intel/fs/ra: Stop adding RA interference to too many SENDS nodes

We only have one node per VGRF so this was adding way too much
interference.  No idea how we didn't catch this before.

Shader-db results on Kaby Lake:

    total instructions in shared programs: 15311100 -> 15311100 (0.00%)
    instructions in affected programs: 0 -> 0
    helped: 0
    HURT: 0

    total cycles in shared programs: 355468050 -> 355543197 (0.02%)
    cycles in affected programs: 2472492 -> 2547639 (3.04%)
    helped: 17
    HURT: 20

Fixes: 014edff0d20d "intel/fs: Add interference between SENDS sources"
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>

diff --git a/src/intel/compiler/brw_fs_reg_allocate.cpp b/src/intel/compiler/brw_fs_reg_allocate.cpp
index f8921175f9aab66ab17aafc203d4b322a373e398..35903c4030e77c9132f4e11b2234c830192af701 100644 (file)
--- a/src/intel/compiler/brw_fs_reg_allocate.cpp
+++ b/src/intel/compiler/brw_fs_reg_allocate.cpp
@@ -710,14 +710,9 @@ fs_visitor::assign_regs(bool allow_spilling, bool spill_all)
          if (inst->opcode == SHADER_OPCODE_SEND && inst->ex_mlen > 0 &&
              inst->src[2].file == VGRF &&
              inst->src[3].file == VGRF &&
-             inst->src[2].nr != inst->src[3].nr) {
-            for (unsigned i = 0; i < inst->mlen; i++) {
-               for (unsigned j = 0; j < inst->ex_mlen; j++) {
-                  ra_add_node_interference(g, inst->src[2].nr + i,
-                                           inst->src[3].nr + j);
-               }
-            }
-         }
+             inst->src[2].nr != inst->src[3].nr)
+            ra_add_node_interference(g, inst->src[2].nr,
+                                     inst->src[3].nr);
       }
    }