Mesa (master): i965/fs: Track liveness of the flag register.

[Matt Turner]

Module: Mesa
Branch: master
Commit: bf8deb55146696b2332d9ea29f6242d236e1b46a
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=bf8deb55146696b2332d9ea29f6242d236e1b46a

Author: Matt Turner <mattst88 at gmail.com>
Date:   Tue Oct 28 19:53:53 2014 -0700

i965/fs: Track liveness of the flag register.

Reviewed-by: Kenneth Graunke <kenneth at whitecape.org>

---

 .../drivers/dri/i965/brw_fs_live_variables.cpp     |   36 ++++++++++++++++++++
 src/mesa/drivers/dri/i965/brw_fs_live_variables.h  |    5 +++
 2 files changed, 41 insertions(+)

diff --git a/src/mesa/drivers/dri/i965/brw_fs_live_variables.cpp b/src/mesa/drivers/dri/i965/brw_fs_live_variables.cpp
index ab81e94..2512b79 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_live_variables.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_live_variables.cpp
@@ -157,6 +157,19 @@ fs_live_variables::setup_def_use()
                reg.reg_offset++;
             }
 	 }
+         if (inst->reads_flag()) {
+            /* The vertical combination predicates read f0.0 and f0.1. */
+            if (inst->predicate == BRW_PREDICATE_ALIGN1_ANYV ||
+                inst->predicate == BRW_PREDICATE_ALIGN1_ALLV) {
+               assert(inst->flag_subreg == 0);
+               if (!BITSET_TEST(bd->flag_def, 1)) {
+                  BITSET_SET(bd->flag_use, 1);
+               }
+            }
+            if (!BITSET_TEST(bd->flag_def, inst->flag_subreg)) {
+               BITSET_SET(bd->flag_use, inst->flag_subreg);
+            }
+         }
 
          /* Set def[] for this instruction */
          if (inst->dst.file == GRF) {
@@ -166,6 +179,11 @@ fs_live_variables::setup_def_use()
                reg.reg_offset++;
             }
 	 }
+         if (inst->writes_flag()) {
+            if (!BITSET_TEST(bd->flag_use, inst->flag_subreg)) {
+               BITSET_SET(bd->flag_def, inst->flag_subreg);
+            }
+         }
 
 	 ip++;
       }
@@ -199,6 +217,13 @@ fs_live_variables::compute_live_variables()
                cont = true;
 	    }
 	 }
+         BITSET_WORD new_livein = (bd->flag_use[0] |
+                                   (bd->flag_liveout[0] &
+                                    ~bd->flag_def[0]));
+         if (new_livein & ~bd->flag_livein[0]) {
+            bd->flag_livein[0] |= new_livein;
+            cont = true;
+         }
 
 	 /* Update liveout */
 	 foreach_list_typed(bblock_link, child_link, link, &block->children) {
@@ -212,6 +237,12 @@ fs_live_variables::compute_live_variables()
                   cont = true;
                }
 	    }
+            BITSET_WORD new_liveout = (child_bd->flag_livein[0] &
+                                       ~bd->flag_liveout[0]);
+            if (new_liveout) {
+               bd->flag_liveout[0] |= new_liveout;
+               cont = true;
+            }
 	 }
       }
    }
@@ -283,6 +314,11 @@ fs_live_variables::fs_live_variables(fs_visitor *v, const cfg_t *cfg)
       block_data[i].use = rzalloc_array(mem_ctx, BITSET_WORD, bitset_words);
       block_data[i].livein = rzalloc_array(mem_ctx, BITSET_WORD, bitset_words);
       block_data[i].liveout = rzalloc_array(mem_ctx, BITSET_WORD, bitset_words);
+
+      block_data[i].flag_def[0] = 0;
+      block_data[i].flag_use[0] = 0;
+      block_data[i].flag_livein[0] = 0;
+      block_data[i].flag_liveout[0] = 0;
    }
 
    setup_def_use();
diff --git a/src/mesa/drivers/dri/i965/brw_fs_live_variables.h b/src/mesa/drivers/dri/i965/brw_fs_live_variables.h
index 5d63901..2bfb583 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_live_variables.h
+++ b/src/mesa/drivers/dri/i965/brw_fs_live_variables.h
@@ -51,6 +51,11 @@ struct block_data {
 
    /** Which defs reach the exit point of the block. */
    BITSET_WORD *liveout;
+
+   BITSET_WORD flag_def[1];
+   BITSET_WORD flag_use[1];
+   BITSET_WORD flag_livein[1];
+   BITSET_WORD flag_liveout[1];
 };
 
 class fs_live_variables {