[llvm] r225909 - Revert "r225811 - Revert "r225808 - [PowerPC] Add StackMap/PatchPoint support""

[Hal Finkel]

----- Original Message -----
> From: "Hal Finkel" <hfinkel at anl.gov>
> To: "Bill Schmidt" <wschmidt at linux.vnet.ibm.com>
> Cc: llvm-commits at cs.uiuc.edu
> Sent: Thursday, January 15, 2015 10:42:57 PM
> Subject: Re: [llvm] r225909 - Revert "r225811 - Revert "r225808 - [PowerPC]	Add StackMap/PatchPoint support""
> 
> ----- Original Message -----
> > From: "Hal Finkel" <hfinkel at anl.gov>
> > To: "Bill Schmidt" <wschmidt at linux.vnet.ibm.com>
> > Cc: llvm-commits at cs.uiuc.edu
> > Sent: Thursday, January 15, 2015 11:42:36 AM
> > Subject: Re: [llvm] r225909 - Revert "r225811 - Revert "r225808 -
> > [PowerPC]	Add StackMap/PatchPoint support""
> > 
> > ----- Original Message -----
> > > From: "Bill Schmidt" <wschmidt at linux.vnet.ibm.com>
> > > To: "Hal Finkel" <hfinkel at anl.gov>
> > > Cc: llvm-commits at cs.uiuc.edu
> > > Sent: Thursday, January 15, 2015 9:46:05 AM
> > > Subject: Re: [llvm] r225909 - Revert "r225811 - Revert "r225808 -
> > > [PowerPC] Add StackMap/PatchPoint support""
> > > 
> > > Hi Hal,
> > > 
> > > A couple of comments below:
> > 
> > Thanks!
> > 
> > > 
> > > On Wed, 2015-01-14 at 01:07 +0000, Hal Finkel wrote:
> > > 
...
> > > > 
> > > > +const MCPhysReg *
> > > > +PPCTargetLowering::getScratchRegisters(CallingConv::ID) const
> > > > {
> > > > +  // LR is a callee-save register, but we must treat it as
> > > > clobbered by any call
> > > > +  // site. Hence we include LR in the scratch registers, which
> > > > are
> > > > in turn added
> > > > +  // as implicit-defs for stackmaps and patchpoints. The same
> > > > reasoning applies
> > > > +  // to CTR, which is used by any indirect call.
> > > > +  static const MCPhysReg ScratchRegs[] = {
> > > > +    PPC::X11, PPC::X12, PPC::LR8, PPC::CTR8, 0
> > > > +  };
> > > > +
> > > > +  return ScratchRegs;
> > > > +}
> > > 
> > > It isn't safe to assume PPC::X11 is clobbered at an indirect call
> > > site
> > > under the ELFv2 ABI.  The rest of these are ok for both ABIs.
> > 
> > Okay, thanks. I'll update it.
> 
> r226247.

Bill, now I'm somewhat confused. Looking at the ELF V2 spec, R11 is still listed as a volatile register used as an "environment pointer", and so still seems to be available as a scratch register in this sense. Has there really been an ELF V1 -> ELF V2 change w.r.t. R11?

 -Hal

> 
>  -Hal
> 
> > 
> >  -Hal
> > 
> > > 
> > > > +
> > > >  bool
> > > >  PPCTargetLowering::shouldExpandBuildVectorWithShuffles(
> > > >                       EVT VT , unsigned DefinedValues) const {
> > > > 
> > > 
> > > 
> > > 
> > 
> > --
> > Hal Finkel
> > Assistant Computational Scientist
> > Leadership Computing Facility
> > Argonne National Laboratory
> > _______________________________________________
> > llvm-commits mailing list
> > llvm-commits at cs.uiuc.edu
> > http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
> > 
> 
> --
> Hal Finkel
> Assistant Computational Scientist
> Leadership Computing Facility
> Argonne National Laboratory
> _______________________________________________
> llvm-commits mailing list
> llvm-commits at cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
> 

-- 
Hal Finkel
Assistant Computational Scientist
Leadership Computing Facility
Argonne National Laboratory