From 3c22e3516527ccb83f2667abfa0e6518c5938df8 Mon Sep 17 00:00:00 2001 From: Kenneth Graunke Date: Thu, 22 Sep 2011 15:04:56 -0700 Subject: [PATCH] glsl: Stop tree grafting if a variable is overwritten as an 'out' param. While reviewing some compiler cleanups I'd sent out, Paul noticed that tree grafting wasn't taking "out" parameters into account. Further investigation revealed that it isn't strictly necessary: ir_call ends basic blocks, and tree grafting currently only operates on basic blocks. So calls already kill grafts. However, just to be safe, this patch makes "out" parameters explicitly kill grafts. Paul and I both prefer this. It's a bit clearer. Signed-off-by: Kenneth Graunke Reviewed-by: Paul Berry --- src/glsl/opt_tree_grafting.cpp | 39 ++++++++++++++++++++++++---------- 1 file changed, 28 insertions(+), 11 deletions(-) diff --git a/src/glsl/opt_tree_grafting.cpp b/src/glsl/opt_tree_grafting.cpp index 22a1749b9dd..d32d14e88a9 100644 --- a/src/glsl/opt_tree_grafting.cpp +++ b/src/glsl/opt_tree_grafting.cpp @@ -76,6 +76,8 @@ public: virtual ir_visitor_status visit_enter(class ir_swizzle *); virtual ir_visitor_status visit_enter(class ir_texture *); + ir_visitor_status check_graft(ir_instruction *ir, ir_variable *var); + bool do_graft(ir_rvalue **rvalue); bool progress; @@ -148,18 +150,17 @@ ir_tree_grafting_visitor::visit_enter(ir_loop *ir) return visit_stop; } +/** + * Check if we can continue grafting after writing to a variable. If the + * expression we're trying to graft references the variable, we must stop. + * + * \param ir An instruction that writes to a variable. + * \param var The variable being updated. + */ ir_visitor_status -ir_tree_grafting_visitor::visit_leave(ir_assignment *ir) +ir_tree_grafting_visitor::check_graft(ir_instruction *ir, ir_variable *var) { - if (do_graft(&ir->rhs) || - do_graft(&ir->condition)) - return visit_stop; - - /* If this assignment updates a variable used in the assignment - * we're trying to graft, then we're done. - */ - if (dereferences_variable(this->graft_assign->rhs, - ir->lhs->variable_referenced())) { + if (dereferences_variable(this->graft_assign->rhs, var)) { if (debug) { printf("graft killed by: "); ir->print(); @@ -171,6 +172,19 @@ ir_tree_grafting_visitor::visit_leave(ir_assignment *ir) return visit_continue; } +ir_visitor_status +ir_tree_grafting_visitor::visit_leave(ir_assignment *ir) +{ + if (do_graft(&ir->rhs) || + do_graft(&ir->condition)) + return visit_stop; + + /* If this assignment updates a variable used in the assignment + * we're trying to graft, then we're done. + */ + return check_graft(ir, ir->lhs->variable_referenced()); +} + ir_visitor_status ir_tree_grafting_visitor::visit_enter(ir_function *ir) { @@ -195,8 +209,11 @@ ir_tree_grafting_visitor::visit_enter(ir_call *ir) ir_rvalue *ir = (ir_rvalue *)iter.get(); ir_rvalue *new_ir = ir; - if (sig_param->mode != ir_var_in && sig_param->mode != ir_var_const_in) + if (sig_param->mode != ir_var_in && sig_param->mode != ir_var_const_in) { + if (check_graft(ir, sig_param) == visit_stop) + return visit_stop; continue; + } if (do_graft(&new_ir)) { ir->replace_with(new_ir); -- 2.30.2