that the actual number of 
> registers is smaller than this. Patch follows.
>
> On a side note I can now run the fibonacci example with the x86 
> backend compiled with Visual C -- For fun I compiled the fibonacci 
> function also with Visual C with max. optimizes, and the LLVM compiled 
> version is slightly faster! I'm impressed! More patches will follow, 
> sorry for flooding...
>
> m.
>
>
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