[PATCH] AMDGPU/SI: Don't set DATA_FORMAT if ADD_TID_ENABLE is set

[Tom Stellard via llvm-commits]

On Tue, Sep 29, 2015 at 04:56:53PM +0200, Marek Olšák via llvm-commits wrote:
> From: Marek Olšák <marek.olsak at amd.com>
> 
> to prevent setting a huge stride, because DATA_FORMAT has a different
> meaning if ADD_TID_ENABLE is set.
> 
> This is a candidate for stable llvm 3.7.
> ---
>  lib/Target/AMDGPU/SIISelLowering.cpp       |  4 +---
>  lib/Target/AMDGPU/SIInstrInfo.cpp          | 14 ++++++++++++++
>  lib/Target/AMDGPU/SIInstrInfo.h            |  2 +-
>  lib/Target/AMDGPU/SIPrepareScratchRegs.cpp |  7 +++----
>  4 files changed, 19 insertions(+), 8 deletions(-)
> 
> diff --git a/lib/Target/AMDGPU/SIISelLowering.cpp b/lib/Target/AMDGPU/SIISelLowering.cpp
> index 0bae789..b4b439c 100644
> --- a/lib/Target/AMDGPU/SIISelLowering.cpp
> +++ b/lib/Target/AMDGPU/SIISelLowering.cpp
> @@ -2257,10 +2257,8 @@ MachineSDNode *SITargetLowering::buildScratchRSRC(SelectionDAG &DAG,
>                                                    SDValue Ptr) const {
>    const SIInstrInfo *TII =
>        static_cast<const SIInstrInfo *>(Subtarget->getInstrInfo());
> -  uint64_t Rsrc = TII->getDefaultRsrcDataFormat() | AMDGPU::RSRC_TID_ENABLE |
> -                  0xffffffff; // Size
>  
> -  return buildRSRC(DAG, DL, Ptr, 0, Rsrc);
> +  return buildRSRC(DAG, DL, Ptr, 0, TII->getScratchRsrcWords23());
>  }
>  
>  SDValue SITargetLowering::CreateLiveInRegister(SelectionDAG &DAG,
> diff --git a/lib/Target/AMDGPU/SIInstrInfo.cpp b/lib/Target/AMDGPU/SIInstrInfo.cpp
> index b667dc2..7b10f32 100644
> --- a/lib/Target/AMDGPU/SIInstrInfo.cpp
> +++ b/lib/Target/AMDGPU/SIInstrInfo.cpp
> @@ -2781,3 +2781,17 @@ uint64_t SIInstrInfo::getDefaultRsrcDataFormat() const {
>  
>    return RsrcDataFormat;
>  }
> +
> +uint64_t SIInstrInfo::getScratchRsrcWords23() const {
> +  uint64_t Rsrc23 = getDefaultRsrcDataFormat() |
> +                    AMDGPU::RSRC_TID_ENABLE |
> +                    0xffffffff; // Size;
> +
> +  /* If TID_ENABLE is set, DATA_FORMAT specifies stride bits [14:17].
> +   * Clear them unless we want a huge stride.
> +   */

Need to use C++ comments: //


> +  if (ST.getGeneration() >= AMDGPUSubtarget::VOLCANIC_ISLANDS)
> +    Rsrc23 &= ~AMDGPU::RSRC_DATA_FORMAT;
> +

Is there a reason why we need to do this only for VI?

-Tom

> +  return Rsrc23;
> +}
> diff --git a/lib/Target/AMDGPU/SIInstrInfo.h b/lib/Target/AMDGPU/SIInstrInfo.h
> index f4b2f2d..ba8b89a 100644
> --- a/lib/Target/AMDGPU/SIInstrInfo.h
> +++ b/lib/Target/AMDGPU/SIInstrInfo.h
> @@ -356,7 +356,7 @@ public:
>    }
>  
>    uint64_t getDefaultRsrcDataFormat() const;
> -
> +  uint64_t getScratchRsrcWords23() const;
>  };
>  
>  namespace AMDGPU {
> diff --git a/lib/Target/AMDGPU/SIPrepareScratchRegs.cpp b/lib/Target/AMDGPU/SIPrepareScratchRegs.cpp
> index f6e57a6..f4a5ac1 100644
> --- a/lib/Target/AMDGPU/SIPrepareScratchRegs.cpp
> +++ b/lib/Target/AMDGPU/SIPrepareScratchRegs.cpp
> @@ -138,8 +138,7 @@ bool SIPrepareScratchRegs::runOnMachineFunction(MachineFunction &MF) {
>        unsigned ScratchRsrcReg =
>            RS.scavengeRegister(&AMDGPU::SReg_128RegClass, 0);
>  
> -      uint64_t Rsrc = AMDGPU::RSRC_DATA_FORMAT | AMDGPU::RSRC_TID_ENABLE |
> -                      0xffffffff; // Size
> +      uint64_t Rsrc23 = TII->getScratchRsrcWords23();
>  
>        unsigned Rsrc0 = TRI->getSubReg(ScratchRsrcReg, AMDGPU::sub0);
>        unsigned Rsrc1 = TRI->getSubReg(ScratchRsrcReg, AMDGPU::sub1);
> @@ -155,11 +154,11 @@ bool SIPrepareScratchRegs::runOnMachineFunction(MachineFunction &MF) {
>                .addReg(ScratchRsrcReg, RegState::ImplicitDefine);
>  
>        BuildMI(MBB, I, DL, TII->get(AMDGPU::S_MOV_B32), Rsrc2)
> -              .addImm(Rsrc & 0xffffffff)
> +              .addImm(Rsrc23 & 0xffffffff)
>                .addReg(ScratchRsrcReg, RegState::ImplicitDefine);
>  
>        BuildMI(MBB, I, DL, TII->get(AMDGPU::S_MOV_B32), Rsrc3)
> -              .addImm(Rsrc >> 32)
> +              .addImm(Rsrc23 >> 32)
>                .addReg(ScratchRsrcReg, RegState::ImplicitDefine);
>  
>        // Scratch Offset
> -- 
> 2.1.4
> 
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