[Mesa-dev] [PATCH 3/6] intel/ir: Allow arbitrary scratch flag registers for SHADER_OPCODE_FIND_LIVE_CHANNEL.

[Francisco Jerez]

This shouldn't cause any functional change at this point, it changes
SHADER_OPCODE_FIND_LIVE_CHANNEL to use the flag register specified at
the IR level instead of the hard-coded f1.0, now that it can be
represented in backend_instruction::flag_subreg.  This will be
necessary for scheduling to behave correctly once more things start
making use of f1.0.
---
 src/intel/compiler/brw_eu_emit.c    | 5 +++--
 src/intel/compiler/brw_fs.cpp       | 3 ++-
 src/intel/compiler/brw_fs_builder.h | 2 +-
 3 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/src/intel/compiler/brw_eu_emit.c b/src/intel/compiler/brw_eu_emit.c
index c25d8d6eda0..9fc6d12f288 100644
--- a/src/intel/compiler/brw_eu_emit.c
+++ b/src/intel/compiler/brw_eu_emit.c
@@ -3393,7 +3393,9 @@ brw_find_live_channel(struct brw_codegen *p, struct brw_reg dst,
           */
          inst = brw_FBL(p, vec1(dst), exec_mask);
       } else {
-         const struct brw_reg flag = brw_flag_reg(1, 0);
+         const struct brw_reg flag = brw_flag_reg(
+            brw_inst_flag_reg_nr(devinfo, p->current),
+            brw_inst_flag_subreg_nr(devinfo, p->current));
 
          brw_set_default_exec_size(p, BRW_EXECUTE_1);
          brw_MOV(p, retype(flag, BRW_REGISTER_TYPE_UD), brw_imm_ud(0));
@@ -3412,7 +3414,6 @@ brw_find_live_channel(struct brw_codegen *p, struct brw_reg dst,
             brw_inst_set_mask_control(devinfo, inst, BRW_MASK_ENABLE);
             brw_inst_set_group(devinfo, inst, lower_size * i + 8 * qtr_control);
             brw_inst_set_cond_modifier(devinfo, inst, BRW_CONDITIONAL_Z);
-            brw_inst_set_flag_reg_nr(devinfo, inst, 1);
             brw_inst_set_exec_size(devinfo, inst, cvt(lower_size) - 1);
          }
 
diff --git a/src/intel/compiler/brw_fs.cpp b/src/intel/compiler/brw_fs.cpp
index 6c86b1592fd..0b87d8ab14e 100644
--- a/src/intel/compiler/brw_fs.cpp
+++ b/src/intel/compiler/brw_fs.cpp
@@ -931,7 +931,8 @@ fs_inst::flags_written() const
    if ((conditional_mod && (opcode != BRW_OPCODE_SEL &&
                             opcode != BRW_OPCODE_IF &&
                             opcode != BRW_OPCODE_WHILE)) ||
-       opcode == FS_OPCODE_MOV_DISPATCH_TO_FLAGS) {
+       opcode == FS_OPCODE_MOV_DISPATCH_TO_FLAGS ||
+       opcode == SHADER_OPCODE_FIND_LIVE_CHANNEL) {
       return flag_mask(this);
    } else {
       return flag_mask(dst, size_written);
diff --git a/src/intel/compiler/brw_fs_builder.h b/src/intel/compiler/brw_fs_builder.h
index 87394bc17b3..963588611c6 100644
--- a/src/intel/compiler/brw_fs_builder.h
+++ b/src/intel/compiler/brw_fs_builder.h
@@ -406,7 +406,7 @@ namespace brw {
          const dst_reg chan_index = vgrf(BRW_REGISTER_TYPE_UD);
          const dst_reg dst = vgrf(src.type);
 
-         ubld.emit(SHADER_OPCODE_FIND_LIVE_CHANNEL, chan_index);
+         ubld.emit(SHADER_OPCODE_FIND_LIVE_CHANNEL, chan_index)->flag_subreg = 2;
          ubld.emit(SHADER_OPCODE_BROADCAST, dst, src, component(chan_index, 0));
 
          return src_reg(component(dst, 0));
-- 
2.16.1