[Mesa-dev] [PATCH] AMDGPU: Update SI flow control comments to match current code.

[Tom Stellard]

On Thu, Nov 01, 2012 at 10:30:19AM +0100, Michel Dänzer wrote:
> From: Michel Dänzer <michel.daenzer at amd.com>
> 
> 
> Signed-off-by: Michel Dänzer <michel.daenzer at amd.com>

Reviewed-by: Tom Stellard <thomas.stellard at amd.com>

> ---
>  lib/Target/AMDGPU/SILowerFlowControl.cpp |    9 +++++----
>  1 file changed, 5 insertions(+), 4 deletions(-)
> 
> diff --git a/lib/Target/AMDGPU/SILowerFlowControl.cpp b/lib/Target/AMDGPU/SILowerFlowControl.cpp
> index b901688..0d90c13 100644
> --- a/lib/Target/AMDGPU/SILowerFlowControl.cpp
> +++ b/lib/Target/AMDGPU/SILowerFlowControl.cpp
> @@ -31,6 +31,7 @@
>  //
>  // %SGPR0 = S_MOV_B64 %EXEC          // Save the current exec mask
>  // %EXEC = S_AND_B64 %VCC, %EXEC     // Update the exec mask
> +// %SGPR0 = S_XOR_B64 %SGPR0, %EXEC  // Clear live bits from saved exec mask
>  // S_CBRANCH_EXECZ label0            // This instruction is an
>  //                                   // optimization which allows us to
>  //                                   // branch if all the bits of
> @@ -38,14 +39,14 @@
>  // %VGPR0 = V_ADD_F32 %VGPR0, %VGPR0 // Do the IF block of the branch
>  //
>  // label0:
> -// %EXEC = S_NOT_B64 %EXEC            // Invert the exec mask for the
> -//                                    // Then block.
> -// %EXEC = S_AND_B64 %SGPR0, %EXEC
> +// %SGPR2 = S_MOV_B64 %EXEC           // Save the current exec mask
> +// %EXEC = S_MOV_B64 %SGPR0           // Restore the exec mask for the Then block
> +// %SGPR0 = S_MOV_B64 %SGPR2          // Save the exec mask from the If block
>  // S_BRANCH_EXECZ label1              // Use our branch optimization
>  //                                    // instruction again.
>  // %VGPR0 = V_SUB_F32 %VGPR0, %VGPR   // Do the THEN block
>  // label1:
> -// S_MOV_B64                          // Restore the old EXEC value
> +// %EXEC = S_OR_B64 %EXEC, %SGPR0     // Re-enable saved exec mask bits
>  //===----------------------------------------------------------------------===//
>  
>  #include "AMDGPU.h"
> -- 
> 1.7.10.4
> 
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