ir_function_can_inline.cpp

/*
 * Copyright © 2010 Intel Corporation
 *
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 * copy of this software and associated documentation files (the "Software"),
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 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
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 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
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/**
 * \file ir_function_can_inline.cpp
 *
 * Determines if we can inline a function call using ir_function_inlining.cpp.
 *
 * The primary restriction is that we can't return from the function
 * other than as the last instruction.  We could potentially work
 * around this for some constructs by flattening control flow and
 * moving the return to the end, or by using breaks from a do {} while
 * (0) loop surrounding the function body.
 */

#define NULL 0
#include "ir.h"

class ir_function_can_inline_visitor : public ir_hierarchical_visitor {
public:
   ir_function_can_inline_visitor()
   {
      this->can_inline = true;
      this->num_returns = 0;
   }

   virtual ir_visitor_status visit_enter(ir_loop *);
   virtual ir_visitor_status visit_enter(ir_return *);
   virtual ir_visitor_status visit_enter(ir_if *);

   bool can_inline;
   int num_returns;
};

ir_visitor_status
ir_function_can_inline_visitor::visit_enter(ir_loop *ir)
{
   /* FINISHME: Implement loop cloning in ir_function_inlining.cpp */
   (void) ir;
   this->can_inline = false;
   return visit_stop;
}


ir_visitor_status
ir_function_can_inline_visitor::visit_enter(ir_return *ir)
{
   (void) ir;
   this->num_returns++;
   return visit_continue;
}


ir_visitor_status
ir_function_can_inline_visitor::visit_enter(ir_if *ir)
{
   /* FINISHME: Implement if cloning in ir_function_inlining.cpp. */
   (void) ir;
   this->can_inline = false;
   return visit_stop;
}

bool
can_inline(ir_call *call)
{
   ir_function_can_inline_visitor v;
   const ir_function_signature *callee = call->get_callee();

   v.run((exec_list *) &callee->body);

   ir_instruction *last = (ir_instruction *)callee->body.get_tail();
   if (last && !last->as_return())
      v.num_returns++;

   return v.can_inline && v.num_returns == 1;
}