/*
* Copyright (c) 2009-2011, IETR/INSA of Rennes
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* * Neither the name of the IETR/INSA of Rennes nor the names of its
* contributors may be used to endorse or promote products derived from this
* software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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*/
package net.sf.orcc.backends.transform.ssa;
import net.sf.orcc.ir.ExprVar;
import net.sf.orcc.ir.InstAssign;
import net.sf.orcc.ir.Procedure;
import net.sf.orcc.ir.Use;
import net.sf.orcc.ir.Var;
import net.sf.orcc.ir.util.AbstractIrVisitor;
import net.sf.orcc.ir.util.IrUtil;
import net.sf.orcc.util.Void;
import org.eclipse.emf.common.util.EList;
import org.eclipse.emf.ecore.util.EcoreUtil;
/**
* Replace occurrences with direct assignments to their corresponding values. A
* direct assignment is an assign instruction of form x = y, which simply
* assigns the value of y to x.
*
* @author Jerome GORIN
* @author Herve Yviquel
*
*/
public class CopyPropagator extends AbstractIrVisitor<Void> {
protected boolean changed;
@Override
public Void caseProcedure(Procedure procedure) {
do {
changed = false;
super.caseProcedure(procedure);
} while (changed);
return null;
}
@Override
public Void caseInstAssign(InstAssign assign) {
if (assign.getValue().isExprVar()) {
Var source = ((ExprVar) assign.getValue()).getUse().getVariable();
Var target = assign.getTarget().getVariable();
EList<Use> targetUses = target.getUses();
changed = true;
while (!targetUses.isEmpty()) {
targetUses.get(0).setVariable(source);
}
EcoreUtil.remove(target);
IrUtil.delete(assign);
indexInst--;
}
return null;
}
}