[LLVMdev] Implementing llvm.memory.barrier on PowerPC

[Gary Benson]

No, I don't.

Cheers,
Gary

Dale Johannesen wrote:
> This looks OK to check in, do you have write access?
> 
> On Aug 21, 2008, at 6:38 AMPDT, Gary Benson wrote:
> 
> >Dale Johannesen wrote:
> >>On Aug 19, 2008, at 7:18 AMPDT, Gary Benson wrote:
> >>>I'm trying to implement llvm.memory.barrier on PowerPC.  I've
> >>>modelled my patch (attached) on the implementation in X86, but
> >>>when I try and compile my test file (also attached) with llc I
> >>>get the error "Cannot yet select: 0x10fa4ad0: ch = MemBarrier
> >>>0x10fa4828, 0x10fa4c68, 0x10fa4be0, 0x10fa4be0, 0x10fa4be0,
> >>>0x10fa4be0".  This presumably means my "membarrier" pattern
> >>>isn't being found... but why?
> >>
> >>Because the i1's in the .bc file get promoted to i32 on ppc,
> >>instead of i8.  I've forgotten why this is, there's a setting
> >>somewhere.  If you change the i8's in membarrier to i32's it
> >>works.
> >
> >Thanks for that.  Attached is a working implementation of
> >llvm.memory.barrier.
> >
> >>Thanks for doing this btw.
> >
> >No problem, I need it! ;)
> >
> >Cheers,
> >Gary
> >
> >-- 
> >http://gbenson.net/

> Index: include/llvm/IntrinsicsPowerPC.td
> ===================================================================
> --- include/llvm/IntrinsicsPowerPC.td	(revision 54985)
> +++ include/llvm/IntrinsicsPowerPC.td	(working copy)
> @@ -26,6 +26,9 @@
>    def int_ppc_dcbtst: Intrinsic<[llvm_void_ty, llvm_ptr_ty], [IntrWriteMem]>;
>    def int_ppc_dcbz  : Intrinsic<[llvm_void_ty, llvm_ptr_ty], [IntrWriteMem]>;
>    def int_ppc_dcbzl : Intrinsic<[llvm_void_ty, llvm_ptr_ty], [IntrWriteMem]>;
> +
> +  // sync instruction
> +  def int_ppc_sync : Intrinsic<[llvm_void_ty], [IntrWriteMem]>;
>  }
>  
>  
> Index: lib/Target/PowerPC/PPCInstrInfo.td
> ===================================================================
> --- lib/Target/PowerPC/PPCInstrInfo.td	(revision 54985)
> +++ lib/Target/PowerPC/PPCInstrInfo.td	(working copy)
> @@ -773,6 +773,10 @@
>                       [(store F8RC:$frS, xaddr:$dst)]>;
>  }
>  
> +let isBarrier = 1 in
> +def SYNC : XForm_24_sync<31, 598, (outs), (ins),
> +                        "sync", LdStSync,
> +                        [(int_ppc_sync)]>;
>  
>  //===----------------------------------------------------------------------===//
>  // PPC32 Arithmetic Instructions.
> @@ -1357,5 +1361,13 @@
>  def : Pat<(extloadf32 xaddr:$src),
>            (FMRSD (LFSX xaddr:$src))>;
>  
> +// Memory barriers
> +def : Pat<(membarrier (i32 imm:$ll),
> +                      (i32 imm:$ls),
> +                      (i32 imm:$sl),
> +                      (i32 imm:$ss),
> +                      (i32 imm:$device)),
> +           (SYNC)>;
> +
>  include "PPCInstrAltivec.td"
>  include "PPCInstr64Bit.td"
> Index: lib/Target/PowerPC/PPCISelLowering.cpp
> ===================================================================
> --- lib/Target/PowerPC/PPCISelLowering.cpp	(revision 54985)
> +++ lib/Target/PowerPC/PPCISelLowering.cpp	(working copy)
> @@ -78,9 +78,6 @@
>    // from FP_ROUND:  that rounds to nearest, this rounds to zero.
>    setOperationAction(ISD::FP_ROUND_INREG, MVT::ppcf128, Custom);
>  
> -  // PowerPC has no intrinsics for these particular operations
> -  setOperationAction(ISD::MEMBARRIER, MVT::Other, Expand);
> -
>    // PowerPC has no SREM/UREM instructions
>    setOperationAction(ISD::SREM, MVT::i32, Expand);
>    setOperationAction(ISD::UREM, MVT::i32, Expand);
> Index: lib/Target/PowerPC/PPCInstrFormats.td
> ===================================================================
> --- lib/Target/PowerPC/PPCInstrFormats.td	(revision 54985)
> +++ lib/Target/PowerPC/PPCInstrFormats.td	(working copy)
> @@ -309,6 +309,17 @@
>    let Inst{31}    = 0;
>  }
>  
> +class XForm_24_sync<bits<6> opcode, bits<10> xo, dag OOL, dag IOL,
> +               string asmstr, InstrItinClass itin, list<dag> pattern> 
> +  : I<opcode, OOL, IOL, asmstr, itin> {
> +  let Pattern = pattern;
> +  let Inst{6-10}  = 0;
> +  let Inst{11-15} = 0;
> +  let Inst{16-20} = 0;
> +  let Inst{21-30} = xo;
> +  let Inst{31}    = 0;
> +}
> +
>  class XForm_25<bits<6> opcode, bits<10> xo, dag OOL, dag IOL, string asmstr,
>                 InstrItinClass itin, list<dag> pattern> 
>    : XForm_base_r3xo<opcode, xo, OOL, IOL, asmstr, itin, pattern> {

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