PR c++/55137
* fold-const.c (fold_binary_loc) <associate>: Don't introduce
TREE_OVERFLOW through reassociation. If type doesn't have defined
overflow, but one or both of the operands do, use the wrapping type
for reassociation and only convert to type at the end.
* g++.dg/opt/pr55137.C: New test.
* gcc.c-torture/execute/pr55137.c: New test.
From-SVN: r194250
