https://gcc.gnu.org/bugzilla/show_bug.cgi?id=119577
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Last reconfirmed| |2025-04-02
Status|UNCONFIRMED |NEW
CC| |rguenth at gcc dot gnu.org,
| |tnfchris at gcc dot gnu.org
Ever confirmed|0 |1
--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
Well, risc-v is the only arch with that .SELECT_VL, that is, a vector length
that might change between iterations. For other archs the IV increments
by a (poly-)constant.
But sure, it might be possible to code-generate those unused-but-live
IVs as scalars:
t.c:8:23: note: init: phi relevant? i_10 = PHI <i_7(8), 1(7)>
t.c:8:23: note: vec_stmt_relevant_p: used out of loop.
t.c:8:23: note: vec_stmt_relevant_p: induction forced for early break.
t.c:8:23: note: vec_stmt_relevant_p: stmt live but not relevant.
IIRC it depends on the "kind" of early break whether we need the
first IV (scalar IV possible) or the last, but I don't rememeber exactly.
