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145
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1 /* PR tree-optimization/83821 - local aggregate initialization defeats
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2 strlen optimization
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3 Verify that a strlen() call is eliminated for a pointer to a region
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4 of memory allocated by calloc() even if one or more nul bytes are
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5 written into it.
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6 { dg-do compile }
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7 { dg-options "-O2 -fdump-tree-optimized" } */
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8
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9 unsigned n0, n1;
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10
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11 void* elim_strlen_calloc_store_memset_1 (unsigned a, unsigned b)
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12 {
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13 char *p = __builtin_calloc (a, 1);
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14
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15 p[0] = '\0';
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16 p[1] = '\0';
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17 p[2] = '\0';
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18 p[3] = '\0';
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19
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20 __builtin_memset (p, 0, b);
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21
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22 n0 = __builtin_strlen (p);
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23
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24 return p;
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25 }
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26
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27 void* elim_strlen_calloc_store_memset_2 (unsigned a, unsigned b, unsigned c)
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28 {
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29 char *p = __builtin_calloc (a, 1);
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30
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31 p[1] = '\0';
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32 __builtin_memset (p, 0, b);
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33
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34 n0 = __builtin_strlen (p);
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35
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36 p[3] = 0;
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37 __builtin_memset (p, 0, c);
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38
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39 n1 = __builtin_strlen (p);
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40
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41 return p;
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42 }
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43
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44 /* { dg-final { scan-tree-dump-not "__builtin_strlen" "optimized" } } */
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