From: Francisco Jerez <currojerez@riseup.net>
Date: Sat, 30 Apr 2016 02:47:44 +0000 (-0700)
Subject: i965/fs: Pass a BAD_FILE register to the logical FB write when oMask is unused.
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=b0c8e5e0c88f7c5d7395715e58a8731e2ab55f7e;p=mesa.git

i965/fs: Pass a BAD_FILE register to the logical FB write when oMask is unused.

This will let the optimizer know that the sample mask value is unused
so its definition can be DCE'ed.

Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
---

diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp
index f5add6ec676..0b350d5ff76 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs.cpp
@@ -3797,7 +3797,7 @@ lower_fb_write_logical_send(const fs_builder &bld, fs_inst *inst,
       length++;
    }
 
-   if (prog_data->uses_omask) {
+   if (sample_mask.file != BAD_FILE) {
       sources[length] = fs_reg(VGRF, bld.shader->alloc.allocate(1),
                                BRW_REGISTER_TYPE_UD);
 
diff --git a/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp b/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
index 25e1a445136..3a49794c9cf 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
@@ -394,7 +394,8 @@ fs_visitor::emit_single_fb_write(const fs_builder &bld,
 
    const fs_reg sources[] = {
       color0, color1, src0_alpha, src_depth, dst_depth, src_stencil,
-      sample_mask, brw_imm_ud(components)
+      (prog_data->uses_omask ? sample_mask : fs_reg()),
+      brw_imm_ud(components)
    };
    assert(ARRAY_SIZE(sources) - 1 == FB_WRITE_LOGICAL_SRC_COMPONENTS);
    fs_inst *write = bld.emit(FS_OPCODE_FB_WRITE_LOGICAL, fs_reg(),