Coverage Report

Created: 2017-11-23 03:11

/Users/buildslave/jenkins/workspace/clang-stage2-coverage-R/llvm/tools/polly/lib/External/isl/isl_sort.c
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/*
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 * The code of this file was taken from http://jeffreystedfast.blogspot.be,
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 * where it was posted in 2011 by Jeffrey Stedfast under the MIT license.
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 * The MIT license text is as follows:
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 *
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 * Permission is hereby granted, free of charge, to any person obtaining a copy
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 * of this software and associated documentation files (the "Software"), to
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 * deal in the Software without restriction, including without limitation the
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 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
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 * sell copies of the Software, and to permit persons to whom the Software is
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 * furnished to do so, subject to the following conditions:
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 *
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 * The above copyright notice and this permission notice shall be included in
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 * all copies or substantial portions of the Software.
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 *
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 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
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 * IN THE SOFTWARE.
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 */
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#include <errno.h>
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#include <string.h>
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#include <stdlib.h>
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#include <isl_sort.h>
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#define MID(lo, hi) (lo + ((hi - lo) >> 1))
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/* The code here is an optimized merge sort. Starting from a generic merge sort
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 * the following optimizations were applied:
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 *
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 * o Batching of memcpy() calls: Instead of calling memcpy() to copy each and
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 *   every element into a temporary buffer, blocks of elements are copied
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 *   at a time.
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 *
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 * o To reduce the number of memcpy() calls further, copying leading
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 *   and trailing elements into our temporary buffer is avoided, in case it is
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 *   not necessary to merge them.
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 *
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 * A further optimization could be to specialize memcpy calls based on the
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 * size of the types we compare. For now, this code does not include the
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 * relevant optimization, as clang e.g. inlines a very efficient memcpy()
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 * implementation. It is not clear, that the specialized version as provided in
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 * the blog post, is really superior to the one that will be inlined by
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 * default. So we decided to keep the code simple until this optimization was
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 * proven to be beneficial.
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 */
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static void
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msort (void *array, void *buf, size_t low, size_t high, size_t size,
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       int (* compare) (const void *, const void *, void *), void *arg)
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{
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    char *a1, *al, *am, *ah, *ls, *hs, *lo, *hi, *b;
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    size_t copied = 0;
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    size_t mid;
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    mid = MID (low, high);
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    if (mid + 1 < high)
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        msort (array, buf, mid + 1, high, size, compare, arg);
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    if (mid > low)
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        msort (array, buf, low, mid, size, compare, arg);
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    ah = ((char *) array) + ((high + 1) * size);
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    am = ((char *) array) + ((mid + 1) * size);
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    a1 = al = ((char *) array) + (low * size);
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    b = (char *) buf;
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    lo = al;
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    hi = am;
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    do {
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        ls = lo;
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        hs = hi;
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        if (lo > al || 
hi > am1.19M
) {
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            /* our last loop already compared lo & hi and found lo <= hi */
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            lo += size;
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        }
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        while (lo < am && 
compare (lo, hi, arg) <= 02.40M
)
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            lo += size;
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        if (lo < am) {
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            if (copied == 0) {
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                /* avoid copying the leading items */
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                a1 = lo;
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                ls = lo;
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            }
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            /* our last compare tells us hi < lo */
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            hi += size;
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            while (hi < ah && 
compare (hi, lo, arg) < 0408k
)
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hi += size267k
;
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            if (lo > ls) {
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                memcpy (b, ls, lo - ls);
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                copied += (lo - ls);
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                b += (lo - ls);
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            }
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            memcpy (b, hs, hi - hs);
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            copied += (hi - hs);
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            b += (hi - hs);
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        } else if (copied) {
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            memcpy (b, ls, lo - ls);
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            copied += (lo - ls);
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            b += (lo - ls);
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            /* copy everything we needed to re-order back into array */
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            memcpy (a1, buf, copied);
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            return;
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        } else {
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            /* everything already in order */
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            return;
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        }
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    } while (hi < ah);
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if (239k
lo < am239k
) {
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        memcpy (b, lo, am - lo);
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        copied += (am - lo);
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    }
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    memcpy (a1, buf, copied);
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}
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static int
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MergeSort (void *base, size_t nmemb, size_t size,
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           int (* compare) (const void *, const void *, void *), void *arg)
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{
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    void *tmp;
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    if (nmemb < 2)
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        return 0;
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    if (!(tmp = malloc (nmemb * size))) {
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        errno = ENOMEM;
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        return -1;
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    }
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    msort (base, tmp, 0, nmemb - 1, size, compare, arg);
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    free (tmp);
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    return 0;
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}
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int isl_sort(void *const pbase, size_t total_elems, size_t size,
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  int (*cmp)(const void *, const void *, void *arg), void *arg)
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{
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    return MergeSort (pbase, total_elems, size, cmp, arg);
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}