https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103325
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Last reconfirmed| |2021-11-19
Ever confirmed|0 |1
--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
I think we used to constant fold this as 1<<1. GCC 7 does
> gcc-7 -S t.c -fdump-tree-original
t.c: In function 'main':
t.c:2:12: warning: right shift count is negative [-Wshift-count-negative]
return 1 >> (-1);
^~
> cat t.c.003t.original
;; Function main (null)
;; enabled by -tree-original
{
return 2;
}
return 0;
but IIRC that behavior was removed from {int_const,wide}_int_binop at some
point, maybe also to enable sanitization.
gimple-ssa-isolate-paths.c would be one place to turn such code into
unreachable or traps (see other PRs to make the behavior configurable).
