Module: Mesa Branch: master Commit: 37bd9ccd21b860d2b5ffea7e1f472ec83b68b43b URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=37bd9ccd21b860d2b5ffea7e1f472ec83b68b43b
Author: Ian Romanick <ian.d.roman...@intel.com> Date: Tue Jun 5 16:02:25 2018 -0700 glsl: Don't copy propagate elements from SSBO or shared variables either Since SSBOs can be written by a different GPU thread, copy propagating a read can cause the value to magically change. SSBO reads are also very expensive, so doing it twice will be slower. The same shader was helped by this patch and the previous. Haswell, Broadwell, and Skylake had similar results. (Skylake shown) total instructions in shared programs: 14399119 -> 14399113 (<.01%) instructions in affected programs: 683 -> 677 (-0.88%) helped: 1 HURT: 0 total cycles in shared programs: 532973113 -> 532971865 (<.01%) cycles in affected programs: 524666 -> 523418 (-0.24%) helped: 1 HURT: 0 Signed-off-by: Ian Romanick <ian.d.roman...@intel.com> Reviewed-by: Caio Marcelo de Oliveira Filho <caio.olive...@intel.com> Cc: mesa-sta...@lists.freedesktop.org Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=106774 --- src/compiler/glsl/opt_copy_propagation_elements.cpp | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/src/compiler/glsl/opt_copy_propagation_elements.cpp b/src/compiler/glsl/opt_copy_propagation_elements.cpp index 8bae424a1d..8975e72752 100644 --- a/src/compiler/glsl/opt_copy_propagation_elements.cpp +++ b/src/compiler/glsl/opt_copy_propagation_elements.cpp @@ -544,6 +544,10 @@ ir_copy_propagation_elements_visitor::add_copy(ir_assignment *ir) if (!lhs || !(lhs->type->is_scalar() || lhs->type->is_vector())) return; + if (lhs->var->data.mode == ir_var_shader_storage || + lhs->var->data.mode == ir_var_shader_shared) + return; + ir_dereference_variable *rhs = ir->rhs->as_dereference_variable(); if (!rhs) { ir_swizzle *swiz = ir->rhs->as_swizzle(); @@ -560,6 +564,10 @@ ir_copy_propagation_elements_visitor::add_copy(ir_assignment *ir) orig_swizzle[3] = swiz->mask.w; } + if (rhs->var->data.mode == ir_var_shader_storage || + rhs->var->data.mode == ir_var_shader_shared) + return; + /* Move the swizzle channels out to the positions they match in the * destination. We don't want to have to rewrite the swizzle[] * array every time we clear a bit of the write_mask. _______________________________________________ mesa-commit mailing list mesa-commit@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/mesa-commit
