[Bug c++/55095] Wshift-overflow

[joseph at codesourcery dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55095

--- Comment #4 from joseph at codesourcery dot com <joseph at codesourcery dot com> 2012-10-28 17:58:55 UTC ---
The constant folder (fold-const.c:int_const_binop_1) would seem to be the 
place where overflow information would most readily be available for this: 
as I understand it, it's specifically about constants, rather than the 
generic issue that almost any left shift with nonconstant operands might 
overflow.  If diagnosing there, you'd want to pass down a location a few 
levels from fold_binary_loc (so changing lots of calls to const_binop to 
pass a location).

(In any case, double-int will need a new interface to report whether shift 
overflow has occurred.)