r600_shader: only load from LDS what is really used

Use the destination write mask to determine which values are really to be
read from LDS and load only these.

Reviewed-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Gert Wollny <gw.fossdev@gmail.com>

diff --git a/src/gallium/drivers/r600/r600_shader.c b/src/gallium/drivers/r600/r600_shader.c
index 9345291cef86199156a14aab6859584f3345ea23..2f2e002115a557eb07b6b4d20dc59062d81b02d6 100644 (file)
--- a/src/gallium/drivers/r600/r600_shader.c
+++ b/src/gallium/drivers/r600/r600_shader.c
@@ -379,7 +379,7 @@ static void r600_bytecode_src(struct r600_bytecode_alu_src *bc_src,
                        const struct r600_shader_src *shader_src,
                        unsigned chan);
 static int do_lds_fetch_values(struct r600_shader_ctx *ctx, unsigned temp_reg,
-                              unsigned dst_reg);
+                              unsigned dst_reg, unsigned mask);
 
 static int tgsi_last_instruction(unsigned writemask)
 {
@@ -1026,7 +1026,7 @@ static int tgsi_declaration(struct r600_shader_ctx *ctx)
                        if (r)
                                return r;
 
-                       do_lds_fetch_values(ctx, temp_reg, dreg);
+                       do_lds_fetch_values(ctx, temp_reg, dreg, 0xf);
                }
                else if (d->Semantic.Name == TGSI_SEMANTIC_TESSCOORD) {
                        /* MOV r1.x, r0.x;
@@ -1744,14 +1744,18 @@ static int r600_get_byte_address(struct r600_shader_ctx *ctx, int temp_reg,
 }
 
 static int do_lds_fetch_values(struct r600_shader_ctx *ctx, unsigned temp_reg,
-                              unsigned dst_reg)
+                              unsigned dst_reg, unsigned mask)
 {
        struct r600_bytecode_alu alu;
        int r, i;
 
        if ((ctx->bc->cf_last->ndw>>1) >= 0x60)
                ctx->bc->force_add_cf = 1;
+
        for (i = 1; i < 4; i++) {
+               if (!(mask & (1 << i)))
+                       continue;
+
                r = single_alu_op2(ctx, ALU_OP2_ADD_INT,
                                   temp_reg, i,
                                   temp_reg, 0,
@@ -1760,6 +1764,9 @@ static int do_lds_fetch_values(struct r600_shader_ctx *ctx, unsigned temp_reg,
                        return r;
        }
        for (i = 0; i < 4; i++) {
+               if (! (mask & (1 << i)))
+                       continue;
+
                /* emit an LDS_READ_RET */
                memset(&alu, 0, sizeof(alu));
                alu.op = LDS_OP1_LDS_READ_RET;
@@ -1775,6 +1782,8 @@ static int do_lds_fetch_values(struct r600_shader_ctx *ctx, unsigned temp_reg,
                        return r;
        }
        for (i = 0; i < 4; i++) {
+               if (! (mask & (1 << i)))
+                       continue;
                /* then read from LDS_OQ_A_POP */
                memset(&alu, 0, sizeof(alu));
 
@@ -1792,6 +1801,16 @@ static int do_lds_fetch_values(struct r600_shader_ctx *ctx, unsigned temp_reg,
        return 0;
 }
 
+static int fetch_mask(struct tgsi_src_register *reg)
+{
+       int mask = 0;
+       mask |= 1 << reg->SwizzleX;
+       mask |= 1 << reg->SwizzleY;
+       mask |= 1 << reg->SwizzleZ;
+       mask |= 1 << reg->SwizzleW;
+       return mask;
+}
+
 static int fetch_tes_input(struct r600_shader_ctx *ctx, struct tgsi_full_src_register *src, unsigned int dst_reg)
 {
        int r;
@@ -1808,7 +1827,7 @@ static int fetch_tes_input(struct r600_shader_ctx *ctx, struct tgsi_full_src_reg
        if (r)
                return r;
 
-       r = do_lds_fetch_values(ctx, temp_reg, dst_reg);
+       r = do_lds_fetch_values(ctx, temp_reg, dst_reg, fetch_mask(&src->Register));
        if (r)
                return r;
        return 0;
@@ -1834,7 +1853,7 @@ static int fetch_tcs_input(struct r600_shader_ctx *ctx, struct tgsi_full_src_reg
        if (r)
                return r;
 
-       r = do_lds_fetch_values(ctx, temp_reg, dst_reg);
+       r = do_lds_fetch_values(ctx, temp_reg, dst_reg, fetch_mask(&src->Register));
        if (r)
                return r;
        return 0;
@@ -1856,7 +1875,7 @@ static int fetch_tcs_output(struct r600_shader_ctx *ctx, struct tgsi_full_src_re
        if (r)
                return r;
 
-       r = do_lds_fetch_values(ctx, temp_reg, dst_reg);
+       r = do_lds_fetch_values(ctx, temp_reg, dst_reg, fetch_mask(&src->Register));
        if (r)
                return r;
        return 0;
@@ -2795,7 +2814,7 @@ static int r600_tess_factor_read(struct r600_shader_ctx *ctx,
        if (r)
                return r;
 
-       do_lds_fetch_values(ctx, temp_reg, dreg);
+       do_lds_fetch_values(ctx, temp_reg, dreg, 0xf);
        return 0;
 }