[llvm] r276438 - AMDGPU: Fix groupstaticsize for large LDS

[Matt Arsenault via llvm-commits]

Hi, this should go to the release branch

-Matt

On 07/22/2016 10:01 AM, Matt Arsenault via llvm-commits wrote:
> Author: arsenm
> Date: Fri Jul 22 12:01:33 2016
> New Revision: 276438
>
> URL: http://llvm.org/viewvc/llvm-project?rev=276438&view=rev
> Log:
> AMDGPU: Fix groupstaticsize for large LDS
>
> The size can exceed s_movk_i32's limit, and we don't
> want to use it this early since it inhibits optimizations.
>
> This should probably be merged to the release branch.
>
> Modified:
>      llvm/trunk/lib/Target/AMDGPU/SIISelLowering.cpp
>      llvm/trunk/test/CodeGen/AMDGPU/llvm.amdgcn.groupstaticsize.ll
>
> Modified: llvm/trunk/lib/Target/AMDGPU/SIISelLowering.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/AMDGPU/SIISelLowering.cpp?rev=276438&r1=276437&r2=276438&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Target/AMDGPU/SIISelLowering.cpp (original)
> +++ llvm/trunk/lib/Target/AMDGPU/SIISelLowering.cpp Fri Jul 22 12:01:33 2016
> @@ -1433,9 +1433,9 @@ MachineBasicBlock *SITargetLowering::Emi
>       MachineFunction *MF = BB->getParent();
>       SIMachineFunctionInfo *MFI = MF->getInfo<SIMachineFunctionInfo>();
>       DebugLoc DL = MI.getDebugLoc();
> -    BuildMI(*BB, MI, DL, TII->get(AMDGPU::S_MOVK_I32))
> -        .addOperand(MI.getOperand(0))
> -        .addImm(MFI->LDSSize);
> +    BuildMI(*BB, MI, DL, TII->get(AMDGPU::S_MOV_B32))
> +      .addOperand(MI.getOperand(0))
> +      .addImm(MFI->LDSSize);
>       MI.eraseFromParent();
>       return BB;
>     }
>
> Modified: llvm/trunk/test/CodeGen/AMDGPU/llvm.amdgcn.groupstaticsize.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/AMDGPU/llvm.amdgcn.groupstaticsize.ll?rev=276438&r1=276437&r2=276438&view=diff
> ==============================================================================
> --- llvm/trunk/test/CodeGen/AMDGPU/llvm.amdgcn.groupstaticsize.ll (original)
> +++ llvm/trunk/test/CodeGen/AMDGPU/llvm.amdgcn.groupstaticsize.ll Fri Jul 22 12:01:33 2016
> @@ -5,8 +5,10 @@
>   @lds0 = addrspace(3) global [512 x float] undef, align 4
>   @lds1 = addrspace(3) global [256 x float] undef, align 4
>   
> + at large = addrspace(3) global [4096 x i32] undef, align 4
> +
>   ; CHECK-LABEL: {{^}}groupstaticsize_test0:
> -; CHECK: s_movk_i32 s{{[0-9]+}}, 0x800
> +; CHECK: v_mov_b32_e32 v{{[0-9]+}}, 0x800{{$}}
>   define void @groupstaticsize_test0(float addrspace(1)* %out, i32 addrspace(1)* %lds_size) #0 {
>     %tid.x = tail call i32 @llvm.amdgcn.workitem.id.x() #1
>     %idx.0 = add nsw i32 %tid.x, 64
> @@ -20,7 +22,7 @@ define void @groupstaticsize_test0(float
>   }
>   
>   ; CHECK-LABEL: {{^}}groupstaticsize_test1:
> -; CHECK: s_movk_i32 s{{[0-9]+}}, 0xc00
> +; CHECK: v_mov_b32_e32 v{{[0-9]+}}, 0xc00{{$}}
>   define void @groupstaticsize_test1(float addrspace(1)* %out, i32 %cond, i32 addrspace(1)* %lds_size) {
>   entry:
>     %static_lds_size = call i32 @llvm.amdgcn.groupstaticsize() #1
> @@ -46,6 +48,17 @@ endif:
>     ret void
>   }
>   
> +; Exceeds 16-bit simm limit of s_movk_i32
> +; CHECK-LABEL: {{^}}large_groupstaticsize:
> +; CHECK: v_mov_b32_e32 [[REG:v[0-9]+]], 0x4000{{$}}
> +define void @large_groupstaticsize(i32 addrspace(1)* %size, i32 %idx) #0 {
> +  %gep = getelementptr inbounds [4096 x i32], [4096 x i32] addrspace(3)* @large, i32 0, i32 %idx
> +  store volatile i32 0, i32 addrspace(3)* %gep
> +  %static_lds_size = call i32 @llvm.amdgcn.groupstaticsize()
> +  store i32 %static_lds_size, i32 addrspace(1)* %size
> +  ret void
> +}
> +
>   declare i32 @llvm.amdgcn.groupstaticsize() #1
>   declare i32 @llvm.amdgcn.workitem.id.x() #1
>   
>
>
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