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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
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 * 2 along with this work; if not, write to the Free Software Foundation,
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package org.graalvm.compiler.nodes.graphbuilderconf;

import jdk.vm.ci.meta.ResolvedJavaMethod;

public interface LoopExplosionPlugin extends GraphBuilderPlugin {

    enum LoopExplosionKind {
        
No loop explosion.
/**
         * No loop explosion.
         */
        NONE(false, false, false, false),
        
Fully unroll all loops. The loops must have a known finite number of iterations. If a
loop has multiple loop ends, they are merged so that the subsequent loop iteration is
processed only once. For example, a loop with 4 iterations and 2 loop ends leads to
1+1+1+1 = 4 copies of the loop body.
/**
         * Fully unroll all loops. The loops must have a known finite number of iterations. If a
         * loop has multiple loop ends, they are merged so that the subsequent loop iteration is
         * processed only once. For example, a loop with 4 iterations and 2 loop ends leads to
         * 1+1+1+1 = 4 copies of the loop body.
         */
        FULL_UNROLL(true, false, false, false),
        
Like FULL_UNROLL, but in addition loop unrolling duplicates loop exits in every iteration instead of merging them. Code after a loop exit is duplicated for every loop exit and every loop iteration. For example, a loop with 4 iterations and 2 loop exits (exit1 and exit2, where exit1 is an early return inside a loop) leads to 4 copies of the loop body and 4 copies of exit1 and 1 copy if exit2. After each exit all code until a return is duplicated per iteration. Beware of break statements inside loops since they cause additional loop exits leading to code duplication along exit2. /**
         * Like {@link #FULL_UNROLL}, but in addition loop unrolling duplicates loop exits in every
         * iteration instead of merging them. Code after a loop exit is duplicated for every loop
         * exit and every loop iteration. For example, a loop with 4 iterations and 2 loop exits
         * (exit1 and exit2, where exit1 is an early return inside a loop) leads to 4 copies of the
         * loop body and 4 copies of exit1 and 1 copy if exit2. After each exit all code until a
         * return is duplicated per iteration. Beware of break statements inside loops since they
         * cause additional loop exits leading to code duplication along exit2.
         */
        FULL_UNROLL_UNTIL_RETURN(true, false, true, false),
        
Fully explode all loops. The loops must have a known finite number of iterations. If a
loop has multiple loop ends, they are not merged so that subsequent loop iterations are
processed multiple times. For example, a loop with 4 iterations and 2 loop ends leads to
1+2+4+8 = 15 copies of the loop body.
/**
         * Fully explode all loops. The loops must have a known finite number of iterations. If a
         * loop has multiple loop ends, they are not merged so that subsequent loop iterations are
         * processed multiple times. For example, a loop with 4 iterations and 2 loop ends leads to
         * 1+2+4+8 = 15 copies of the loop body.
         */
        FULL_EXPLODE(true, true, false, false),
        
Like FULL_EXPLODE, but in addition explosion does not stop at loop exits. Code after the loop is duplicated for every loop exit of every loop iteration. For example, a loop with 4 iterations and 2 loop exits leads to 4 * 2 = 8 copies of the code after the loop. /**
         * Like {@link #FULL_EXPLODE}, but in addition explosion does not stop at loop exits. Code
         * after the loop is duplicated for every loop exit of every loop iteration. For example, a
         * loop with 4 iterations and 2 loop exits leads to 4 * 2 = 8 copies of the code after the
         * loop.
         */
        FULL_EXPLODE_UNTIL_RETURN(true, true, true, false),
        
like FULL_EXPLODE, but copies of the loop body that have the exact same state (all local variables have the same value) are merged. This reduces the number of copies necessary, but can introduce loops again. This kind is useful for bytecode interpreter loops. /**
         * like {@link #FULL_EXPLODE}, but copies of the loop body that have the exact same state
         * (all local variables have the same value) are merged. This reduces the number of copies
         * necessary, but can introduce loops again. This kind is useful for bytecode interpreter
         * loops.
         */
        MERGE_EXPLODE(true, true, false, true);

        private final boolean unrollLoops;
        private final boolean duplicateLoopEnds;
        private final boolean duplicateLoopExits;
        private final boolean mergeLoops;

        LoopExplosionKind(boolean unrollLoops, boolean duplicateLoopEnds, boolean duplicateLoopExits, boolean mergeLoops) {
            this.unrollLoops = unrollLoops;
            assert !duplicateLoopEnds || unrollLoops;
            this.duplicateLoopEnds = duplicateLoopEnds;
            assert !duplicateLoopExits || unrollLoops;
            this.duplicateLoopExits = duplicateLoopExits;
            this.mergeLoops = mergeLoops;
        }

        public boolean unrollLoops() {
            return unrollLoops;
        }

        public boolean duplicateLoopExits() {
            return duplicateLoopExits;
        }

        public boolean duplicateLoopEnds() {
            return duplicateLoopEnds;
        }

        public boolean mergeLoops() {
            return mergeLoops;
        }

        public boolean useExplosion() {
            return this != NONE;
        }

        public boolean isNoExplosion() {
            return this == NONE;
        }
    }

    LoopExplosionKind loopExplosionKind(ResolvedJavaMethod method);
}