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comparison gcc/testsuite/g++.dg/init/strlen.C @ 145:1830386684a0

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gcc-9.2.0
author anatofuz
date Thu, 13 Feb 2020 11:34:05 +0900
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131:84e7813d76e9 145:1830386684a0
1 // Test to verify that the strlen() optimization doesn't make assumptions
2 // about the static type of the object pointed to by its argument. See
3 // the following thread for background:
4 // https://gcc.gnu.org/ml/gcc-patches/2018-08/msg00260.html
5
6 // { dg-do run }
7 // { dg-options "-O2 -Wall -fdump-tree-optimized" }
8
9 typedef __SIZE_TYPE__ size_t;
10
11 void *operator new[] (size_t, void *p) { return p; }
12
13 struct S { int x; char a[1]; char b[64]; };
14
15 __attribute__ ((noipa)) void
16 init (char *s)
17 {
18 *s++ = '1';
19 *s++ = '\0';
20 }
21
22 __attribute__ ((noipa)) void
23 test_dynamic_type (S *p)
24 {
25 // The placement new call below isn't strictly valid because it
26 // creates an object that is larger than the space of the p->a
27 // subobject in which it is created. However, the corresponding
28 // GIMPLE considers it valid and there's apparently no way to
29 // distinguish invalid cases from ones like it that might be valid.
30 // If/when GIMPLE changes to make this possible this test can be
31 // removed.
32 char *q = new (p->a) char [16];
33
34 init (q);
35
36 if (0 == __builtin_strlen (q))
37 __builtin_abort();
38 }
39
40 int main ()
41 {
42 test_dynamic_type (new S);
43 }