When performing common subexpression elimination on instructions with
non-null destinations we emit a MOV to copy the result to a new
register that must have no other uses. In the case of:
cmp.g.f0.0(8) null:D, vgrf43:F, 0.500000f
...
cmp.g.f0.0(8) vgrf113:D, vgrf43:F, 0.500000f
we put the first instruction in the AEB and decided that we could reuse
its result when we found the second. Unfortunately, that meant that we'd
emit a MOV from the first's destination, which is null.
Don't do anything if the entry's destination is null and the
instruction's destination is non-null.
---
Tapani noticed we were hitting an assertion in CSE about entry/inst's
dst types not being the same when running Unreal 4 Sun Temple demo.
src/mesa/drivers/dri/i965/brw_fs_cse.cpp | 3 ++-
src/mesa/drivers/dri/i965/brw_vec4_cse.cpp | 3 ++-
2 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/src/mesa/drivers/dri/i965/brw_fs_cse.cpp
b/src/mesa/drivers/dri/i965/brw_fs_cse.cpp
index f87601c..11cb327 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_cse.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_cse.cpp
@@ -194,7 +194,8 @@ fs_visitor::opt_cse_local(bblock_t *block)
foreach_in_list_use_after(aeb_entry, entry, &aeb) {
/* Match current instruction's expression against those in AEB. */
- if (instructions_match(inst, entry->generator)) {
+ if (!(entry->generator->dst.is_null() && !inst->dst.is_null()) &&
+ instructions_match(inst, entry->generator)) {
found = true;
progress = true;
break;
diff --git a/src/mesa/drivers/dri/i965/brw_vec4_cse.cpp
b/src/mesa/drivers/dri/i965/brw_vec4_cse.cpp
index 30a4098..ee50419 100644
--- a/src/mesa/drivers/dri/i965/brw_vec4_cse.cpp
+++ b/src/mesa/drivers/dri/i965/brw_vec4_cse.cpp
@@ -157,7 +157,8 @@ vec4_visitor::opt_cse_local(bblock_t *block)
foreach_in_list_use_after(aeb_entry, entry, &aeb) {
/* Match current instruction's expression against those in AEB. */
- if (instructions_match(inst, entry->generator)) {
+ if (!(entry->generator->dst.is_null() && !inst->dst.is_null()) &&
+ instructions_match(inst, entry->generator)) {
found = true;
progress = true;
break;
--
2.0.4
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