https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88660
Martin Sebor <msebor at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Last reconfirmed| |2019-09-29
CC| |msebor at gcc dot gnu.org
Known to work| |7.3.0
Blocks| |89180
Summary|Invalid report of "set but |[8/9/10 Regression] Invalid
|used variable" with -O |report of "set but used
| |variable" with -O
Ever confirmed|0 |1
Known to fail| |10.0, 8.3.0, 9.2.0
--- Comment #1 from Martin Sebor <msebor at gcc dot gnu.org> ---
Confirmed. Bisection points to r254930 as the revision that caused the
regression:
r254930 | jakub | 2017-11-19 12:17:01 -0500 (Sun, 19 Nov 2017) | 28 lines
PR c/66618
PR c/69960
c-family/
* c-common.h (c_fully_fold): Add LVAL argument defaulted to false.
c/
* c-parser.c (c_parser_omp_atomic): Pass true as LVAL to c_fully_fold
where needed.
* c-typeck.c (build_unary_op, build_modify_expr, build_asm_expr,
handle_omp_array_sections): Likewise.
(digest_init): Don't call decl_constant_value_for_optimization.
* c-tree.h (decl_constant_value_for_optimization): Removed.
* c-fold.c (c_fold_array_ref): New function.
(c_fully_fold_internal): Add LVAL argument, propagate it through
recursive calls. For VAR_P call decl_constant_value and
unshare if not LVAL and either optimizing or IN_INIT. Remove
decl_constant_value_for_optimization calls. If IN_INIT and not LVAL,
fold ARRAY_REF with STRING_CST and INTEGER_CST operands.
(c_fully_fold): Add LVAL argument, pass it through to
c_fully_fold_internal.
(decl_constant_value_for_optimization): Removed.
cp/
* cp-gimplify.c (c_fully_fold): Add LVAL argument, call
cp_fold_maybe_rvalue instead of cp_fold_rvalue and pass it !LVAL.
Referenced Bugs:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89180
[Bug 89180] [meta-bug] bogus/missing -Wunused warnings
