From: Matt Turner Date: Sat, 28 Mar 2015 00:13:51 +0000 (-0700) Subject: glsl: Reassociate multiplication of mat*mat*vec. X-Git-Tag: upstream/17.1.0~19730 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=2c38f891ad82881cd3cc6e4323bfca7bdb13d13a;p=platform%2Fupstream%2Fmesa.git glsl: Reassociate multiplication of mat*mat*vec. The typical case of mat4*mat4*vec4 is 80 scalar multiplications, but mat4*(mat4*vec4) is only 32. On HSW (with vec4 vertex shaders): instructions in affected programs: 4420 -> 3194 (-27.74%) On BDW (with scalar vertex shaders): instructions in affected programs: 12756 -> 6726 (-47.27%) Implementing a general matrix chain ordering is harder (or at least tedious) because of having to walk the GLSL IR to create a list of multiplicands. I'm guessing that this patch handles 90+% of cases, but of course to tell definitively you'd have to implement the general thing. Reviewed-by: Chris Forbes --- diff --git a/src/glsl/opt_algebraic.cpp b/src/glsl/opt_algebraic.cpp index 98c852a..a940d2f 100644 --- a/src/glsl/opt_algebraic.cpp +++ b/src/glsl/opt_algebraic.cpp @@ -290,6 +290,20 @@ ir_algebraic_visitor::handle_expression(ir_expression *ir) ir_expression *op_expr[4] = {NULL, NULL, NULL, NULL}; unsigned int i; + if (ir->operation == ir_binop_mul && + ir->operands[0]->type->is_matrix() && + ir->operands[1]->type->is_vector()) { + ir_expression *matrix_mul = ir->operands[0]->as_expression(); + + if (matrix_mul && matrix_mul->operation == ir_binop_mul && + matrix_mul->operands[0]->type->is_matrix() && + matrix_mul->operands[1]->type->is_matrix()) { + + return mul(matrix_mul->operands[0], + mul(matrix_mul->operands[1], ir->operands[1])); + } + } + assert(ir->get_num_operands() <= 4); for (i = 0; i < ir->get_num_operands(); i++) { if (ir->operands[i]->type->is_matrix())