r600g: mask unused source components for SAMPLE

This results in more clean shader code and may improve the quality of
optimized code produced by r600-sb due to eliminated false dependencies
in some cases.

Signed-off-by: Vadim Girlin <vadimgirlin@gmail.com>

diff --git a/src/gallium/drivers/r600/r600_shader.c b/src/gallium/drivers/r600/r600_shader.c
index bb54e38..f0d3be4 100644 (file)
--- a/src/gallium/drivers/r600/r600_shader.c
+++ b/src/gallium/drivers/r600/r600_shader.c
@@ -4743,6 +4743,26 @@ static int tgsi_tex(struct r600_shader_ctx *ctx)
                /* the array index is read from Z */
                tex.coord_type_z = 0;
 
+       /* mask unused source components */
+       if (opcode == FETCH_OP_SAMPLE) {
+               switch (inst->Texture.Texture) {
+               case TGSI_TEXTURE_2D:
+               case TGSI_TEXTURE_RECT:
+                       tex.src_sel_z = 7;
+                       tex.src_sel_w = 7;
+                       break;
+               case TGSI_TEXTURE_1D_ARRAY:
+                       tex.src_sel_y = 7;
+                       tex.src_sel_w = 7;
+                       break;
+               case TGSI_TEXTURE_1D:
+                       tex.src_sel_y = 7;
+                       tex.src_sel_z = 7;
+                       tex.src_sel_w = 7;
+                       break;
+               }
+       }
+
        r = r600_bytecode_add_tex(ctx->bc, &tex);
        if (r)
                return r;