i965: Set up inputs to the fragment shader according to FP InputsRead.

Sending down data that doesn't get read doesn't make any sense, and
would make handling things like gl_FrontFacing and gl_PointCoord
harder.

1 files changed, 33 insertions, 17 deletions

diff --git a/src/mesa/drivers/dri/i965/brw_wm_glsl.c b/src/mesa/drivers/dri/i965/brw_wm_glsl.c
index a0f299195c4..f60245377e4 100644
--- a/src/mesa/drivers/dri/i965/brw_wm_glsl.c
+++ b/src/mesa/drivers/dri/i965/brw_wm_glsl.c
@@ -347,26 +347,42 @@ static void prealloc_reg(struct brw_wm_compile *c)
         }
     }
 
-    /* fragment shader inputs */
-    for (i = 0; i < VERT_RESULT_MAX; i++) {
-       int fp_input;
-
-       if (i >= VERT_RESULT_VAR0)
-	  fp_input = i - VERT_RESULT_VAR0 + FRAG_ATTRIB_VAR0;
-       else if (i <= VERT_RESULT_TEX7)
-	  fp_input = i;
-       else
-	  fp_input = -1;
-
-       if (fp_input >= 0 && inputs & (1 << fp_input)) {
-	  urb_read_length = reg_index;
+    /* fragment shader inputs: One 2-reg pair of interpolation
+     * coefficients for each vec4 to be set up.
+     */
+    if (intel->gen >= 6) {
+       for (i = 0; i < FRAG_ATTRIB_MAX; i++) {
+	  if (!(c->fp->program.Base.InputsRead & BITFIELD64_BIT(i)))
+	     continue;
+
 	  reg = brw_vec8_grf(reg_index, 0);
-	  for (j = 0; j < 4; j++)
-	     set_reg(c, PROGRAM_PAYLOAD, fp_input, j, reg);
-       }
-       if (c->key.vp_outputs_written & BITFIELD64_BIT(i)) {
+	  for (j = 0; j < 4; j++) {
+	     set_reg(c, PROGRAM_PAYLOAD, i, j, reg);
+	  }
 	  reg_index += 2;
        }
+       urb_read_length = reg_index;
+    } else {
+       for (i = 0; i < VERT_RESULT_MAX; i++) {
+	  int fp_input;
+
+	  if (i >= VERT_RESULT_VAR0)
+	     fp_input = i - VERT_RESULT_VAR0 + FRAG_ATTRIB_VAR0;
+	  else if (i <= VERT_RESULT_TEX7)
+	     fp_input = i;
+	  else
+	     fp_input = -1;
+
+	  if (fp_input >= 0 && inputs & (1 << fp_input)) {
+	     urb_read_length = reg_index;
+	     reg = brw_vec8_grf(reg_index, 0);
+	     for (j = 0; j < 4; j++)
+		set_reg(c, PROGRAM_PAYLOAD, fp_input, j, reg);
+	  }
+	  if (c->key.vp_outputs_written & BITFIELD64_BIT(i)) {
+	     reg_index += 2;
+	  }
+       }
     }
 
     c->prog_data.first_curbe_grf = c->key.nr_payload_regs;