[PATCH] R600/SI: Insert s_waitcnt before s_barrier instructions.

[Tom Stellard]

Ping.

On Mon, Dec 29, 2014 at 03:14:25PM -0500, Tom Stellard wrote:
> This ensures that all memory operations are complete when all threads
> reach the barrier.
> ---
>  lib/Target/R600/SIInsertWaits.cpp               | 6 +++++-
>  test/CodeGen/R600/llvm.AMDGPU.barrier.global.ll | 4 +++-
>  test/CodeGen/R600/llvm.AMDGPU.barrier.local.ll  | 5 ++++-
>  3 files changed, 12 insertions(+), 3 deletions(-)
> 
> diff --git a/lib/Target/R600/SIInsertWaits.cpp b/lib/Target/R600/SIInsertWaits.cpp
> index 2e56508..181b116 100644
> --- a/lib/Target/R600/SIInsertWaits.cpp
> +++ b/lib/Target/R600/SIInsertWaits.cpp
> @@ -428,7 +428,11 @@ bool SIInsertWaits::runOnMachineFunction(MachineFunction &MF) {
>      for (MachineBasicBlock::iterator I = MBB.begin(), E = MBB.end();
>           I != E; ++I) {
>  
> -      Changes |= insertWait(MBB, I, handleOperands(*I));
> +      // Wait for everything before a barrier.
> +      if (I->getOpcode() == AMDGPU::S_BARRIER)
> +        Changes |= insertWait(MBB, I, LastIssued);
> +      else
> +        Changes |= insertWait(MBB, I, handleOperands(*I));
>        pushInstruction(MBB, I);
>      }
>  
> diff --git a/test/CodeGen/R600/llvm.AMDGPU.barrier.global.ll b/test/CodeGen/R600/llvm.AMDGPU.barrier.global.ll
> index 98f6695..b20457e 100644
> --- a/test/CodeGen/R600/llvm.AMDGPU.barrier.global.ll
> +++ b/test/CodeGen/R600/llvm.AMDGPU.barrier.global.ll
> @@ -3,7 +3,9 @@
>  
>  ; FUNC-LABEL: {{^}}test_barrier_global:
>  ; EG: GROUP_BARRIER
> -; SI: s_barrier
> +; SI: buffer_store_dword
> +; SI: s_waitcnt
> +; SI-NEXT: s_barrier
>  
>  define void @test_barrier_global(i32 addrspace(1)* %out) {
>  entry:
> diff --git a/test/CodeGen/R600/llvm.AMDGPU.barrier.local.ll b/test/CodeGen/R600/llvm.AMDGPU.barrier.local.ll
> index 92fe9f2..ca3c8b8 100644
> --- a/test/CodeGen/R600/llvm.AMDGPU.barrier.local.ll
> +++ b/test/CodeGen/R600/llvm.AMDGPU.barrier.local.ll
> @@ -3,7 +3,10 @@
>  
>  ; FUNC-LABEL: {{^}}test_barrier_local:
>  ; EG: GROUP_BARRIER
> -; SI: s_barrier
> +
> +; SI: buffer_store_dword
> +; SI: s_waitcnt
> +; SI-NEXT: s_barrier
>  
>  define void @test_barrier_local(i32 addrspace(1)* %out) {
>  entry:
> -- 
> 1.8.5.5
> 
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