Opened 7 months ago
Last modified 7 months ago
#69374 new defect
gcc13 optimizer bug in ncurses — at Initial Version
| Reported by: | ThomasDickey (Thomas Dickey) | Owned by: | |
|---|---|---|---|
| Priority: | Normal | Milestone: | |
| Component: | ports | Version: | |
| Keywords: | Cc: | ||
| Port: | gcc13 |
Description
I noticed a problem in ncurses not displaying multibyte characters (used in line-drawing), and narrowed it down to a problem optimizing an expression in tty_update.c, using this chunk(https://github.com/ThomasDickey/ncurses-snapshots/blob/a98f459acb17efd5c1754d12efdfeba8cdb70e68/ncurses/curses.priv.h#L1458):
} else { \
int PUTC_j; \ for (PUTC_j = 0; PUTC_j < PUTC_n; ++PUTC_j) { \
TR_PUTC(PUTC_buf[PUTC_j]); \ NCURSES_OUTC_FUNC (NCURSES_SP_ARGx PUTC_buf[PUTC_j]); \
} \
} \
PUTC(CHDEREF(ch));
There's no issue reported in valgrind, address sanitizer, etc., in other environments, which would indicate a problem in ncurses, but with optimization that goes through the loop the expected number of times but fails to call the output NCURSES_OUTC_FUNC more than once.
If it helps, I can attach the generated assembly for gcc12 (working) and gcc13 (nonworking).