libstdc++: avoid bogus -Wrestrict [PR105651]

	PR tree-optimization/105651

libstdc++-v3/ChangeLog:

	* include/bits/basic_string.tcc (_M_replace): Add an assert
	to avoid -Wrestrict false positive.

diff --git a/libstdc++-v3/include/bits/basic_string.tcc b/libstdc++-v3/include/bits/basic_string.tcc
index 0696b96604c168111ae16aa66e245d83d7578c87..48fa28e64668248c8e28584efed71fd051537154 100644 (file)
--- a/libstdc++-v3/include/bits/basic_string.tcc
+++ b/libstdc++-v3/include/bits/basic_string.tcc
@@ -529,6 +529,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
                    {
                      const size_type __nleft = (__p + __len1) - __s;
                      this->_S_move(__p, __s, __nleft);
+                     // Tell the middle-end that the copy can't overlap
+                     // (PR105651).
+                     if (__len2 < __nleft)
+                       __builtin_unreachable();
                      this->_S_copy(__p + __nleft, __p + __len2,
                                    __len2 - __nleft);
                    }