From d056863b3c535aeebfe5fcfc9468eb33a06ddb60 Mon Sep 17 00:00:00 2001 From: Matt Turner Date: Fri, 17 Oct 2014 20:32:58 -0700 Subject: [PATCH] glsl: Drop constant 0.0 components from dot products. Helps a small number of vertex shaders in the games Dungeon Defenders and Shank, as well as an internal benchmark. instructions in affected programs: 2801 -> 2719 (-2.93%) Reviewed-by: Kenneth Graunke --- src/glsl/opt_algebraic.cpp | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+) diff --git a/src/glsl/opt_algebraic.cpp b/src/glsl/opt_algebraic.cpp index 0cdb8ecfc0a..c8d1ba1e2f5 100644 --- a/src/glsl/opt_algebraic.cpp +++ b/src/glsl/opt_algebraic.cpp @@ -553,6 +553,33 @@ ir_algebraic_visitor::handle_expression(ir_expression *ir) } return new(mem_ctx) ir_swizzle(ir->operands[0], component, 0, 0, 0, 1); } + + for (int i = 0; i < 2; i++) { + if (!op_const[i]) + continue; + + unsigned components[4] = { 0 }, count = 0; + + for (unsigned c = 0; c < op_const[i]->type->vector_elements; c++) { + if (op_const[i]->value.f[c] == 0.0) + continue; + + components[count] = c; + count++; + } + + /* No channels had zero values; bail. */ + if (count >= op_const[i]->type->vector_elements) + break; + + /* Swizzle both operands to remove the channels that were zero. */ + return new(mem_ctx) + ir_expression(ir_binop_dot, glsl_type::float_type, + new(mem_ctx) ir_swizzle(ir->operands[0], + components, count), + new(mem_ctx) ir_swizzle(ir->operands[1], + components, count)); + } break; case ir_binop_less: -- 2.30.2