i965/fs: Return more accurate read size for LINTERP from fs_inst::size_read.

The LINTERP virtual instruction only reads three scalar components
from the first 16B of the second source, we can now teach size_read()
about it since its return value is represented with byte granularity.

Reviewed-by: Iago Toral Quiroga <itoral@igalia.com>

diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp
index e18aa72..60907cd 100644 (file)
--- a/src/mesa/drivers/dri/i965/brw_fs.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs.cpp
@@ -848,7 +848,7 @@ fs_inst::size_read(int arg) const
 
    case FS_OPCODE_LINTERP:
       if (arg == 1)
-         return REG_SIZE;
+         return 16;
       break;
 
    case SHADER_OPCODE_LOAD_PAYLOAD: