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authorIan Romanick <[email protected]>2018-06-05 15:04:24 -0700
committerIan Romanick <[email protected]>2018-06-14 11:26:33 -0700
commit461a5c899c08064467abb635536381a5a5659280 (patch)
tree02bc4161194e33add4a95607d89131592c91fcb7 /src/compiler
parent1d92d6486a7685762f480fb33893b3c3db1fd21a (diff)
glsl: Don't copy propagate from SSBO or shared variables either
Since SSBOs can be written by other GPU threads, copy propagating a read can cause the value to magically change. SSBO reads are also very expensive, so doing it twice will be slower. Haswell, Broadwell, and Skylake had similar results. (Skylake shown) total instructions in shared programs: 14399120 -> 14399119 (<.01%) instructions in affected programs: 684 -> 683 (-0.15%) helped: 1 HURT: 0 total cycles in shared programs: 532978931 -> 532973113 (<.01%) cycles in affected programs: 530484 -> 524666 (-1.10%) helped: 1 HURT: 0 Signed-off-by: Ian Romanick <[email protected]> Reviewed-by: Caio Marcelo de Oliveira Filho <[email protected]> Cc: [email protected] Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=106774
Diffstat (limited to 'src/compiler')
-rw-r--r--src/compiler/glsl/opt_copy_propagation.cpp2
1 files changed, 2 insertions, 0 deletions
diff --git a/src/compiler/glsl/opt_copy_propagation.cpp b/src/compiler/glsl/opt_copy_propagation.cpp
index 6220aa86da9..206dffe4f1c 100644
--- a/src/compiler/glsl/opt_copy_propagation.cpp
+++ b/src/compiler/glsl/opt_copy_propagation.cpp
@@ -347,6 +347,8 @@ ir_copy_propagation_visitor::add_copy(ir_assignment *ir)
if (lhs_var != NULL && rhs_var != NULL && lhs_var != rhs_var) {
if (lhs_var->data.mode != ir_var_shader_storage &&
lhs_var->data.mode != ir_var_shader_shared &&
+ rhs_var->data.mode != ir_var_shader_storage &&
+ rhs_var->data.mode != ir_var_shader_shared &&
lhs_var->data.precise == rhs_var->data.precise) {
_mesa_hash_table_insert(acp, lhs_var, rhs_var);
}