llvmpipe: Per quad interpolation.

First interpolate the 4 quads upper left corners, then sub-interpolate
each quad pixel. Do the perspective divide once per quad.

Saves some muls and reciprocates. But doesn't seem to make a
noticeable improvement.

It make the code simpler and more compact, so commiting anyway.

1 files changed, 4 insertions, 5 deletions

diff --git a/src/gallium/drivers/llvmpipe/lp_bld_interp.h b/src/gallium/drivers/llvmpipe/lp_bld_interp.h
index 45a430701f..2905513301 100644
--- a/src/gallium/drivers/llvmpipe/lp_bld_interp.h
+++ b/src/gallium/drivers/llvmpipe/lp_bld_interp.h
@@ -58,12 +58,11 @@ struct lp_build_interp_soa_context
    unsigned mask[1 + PIPE_MAX_SHADER_INPUTS]; /**< TGSI_WRITE_MASK_x */
    enum lp_interp interp[1 + PIPE_MAX_SHADER_INPUTS];
 
-   LLVMValueRef a0  [1 + PIPE_MAX_SHADER_INPUTS][NUM_CHANNELS];
-   LLVMValueRef dadx[1 + PIPE_MAX_SHADER_INPUTS][NUM_CHANNELS];
-   LLVMValueRef dady[1 + PIPE_MAX_SHADER_INPUTS][NUM_CHANNELS];
+   LLVMValueRef x;
+   LLVMValueRef y;
 
-   /* Attribute values before perspective divide */
-   LLVMValueRef attribs_pre[1 + PIPE_MAX_SHADER_INPUTS][NUM_CHANNELS];
+   LLVMValueRef a   [1 + PIPE_MAX_SHADER_INPUTS][NUM_CHANNELS];
+   LLVMValueRef dadq[1 + PIPE_MAX_SHADER_INPUTS][NUM_CHANNELS];
 
    LLVMValueRef attribs[1 + PIPE_MAX_SHADER_INPUTS][NUM_CHANNELS];