[PATCH] R600: Implement a few simple TTI queries.

[Tom Stellard]

On Fri, Jul 18, 2014 at 07:05:23PM +0000, Matt Arsenault wrote:
> I'm not sure if these have any effect right now.
> 
> http://reviews.llvm.org/D4586
> 
> Files:
>   lib/Target/R600/AMDGPUTargetTransformInfo.cpp
> 
> Index: lib/Target/R600/AMDGPUTargetTransformInfo.cpp
> ===================================================================
> --- lib/Target/R600/AMDGPUTargetTransformInfo.cpp
> +++ lib/Target/R600/AMDGPUTargetTransformInfo.cpp
> @@ -91,6 +91,10 @@
>  
>    PopcntSupportKind getPopcntSupport(unsigned IntTyWidthInBit) const override;
>  
> +  unsigned getNumberOfRegisters(bool Vector) const override;
> +  unsigned getRegisterBitWidth(bool Vector) const override;
> +  unsigned getMaximumUnrollFactor() const override;
> +
>    /// @}
>  };
>  
> @@ -162,3 +166,23 @@
>    assert(isPowerOf2_32(TyWidth) && "Ty width must be power of 2");
>    return ST->hasBCNT(TyWidth) ? PSK_FastHardware : PSK_Software;
>  }
> +
> +unsigned AMDGPUTTI::getNumberOfRegisters(bool Vec) const {
> +  if (Vec)
> +    return 0;
> +
> +  // Number of VGPRs on SI.
> +  if (ST->getGeneration() >= AMDGPUSubtarget::SOUTHERN_ISLANDS)
> +    return 256;
> +
> +  return 4 * 128; // XXX - 4 channels. Should these count as vector instead?
> +}
> +
> +unsigned AMDGPUTTI::getRegisterBitWidth(bool) const {
> +  return 32;
> +}
> +
> +unsigned AMDGPUTTI::getMaximumUnrollFactor() const {
> +  // Semi-arbitrary large amount.
> +  return 64;
> +}

How does this interact with getUnrollingPreference() ?

-Tom