https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68346
Bug ID: 68346
Summary: [6 Regression] Bootstrap failure on i686-linux
Product: gcc
Version: 6.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: bootstrap
Assignee: unassigned at gcc dot gnu.org
Reporter: jakub at gcc dot gnu.org
Target Milestone: ---
Most likely since the c++ delayed folding merge, but I admit I've bootstrapped
trunk on i686-linux 8 days ago, so the window is larger, trunk no longer
bootstraps on i686-linux:
../../gcc/gimple-fold.c: In function ‘bool
gimple_fold_builtin_printf(gimple_stmt_iterator*, tree, tree,
built_in_function)’:
../../gcc/gimple-fold.c:2621:30: error: self-comparison always evaluates to
true [-Werror=tautological-compare]
&& (size_t) (int) len == len
^~
This code is not new in there, but supposedly before that we either have not
been folding the arguments for -Wtautological-compare, or not so aggressively.
I'd say it is quite common idiom to cast a variable to some other type and
compare to itself, with the intent that if the type is the same, it is a no-op
check, but if the type is narrower or has different signedness, it filters out
some undesirable values.
