[Mesa-dev] [PATCH v2 1/6] i965/vec4: Only emit one scratch read per instruction for spilled registers

[Iago Toral Quiroga]

---
 src/mesa/drivers/dri/i965/brw_vec4_reg_allocate.cpp | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/brw_vec4_reg_allocate.cpp b/src/mesa/drivers/dri/i965/brw_vec4_reg_allocate.cpp
index cd89edd..a9bf0d8 100644
--- a/src/mesa/drivers/dri/i965/brw_vec4_reg_allocate.cpp
+++ b/src/mesa/drivers/dri/i965/brw_vec4_reg_allocate.cpp
@@ -343,13 +343,17 @@ vec4_visitor::spill_reg(int spill_reg_nr)
 
    /* Generate spill/unspill instructions for the objects being spilled. */
    foreach_block_and_inst(block, vec4_instruction, inst, cfg) {
+      int scratch_reg = -1;
       for (unsigned int i = 0; i < 3; i++) {
          if (inst->src[i].file == GRF && inst->src[i].reg == spill_reg_nr) {
-            src_reg spill_reg = inst->src[i];
-            inst->src[i].reg = alloc.allocate(1);
-            dst_reg temp = dst_reg(inst->src[i]);
-
-            emit_scratch_read(block, inst, temp, spill_reg, spill_offset);
+            if (scratch_reg == -1) {
+               scratch_reg = alloc.allocate(1);
+               src_reg temp = inst->src[i];
+               temp.reg = scratch_reg;
+               emit_scratch_read(block, inst,
+                                 dst_reg(temp), inst->src[i], spill_offset);
+            }
+            inst->src[i].reg = scratch_reg;
          }
       }
 
-- 
1.9.1