[PATCH] R600/SI: Allow partial unrolling and increase thresholds.

[Tom Stellard]

On Wed, Jul 23, 2014 at 07:08:31PM +0000, Matt Arsenault wrote:
> Doubling the base unroll threshold is a conservative increase, and might want to be increased more later.
> 

LGTM.

> http://reviews.llvm.org/D4644
> 
> Files:
>   lib/Target/R600/AMDGPUTargetTransformInfo.cpp
> 
> Index: lib/Target/R600/AMDGPUTargetTransformInfo.cpp
> ===================================================================
> --- lib/Target/R600/AMDGPUTargetTransformInfo.cpp
> +++ lib/Target/R600/AMDGPUTargetTransformInfo.cpp
> @@ -101,6 +101,12 @@
>  
>  void AMDGPUTTI::getUnrollingPreferences(Loop *L,
>                                          UnrollingPreferences &UP) const {
> +  UP.Threshold = 300; // Twice the default.
> +  UP.Count = UINT_MAX;
> +  UP.Partial = true;
> +
> +  // TODO: Do we want runtime unrolling?
> +
>    for (const BasicBlock *BB : L->getBlocks()) {
>      for (const Instruction &I : *BB) {
>        const GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(&I);
> @@ -120,7 +126,7 @@
>          //
>          // Don't use the maximum allowed value here as it will make some
>          // programs way too big.
> -        UP.Threshold = 500;
> +        UP.Threshold = 800;
>        }
>      }
>    }

> Index: lib/Target/R600/AMDGPUTargetTransformInfo.cpp
> ===================================================================
> --- lib/Target/R600/AMDGPUTargetTransformInfo.cpp
> +++ lib/Target/R600/AMDGPUTargetTransformInfo.cpp
> @@ -101,6 +101,12 @@
>  
>  void AMDGPUTTI::getUnrollingPreferences(Loop *L,
>                                          UnrollingPreferences &UP) const {
> +  UP.Threshold = 300; // Twice the default.
> +  UP.Count = UINT_MAX;
> +  UP.Partial = true;
> +
> +  // TODO: Do we want runtime unrolling?
> +
>    for (const BasicBlock *BB : L->getBlocks()) {
>      for (const Instruction &I : *BB) {
>        const GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(&I);
> @@ -120,7 +126,7 @@
>          //
>          // Don't use the maximum allowed value here as it will make some
>          // programs way too big.
> -        UP.Threshold = 500;
> +        UP.Threshold = 800;
>        }
>      }
>    }

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