llvm-project

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#!/usr/bin/env python
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"""A ladder graph creation program.
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This is a python program that creates c source code that will generate
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CFGs that are ladder graphs.  Ladder graphs are generally the worst case
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for a lot of dominance related algorithms (Dominance frontiers, etc),
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and often generate N^2 or worse behavior.
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One good use of this program is to test whether your linear time algorithm is
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really behaving linearly.
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"""
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from __future__ import print_function
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import argparse
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def main():
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    parser = argparse.ArgumentParser(description=__doc__)
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    parser.add_argument(
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        "rungs", type=int, help="Number of ladder rungs. Must be a multiple of 2"
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    )
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    args = parser.parse_args()
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    if (args.rungs % 2) != 0:
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        print("Rungs must be a multiple of 2")
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        return
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    print("int ladder(int *foo, int *bar, int x) {")
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    rung1 = range(0, args.rungs, 2)
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    rung2 = range(1, args.rungs, 2)
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    for i in rung1:
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        print("rung1%d:" % i)
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        print("*foo = x++;")
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        if i != rung1[-1]:
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            print("if (*bar) goto rung1%d;" % (i + 2))
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            print("else goto rung2%d;" % (i + 1))
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        else:
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            print("goto rung2%d;" % (i + 1))
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    for i in rung2:
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        print("rung2%d:" % i)
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        print("*foo = x++;")
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        if i != rung2[-1]:
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            print("goto rung2%d;" % (i + 2))
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        else:
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            print("return *foo;")
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    print("}")
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if __name__ == "__main__":
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    main()
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