From 8034e7d6f1be3c9c1a9626b64830617ccf000ecc Mon Sep 17 00:00:00 2001 From: Kenneth Graunke Date: Tue, 28 Jul 2015 18:16:37 -0700 Subject: [PATCH] glsl: Convert TES gl_PatchVerticesIn into a constant when using a TCS. MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit When a TCS is present, the TES input gl_PatchVerticesIn is actually a constant - it's simply the # of output vertices specified by the TCS layout qualifiers. So, we can replace the system value with a constant, which may allow further optimization, and will likely be more efficient. If the TCS is absent, we can't do this optimization. Signed-off-by: Kenneth Graunke Reviewed-by: Marek Olšák --- src/glsl/linker.cpp | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/src/glsl/linker.cpp b/src/glsl/linker.cpp index 424b92a1783..cfd8f81c867 100644 --- a/src/glsl/linker.cpp +++ b/src/glsl/linker.cpp @@ -2282,6 +2282,22 @@ resize_tes_inputs(struct gl_context *ctx, foreach_in_list(ir_instruction, ir, tes->ir) { ir->accept(&input_resize_visitor); } + + if (tcs) { + /* Convert the gl_PatchVerticesIn system value into a constant, since + * the value is known at this point. + */ + foreach_in_list(ir_instruction, ir, tes->ir) { + ir_variable *var = ir->as_variable(); + if (var && var->data.mode == ir_var_system_value && + var->data.location == SYSTEM_VALUE_VERTICES_IN) { + void *mem_ctx = ralloc_parent(var); + var->data.mode = ir_var_auto; + var->data.location = 0; + var->constant_value = new(mem_ctx) ir_constant(num_vertices); + } + } + } } /** -- 2.30.2