From: Ian Romanick Date: Tue, 5 Jun 2018 22:04:24 +0000 (-0700) Subject: glsl: Don't copy propagate from SSBO or shared variables either X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=461a5c899c08064467abb635536381a5a5659280;p=mesa.git 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 Reviewed-by: Caio Marcelo de Oliveira Filho Cc: mesa-stable@lists.freedesktop.org Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=106774 --- 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); }