0fd80b12df
GCC 6 `std::sort` sometimes compares an element to itself. For a normal
implementation of comparison, this is useless, but not harmful. The
render comparison predicate relies on accessing A[B[a][b]] when
comparing `a` and `b`. Array `B` has `-1` in positions where `a == b`,
which causes an access to `A[-1]`, which is undefined behavior. This
crashes when using _GLIBCXX_DEBUG:
Error: attempt to subscript container with out-of-bounds index -1, but
container only holds 8 elements.
Objects involved in the operation:
sequence "this" @ 0x0x335adf0 {
type = std::__debug::array<int, 8ul>::_Array_check_subscript<8ul>;
}
Since this is undefined behavior, non-debug builds might also misbehave.
Current data layouts make it likely that the failure would not have
externally observable consequences.
Prevent the invalid access by short-circuiting the result if `a == b`.
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| common | ||
| contrib | ||
| d1x-rebirth | ||
| d2x-rebirth | ||
| Documentation | ||
| similar | ||
| .gitignore | ||
| COPYING.txt | ||
| GPL-3.txt | ||
| INSTALL.markdown | ||
| SConstruct | ||