[LLVMdev] "Best" alias analysis algorithm

Chris Lattner sabre at nondot.org
Mon Apr 25 08:48:20 PDT 2005

On Mon, 25 Apr 2005, Vladimir Prus wrote:
> On Monday 25 April 2005 14:43, Vladimir Prus wrote:
> The GlobalsModRef::getModRefInfo has this logic:
>    // If we are asking for mod/ref info of a direct call with a pointer to a
>    // global we are tracking, return information if we have it.
>    if (GlobalValue *GV = const_cast<GlobalValue*>(getUnderlyingObject(P)))
>       if (GV->hasInternalLinkage())
> So, no information is produced for external variables, the function calls
> Aliasanalysis::getModRefInfo, which sees that called function may write to
> memory, and returns true for all global variables.
> Anything I can do about it? What I what is minimally accurate information
> about all global variables a function may modify. "Modifies them all" is
> clearly not even minimally accurate.

I will take a look at this and fix globals-modref.  This is definitely 
over conservative!  Thanks for pointing it out!



More information about the llvm-dev mailing list