[Mesa-dev] [PATCH 05/15] i965/fs: Stop relying on param_size in assign_constant_locations

[Jason Ekstrand]

Now that we have MOV_INDIRECT opcodes, we have all of the size information
we need directly in the opcode.  With a little restructuring of the
algorithm used in assign_constant_locations we don't need param_size
anymore.  The big thing to watch out for now, however, is that you can have
two ranges overlap where neither contains the other.  In order to deal with
this, we make the first pass just flag what needs pulling and handle
assigning pull constant locations until later.
---
 src/mesa/drivers/dri/i965/brw_fs.cpp | 44 ++++++++++++++----------------------
 1 file changed, 17 insertions(+), 27 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp
index 786c5fb..1add656 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs.cpp
@@ -1920,14 +1920,12 @@ fs_visitor::assign_constant_locations()
    if (dispatch_width != 8)
       return;
 
-   unsigned int num_pull_constants = 0;
-
-   pull_constant_loc = ralloc_array(mem_ctx, int, uniforms);
-   memset(pull_constant_loc, -1, sizeof(pull_constant_loc[0]) * uniforms);
-
    bool is_live[uniforms];
    memset(is_live, 0, sizeof(is_live));
 
+   bool needs_pull[uniforms];
+   memset(needs_pull, 0, sizeof(is_live));
+
    /* First, we walk through the instructions and do two things:
     *
     *  1) Figure out which uniforms are live.
@@ -1943,20 +1941,15 @@ fs_visitor::assign_constant_locations()
          if (inst->src[i].file != UNIFORM)
             continue;
 
-         if (inst->opcode == SHADER_OPCODE_MOV_INDIRECT && i == 0) {
-            int uniform = inst->src[0].nr;
+         int constant_nr = inst->src[i].nr + inst->src[i].reg_offset;
 
-            /* If this array isn't already present in the pull constant buffer,
-             * add it.
-             */
-            if (pull_constant_loc[uniform] == -1) {
-               assert(param_size[uniform]);
-               for (int j = 0; j < param_size[uniform]; j++)
-                  pull_constant_loc[uniform + j] = num_pull_constants++;
+         if (inst->opcode == SHADER_OPCODE_MOV_INDIRECT && i == 0) {
+            for (unsigned j = 0; j < inst->src[2].ud / 4; j++) {
+               is_live[constant_nr + j] = true;
+               needs_pull[constant_nr + j] = true;
             }
          } else {
             /* Mark the the one accessed uniform as live */
-            int constant_nr = inst->src[i].nr + inst->src[i].reg_offset;
             if (constant_nr >= 0 && constant_nr < (int) uniforms)
                is_live[constant_nr] = true;
          }
@@ -1973,26 +1966,23 @@ fs_visitor::assign_constant_locations()
     */
    unsigned int max_push_components = 16 * 8;
    unsigned int num_push_constants = 0;
+   unsigned int num_pull_constants = 0;
 
    push_constant_loc = ralloc_array(mem_ctx, int, uniforms);
+   pull_constant_loc = ralloc_array(mem_ctx, int, uniforms);
 
    for (unsigned int i = 0; i < uniforms; i++) {
-      if (!is_live[i] || pull_constant_loc[i] != -1) {
-         /* This UNIFORM register is either dead, or has already been demoted
-          * to a pull const.  Mark it as no longer living in the param[] array.
-          */
-         push_constant_loc[i] = -1;
+      push_constant_loc[i] = -1;
+      pull_constant_loc[i] = -1;
+
+      if (!is_live[i])
          continue;
-      }
 
-      if (num_push_constants < max_push_components) {
-         /* Retain as a push constant.  Record the location in the params[]
-          * array.
-          */
+      if (!needs_pull[i] && num_push_constants < max_push_components) {
+         /* Retain as a push constant */
          push_constant_loc[i] = num_push_constants++;
       } else {
-         /* Demote to a pull constant. */
-         push_constant_loc[i] = -1;
+         /* We have to pull it */
          pull_constant_loc[i] = num_pull_constants++;
       }
    }
-- 
2.5.0.400.gff86faf