org.jikesrvm.compilers.opt.ssa

Class RedundantBranchElimination.RBE

java.lang.Object

org.jikesrvm.compilers.opt.driver.CompilerPhase

org.jikesrvm.compilers.opt.ssa.RedundantBranchElimination.RBE

Enclosing class:

RedundantBranchElimination

private static final class RedundantBranchElimination.RBE
extends CompilerPhase

Field Summary

Fields

Modifier and Type	Field and Description
private static boolean	DEBUG

Fields inherited from class org.jikesrvm.compilers.opt.driver.CompilerPhase

container

Constructor Summary

Constructors

Modifier	Constructor and Description
private	RBE()

Method Summary

Modifier and Type	Method and Description
String	getName()
private BasicBlock	getNotTakenBlock(Instruction s)
CompilerPhase	newExecution(IR ir) Return this instance of this phase.
void	perform(IR ir) Transform to eliminate redundant branches passed on GVNs and dominator information.
boolean	printingEnabled(OptOptions options, boolean before) Returns true if the phase wants the IR dumped before and/or after it runs.
private void	removeCondBranch(BasicBlock source, Instruction cb, IR ir, Instruction di) Remove cb from source, updating PHI nodes to maintain SSA form.
private void	removeUnreachableCode(IR ir) Remove unreachable code
private void	takeCondBranch(BasicBlock source, Instruction cb, IR ir) Transforms a conditional branch into a GOTO, updating PHI nodes to maintain SSA form.

Methods inherited from class org.jikesrvm.compilers.opt.driver.CompilerPhase

dumpIR, dumpIR, getClassConstructor, getCompilerPhaseConstructor, getCompilerPhaseConstructor, performPhase, reportAdditionalStats, setContainer, shouldPerform, verify

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

DEBUG

private static final boolean DEBUG

See Also:

Constant Field Values

Constructor Detail

RBE

private RBE()

Method Detail

getName

public String getName()

Specified by:

getName in class CompilerPhase

Returns:

a String which is the name of the phase.

printingEnabled

public boolean printingEnabled(OptOptions options,
                               boolean before)

Description copied from class: CompilerPhase

Returns true if the phase wants the IR dumped before and/or after it runs. By default, printing is not enabled. Subclasses should override this method if they want to provide IR dumping.

Overrides:

printingEnabled in class CompilerPhase

Parameters:

options - the compiler options for the compilation

before - true when invoked before perform, false otherwise.

Returns:

true if the IR should be printed, false otherwise.

newExecution

public CompilerPhase newExecution(IR ir)

Return this instance of this phase. This phase contains no per-compilation instance fields.

Overrides:

newExecution in class CompilerPhase

Parameters:

ir - not used

Returns:

this

perform

public void perform(IR ir)

Transform to eliminate redundant branches passed on GVNs and dominator information.

Specified by:

perform in class CompilerPhase

Parameters:

ir - The IR on which to apply the phase

removeUnreachableCode

private void removeUnreachableCode(IR ir)

Remove unreachable code

Parameters:

ir - the IR to optimize

getNotTakenBlock

private BasicBlock getNotTakenBlock(Instruction s)

Parameters:

s - an instruction instruction

Returns:

the basic block that s's block will goto if s is not taken.

removeCondBranch

private void removeCondBranch(BasicBlock source,
                              Instruction cb,
                              IR ir,
                              Instruction di)

Remove cb from source, updating PHI nodes to maintain SSA form.

Parameters:

source - basic block containing cb

cb - conditional branch to remove

ir - containing IR

di - branch that dominates cb

takeCondBranch

private void takeCondBranch(BasicBlock source,
                            Instruction cb,
                            IR ir)

Transforms a conditional branch into a GOTO, updating PHI nodes to maintain SSA form.

Parameters:

source - the basic block that contains the branch instruction

cb - the conditional branch to transform

ir - the governing IR, in SSA form