r600g: Honour destination operand's writemask in the SCS implementation.

If we are not going to write to the X or Y components of the destination
vector we also don't need to prepare to compute SIN or COS.

Signed-off-by: Tilman Sauerbeck <tilman@code-monkey.de>

diff --git a/src/gallium/drivers/r600/r600_shader.c b/src/gallium/drivers/r600/r600_shader.c
index bce52973136f41fd2808a5b81341d5d9ea199eb0..523b6d24515610e217b846a44d69eeddbac35c45 100644 (file)
--- a/src/gallium/drivers/r600/r600_shader.c
+++ b/src/gallium/drivers/r600/r600_shader.c
@@ -926,38 +926,47 @@ static int tgsi_scs(struct r600_shader_ctx *ctx)
        struct r600_bc_alu alu;
        int r;
 
-       r = tgsi_setup_trig(ctx, r600_src);
-       if (r)
-               return r;
-
+       /* We'll only need the trig stuff if we are going to write to the
+        * X or Y components of the destination vector.
+        */
+       if (likely(inst->Dst[0].Register.WriteMask & TGSI_WRITEMASK_XY)) {
+               r = tgsi_setup_trig(ctx, r600_src);
+               if (r)
+                       return r;
+       }
 
        /* dst.x = COS */
-       memset(&alu, 0, sizeof(struct r600_bc_alu));
-       alu.inst = CTX_INST(V_SQ_ALU_WORD1_OP2_SQ_OP2_INST_COS);
-       r = tgsi_dst(ctx, &inst->Dst[0], 0, &alu.dst);
-       if (r)
-               return r;
+       if (inst->Dst[0].Register.WriteMask & TGSI_WRITEMASK_X) {
+               memset(&alu, 0, sizeof(struct r600_bc_alu));
+               alu.inst = CTX_INST(V_SQ_ALU_WORD1_OP2_SQ_OP2_INST_COS);
+               r = tgsi_dst(ctx, &inst->Dst[0], 0, &alu.dst);
+               if (r)
+                       return r;
 
-       alu.src[0].sel = ctx->temp_reg;
-       alu.src[0].chan = 0;
-       alu.last = 1;
-       r = r600_bc_add_alu(ctx->bc, &alu);
-       if (r)
-               return r;
+               alu.src[0].sel = ctx->temp_reg;
+               alu.src[0].chan = 0;
+               alu.last = 1;
+               r = r600_bc_add_alu(ctx->bc, &alu);
+               if (r)
+                       return r;
+       }
 
        /* dst.y = SIN */
-       memset(&alu, 0, sizeof(struct r600_bc_alu));
-       alu.inst = CTX_INST(V_SQ_ALU_WORD1_OP2_SQ_OP2_INST_SIN);
-       r = tgsi_dst(ctx, &inst->Dst[0], 1, &alu.dst);
-       if (r)
-               return r;
+       if (inst->Dst[0].Register.WriteMask & TGSI_WRITEMASK_Y) {
+               memset(&alu, 0, sizeof(struct r600_bc_alu));
+               alu.inst = CTX_INST(V_SQ_ALU_WORD1_OP2_SQ_OP2_INST_SIN);
+               r = tgsi_dst(ctx, &inst->Dst[0], 1, &alu.dst);
+               if (r)
+                       return r;
+
+               alu.src[0].sel = ctx->temp_reg;
+               alu.src[0].chan = 0;
+               alu.last = 1;
+               r = r600_bc_add_alu(ctx->bc, &alu);
+               if (r)
+                       return r;
+       }
 
-       alu.src[0].sel = ctx->temp_reg;
-       alu.src[0].chan = 0;
-       alu.last = 1;
-       r = r600_bc_add_alu(ctx->bc, &alu);
-       if (r)
-               return r;
        return 0;
 }