[llvm] r177011 - Teach X86 MC instruction lowering that VMOVAPSrr and other VEX-encoded register to register moves should be switched from using the MRMSrcReg form to the MRMDestReg form if the source register is a 64-bit extended register and the destination register is not. This allows the instruction to be encoded using the 2-byte VEX form instead of the 3-byte VEX form. The GNU assembler has similar behavior.

Michael Liao michael.liao at intel.com
Fri Mar 15 18:43:23 PDT 2013


Here is the revised patch. VMOVSS/VMOVSD should check operand 0 and 2
and operand 1 is encoded in VEX.vvvv.

Yours
- Michael

On Fri, 2013-03-15 at 18:32 -0700, Michael Liao wrote:
> Hi Craig
> 
> It's turned out that VEX.vvvv is not supported in DstReg form. I add
> quick fix to that. It won't crash during code emission on VMOVSS. Test
> case is added as well. Please have a look.
> 
> Yours
> - Michael
> 
> On Fri, 2013-03-15 at 15:38 -0700, Craig Topper wrote:
> > What assertion is failing?
> > 
> > On Fri, Mar 15, 2013 at 2:31 PM, Nadav Rotem <nrotem at apple.com> wrote:
> >         Hi Craig, 
> >         
> >         
> >         This commit causes an assertion failure in the X86 code
> >         emitter and one of the build bots is failing. I attached a
> >         test case.
> >         
> >         
> >         
> >         
> >         
> >         
> >         
> >         Thanks,
> >         - Nadav
> >         
> >         
> >         
> >         On Mar 14, 2013, at 12:09 AM, Craig Topper
> >         <craig.topper at gmail.com> wrote:
> >         
> >         > Author: ctopper
> >         > Date: Thu Mar 14 02:09:57 2013
> >         > New Revision: 177011
> >         > 
> >         > URL: http://llvm.org/viewvc/llvm-project?rev=177011&view=rev
> >         > Log:
> >         > Teach X86 MC instruction lowering that VMOVAPSrr and other
> >         > VEX-encoded register to register moves should be switched
> >         > from using the MRMSrcReg form to the MRMDestReg form if the
> >         > source register is a 64-bit extended register and the
> >         > destination register is not. This allows the instruction to
> >         > be encoded using the 2-byte VEX form instead of the 3-byte
> >         > VEX form. The GNU assembler has similar behavior.
> >         > 
> >         > Modified:
> >         >    llvm/trunk/lib/Target/X86/X86MCInstLower.cpp
> >         > 
> >         > Modified: llvm/trunk/lib/Target/X86/X86MCInstLower.cpp
> >         > URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86MCInstLower.cpp?rev=177011&r1=177010&r2=177011&view=diff
> >         > ==============================================================================
> >         > --- llvm/trunk/lib/Target/X86/X86MCInstLower.cpp (original)
> >         > +++ llvm/trunk/lib/Target/X86/X86MCInstLower.cpp Thu Mar 14
> >         > 02:09:57 2013
> >         > @@ -407,6 +407,48 @@ ReSimplify:
> >         >     LowerUnaryToTwoAddr(OutMI, X86::XOR32rr); // MOV32r0 ->
> >         > XOR32rr
> >         >     break;
> >         > 
> >         > +  // Commute operands to get a smaller encoding by using
> >         > VEX.R instead of VEX.B
> >         > +  // if one of the registers is extended, but other isn't.
> >         > +  case X86::VMOVAPDrr:
> >         > +  case X86::VMOVAPDYrr:
> >         > +  case X86::VMOVAPSrr:
> >         > +  case X86::VMOVAPSYrr:
> >         > +  case X86::VMOVDQArr:
> >         > +  case X86::VMOVDQAYrr:
> >         > +  case X86::VMOVDQUrr:
> >         > +  case X86::VMOVDQUYrr:
> >         > +  case X86::VMOVSDrr:
> >         > +  case X86::VMOVSSrr:
> >         > +  case X86::VMOVUPDrr:
> >         > +  case X86::VMOVUPDYrr:
> >         > +  case X86::VMOVUPSrr:
> >         > +  case X86::VMOVUPSYrr: {
> >         > +    if
> >         > (X86II::isX86_64ExtendedReg(OutMI.getOperand(0).getReg()) &&
> >         > +        !
> >         > X86II::isX86_64ExtendedReg(OutMI.getOperand(1).getReg()))
> >         > +      break;
> >         > +
> >         > +    unsigned NewOpc;
> >         > +    switch (OutMI.getOpcode()) {
> >         > +    default: llvm_unreachable("Invalid opcode");
> >         > +    case X86::VMOVAPDrr:  NewOpc = X86::VMOVAPDrr_REV;
> >         >  break;
> >         > +    case X86::VMOVAPDYrr: NewOpc = X86::VMOVAPDYrr_REV;
> >         > break;
> >         > +    case X86::VMOVAPSrr:  NewOpc = X86::VMOVAPSrr_REV;
> >         >  break;
> >         > +    case X86::VMOVAPSYrr: NewOpc = X86::VMOVAPSYrr_REV;
> >         > break;
> >         > +    case X86::VMOVDQArr:  NewOpc = X86::VMOVDQArr_REV;
> >         >  break;
> >         > +    case X86::VMOVDQAYrr: NewOpc = X86::VMOVDQAYrr_REV;
> >         > break;
> >         > +    case X86::VMOVDQUrr:  NewOpc = X86::VMOVDQUrr_REV;
> >         >  break;
> >         > +    case X86::VMOVDQUYrr: NewOpc = X86::VMOVDQUYrr_REV;
> >         > break;
> >         > +    case X86::VMOVSDrr:   NewOpc = X86::VMOVSDrr_REV;
> >         >   break;
> >         > +    case X86::VMOVSSrr:   NewOpc = X86::VMOVSSrr_REV;
> >         >   break;
> >         > +    case X86::VMOVUPDrr:  NewOpc = X86::VMOVUPDrr_REV;
> >         >  break;
> >         > +    case X86::VMOVUPDYrr: NewOpc = X86::VMOVUPDYrr_REV;
> >         > break;
> >         > +    case X86::VMOVUPSrr:  NewOpc = X86::VMOVUPSrr_REV;
> >         >  break;
> >         > +    case X86::VMOVUPSYrr: NewOpc = X86::VMOVUPSYrr_REV;
> >         > break;
> >         > +    }
> >         > +    OutMI.setOpcode(NewOpc);
> >         > +    break;
> >         > +  }
> >         > +
> >         >   // TAILJMPr64, CALL64r, CALL64pcrel32 - These instructions
> >         > have register
> >         >   // inputs modeled as normal uses instead of implicit
> >         > uses.  As such, truncate
> >         >   // off all but the first operand (the callee).  FIXME:
> >         > Change isel.
> >         > 
> >         > 
> >         > _______________________________________________
> >         > llvm-commits mailing list
> >         > llvm-commits at cs.uiuc.edu
> >         > http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
> >         
> >         
> >         
> > 
> > 
> > 
> > 
> > -- 
> > ~Craig 
> > _______________________________________________
> > llvm-commits mailing list
> > llvm-commits at cs.uiuc.edu
> > http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
> 
> _______________________________________________
> llvm-commits mailing list
> llvm-commits at cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits

-------------- next part --------------
A non-text attachment was scrubbed...
Name: 0001-Add-VEX.vvvv-support-for-DstReg-form.patch
Type: text/x-patch
Size: 5557 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20130315/84742e2b/attachment.bin>


More information about the llvm-commits mailing list