Mesa (master): i965: Fix Haswell discard regressions since Gen4-5 line AA fix.

[Kenneth Graunke]

Module: Mesa
Branch: master
Commit: a2ad771671d94feae16b35c26ed4d1907f74f50e
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=a2ad771671d94feae16b35c26ed4d1907f74f50e

Author: Kenneth Graunke <kenneth at whitecape.org>
Date:   Tue Jun 10 18:50:03 2014 -0700

i965: Fix Haswell discard regressions since Gen4-5 line AA fix.

In commit dc2d3a7f5c217a7cee92380fbf503924a9591bea, Iago accidentally
moved fire_fb_write() above the brw_pop_insn_state(), which caused the
SEND to lose its predication and change from WE_normal to WE_all.
Haswell uses predicated SENDs for discards, so this broke Piglit's
tests for discards.

We want the Gen4-5 MOV to be uncompressed, unpredicated, and unmasked,
but the actual FB write itself should respect those.  So, pop state
first, and force it again around the single MOV.

Signed-off-by: Kenneth Graunke <kenneth at whitecape.org>
Reviewed-by: Matt Turner <mattst88 at gmail.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=79903

---

 src/mesa/drivers/dri/i965/brw_fs_generator.cpp |    9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/brw_fs_generator.cpp b/src/mesa/drivers/dri/i965/brw_fs_generator.cpp
index 3787d24..d21b4e2 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_generator.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_generator.cpp
@@ -106,9 +106,14 @@ fs_generator::fire_fb_write(fs_inst *inst,
    uint32_t msg_control;
 
    if (brw->gen < 6) {
+      brw_push_insn_state(p);
+      brw_set_default_mask_control(p, BRW_MASK_DISABLE);
+      brw_set_default_predicate_control(p, BRW_PREDICATE_NONE);
+      brw_set_default_compression_control(p, BRW_COMPRESSION_NONE);
       brw_MOV(p,
               brw_message_reg(base_reg + 1),
               brw_vec8_grf(1, 0));
+      brw_pop_insn_state(p);
    }
 
    if (this->dual_source_output)
@@ -196,6 +201,8 @@ fs_generator::generate_fb_write(fs_inst *inst)
       implied_header = brw_null_reg();
    }
 
+   brw_pop_insn_state(p);
+
    if (!runtime_check_aads_emit) {
       fire_fb_write(inst, inst->base_mrf, implied_header, inst->mlen);
    } else {
@@ -221,8 +228,6 @@ fs_generator::generate_fb_write(fs_inst *inst)
       brw_land_fwd_jump(p, jmp);
       fire_fb_write(inst, inst->base_mrf, implied_header, inst->mlen);
    }
-
-   brw_pop_insn_state(p);
 }
 
 void