[llvm-commits] [llvm] r60608 - in /llvm/trunk: lib/Target/X86/X86ISelLowering.cpp lib/Target/X86/X86Subtarget.cpp lib/Transforms/Scalar/LoopStrengthReduce.cpp test/CodeGen/X86/loop-strength-reduce-2.ll test/CodeGen/X86/loop-strength-reduce-3.ll test/CodeGen/X86/loop-strength-reduce.ll

[Anton Korobeynikov]

Hi, Dale

>
> +/// True if accessing the GV requires a register.  This is a  
> superset of the
> +/// cases where GVRequiresExtraLoad is true.  Some variations of  
> PIC require
> +/// a register, but not an extra load.
> +bool X86Subtarget::GVRequiresRegister(const GlobalValue *GV,
> +                                       const TargetMachine& TM,
> +                                       bool isDirectCall) const
> +{
> +  if (GVRequiresExtraLoad(GV, TM, isDirectCall))
> +    return true;
> +  // Code below here need only consider cases where  
> GVRequiresExtraLoad
> +  // returns false.
> +  if (TM.getRelocationModel() == Reloc::PIC_)
> +    return !isDirectCall &&
> +      (GV->hasInternalLinkage() || GV->hasExternalLinkage());
I don't understand this. Why only internal and external linkage?  
Actually for PIC on Linux (32 bit only) access to every symbols,  
except ones with internal linkage or hidden visibility requires a GOT  
register access. There was even special hook inside  
X86ISelLowering.cpp (incomplete in general, but usable -  
CallRequiresGOTPtrInReg() and another one around) for this sort of  
thing. Please consider using it. We've just ended with 3 hooks used  
for more or less similar stuff.

It will be nice to have all this in one place and in consistent state...

---
With best regards, Anton Korobeynikov
Faculty of Mathematics and Mechanics, Saint Petersburg State University