> I would like to again ping the patch posted in
> https://gcc.gnu.org/pipermail/gcc-patches/2025-November/700704.html
>
> Add hierarchical discriminator support for loop unrolling.
> Assigns multiplicity and copyid discriminators to distinguish unrolled
> iterations.
>
> gcc/ChangeLog:
>
> * cfgloopmanip.cc (duplicate_loop_body_to_header_edge): Assign
> hierarchical discriminators for loop unrolling.
> * cfgloopmanip.h (DLTHE_RECORD_HIERARCHICAL_DISCRIMINATOR): New flag.
> * tree-ssa-loop-ivcanon.cc (try_unroll_loop_completely): Pass flag
> to enable hierarchical discriminator assignment.
> (try_peel_loop): Likewise.
>
> gcc/testsuite/ChangeLog:
>
> * gcc.dg/hierarchical-discriminator-unroll.c: New test.
+ unsigned int loop_copyid_base = 0;
+ if (current_ir_type () == IR_GIMPLE)
+ {
..
+ }
+ else
+ {
+ /* For RTL, try to find an instruction with a valid location.
+ Be defensive to avoid crashes on invalid/corrupted insns. */
+ rtx_insn *insn = BB_END (loop->header);
+ while (insn && insn != BB_HEAD (loop->header))
+ {
+ /* Only check location if this is a valid insn. */
+ if (INSN_P (insn))
+ {
+ location_t loc = INSN_LOCATION (insn);
+ if (loc != UNKNOWN_LOCATION)
+ {
+ loop_loc = get_pure_location (loc);
+ break;
+ }
+ }
+ insn = PREV_INSN (insn);
+ }
+ }
+
...
+ if (current_ir_type () == IR_GIMPLE)
+ {
....
+ }
+ else
+ {
+ /* Only assign discriminators if we successfully allocated
+ a copyid base. */
+ if (loop_copyid_base > 0)
This will never be true. But I think the copyid allocation can work
both on RTL and Gimple. You will need to support initializing the
allocator at RTL level too if necessary, but both is just a siple walk
of a function body.
Honza
