[LLVMdev] GSoC - Range Analysis

[Duncan Sands]

Hi John,

> Regarding your comment about Java, I think you're correct that your
> range analysis would be better at optimizing Java code.  However, LLVM
> really isn't used for Java, so I'm not sure if that's a strong argument
> for your proposal.  To get the best bang for the buck, I think your
> analysis will need to work well in optimizing C/C++/Objective-C[++] code.

I use LLVM for compiling Ada.  Ada turns into LLVM IR which is chock-a-block
full of range checks, so this analysis might be helpful for Ada.

> One thing you could do to mitigate that problem is to do an experiment
> that *shows* that your analysis has the potential to find more
> optimization opportunities than what LLVM does today.  For example, for
> dead code elimination, you could run your analysis on optimized LLVM
> bitcode and find the percentage of icmp/fcmp instructions that can be
> changed into constants.  If you find a large percentage, then it is more
> likely that your analysis will help dead code elimination or other
> optimizations.

In short, if you can speed up important programs using your analysis then that
would be a great selling point.

Ciao, Duncan.