i965: Fix undefined df bits in brw_reg comparisons.

Commit 5310bca024f77da40ea6f4c275455f9cb0528f9e added a new "double df"
field to the brw_reg struct, adding an extra 4 bytes of data that isn't
usually initialized (or may contain irrelevant garbage if the struct is
mutated).  This means that it's no longer safe to memcmp().

Instead, add a brw_regs_equal() function which ignores the extra df bits
unless they matter.  To keep the implementation cheap, we wrap the first
set of fields in a union/struct so that we can use a single DWord
comparison.

v2: Drop unnecessary casts (caught by Francisco Jerez).

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Francisco Jerez <currojerez@riseup.net>
Reviewed-by: Samuel Iglesias Gonsálvez <siglesias@igalia.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/src/mesa/drivers/dri/i965/brw_fs_generator.cpp b/src/mesa/drivers/dri/i965/brw_fs_generator.cpp
index 4f6f3a3..3b50a82 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_generator.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_generator.cpp
@@ -1010,7 +1010,7 @@ fs_generator::generate_tex(fs_inst *inst, struct brw_reg dst, struct brw_reg src
       brw_set_default_mask_control(p, BRW_MASK_DISABLE);
       brw_set_default_access_mode(p, BRW_ALIGN_1);
 
-      if (memcmp(&surface_reg, &sampler_reg, sizeof(surface_reg)) == 0) {
+      if (brw_regs_equal(&surface_reg, &sampler_reg)) {
          brw_MUL(p, addr, sampler_reg, brw_imm_uw(0x101));
       } else {
          brw_SHL(p, addr, sampler_reg, brw_imm_ud(8));