On Wed, 10 Jun 2026, Tamar Christina wrote:
> Similar to the mask control variable, this replaces and adds the temporary SSA
> var for early break scalar IVs with an IFN_VARYING until the replacement is
> done
> when we start vectorization.
>
> This prevents similar issues as the mask control variable when the IV
> expressions are folded.
>
> Bootstrapped Regtested on aarch64-none-linux-gnu,
> arm-none-linux-gnueabihf, x86_64-pc-linux-gnu
> -m32, -m64 and no issues.
>
> Any comments? Does this do what you expected Richi?
Yes.
Thanks,
Richard.
> Thanks,
> Tamar
>
> gcc/ChangeLog:
>
> PR tree-optimization/125597
> * tree-vect-loop-manip.cc (vect_do_peeling): Create IFN_VARYING for
> early break scalar IV.
> * tree-vect-loop.cc (vect_update_ivs_after_vectorizer_for_early_breaks):
> Replace the IFN_VARYING with actual value.
>
> ---
> diff --git a/gcc/tree-vect-loop-manip.cc b/gcc/tree-vect-loop-manip.cc
> index
> 4a3444966acf5d66394196caf24dc3ba2fa63ec3..d2c854e16d4413dc26ab1ec35d20633ef415d01c
> 100644
> --- a/gcc/tree-vect-loop-manip.cc
> +++ b/gcc/tree-vect-loop-manip.cc
> @@ -3841,6 +3841,10 @@ vect_do_peeling (loop_vec_info loop_vinfo, tree
> niters, tree nitersm1,
> {
> tree tmp_niters_vf
> = make_ssa_name (LOOP_VINFO_EARLY_BRK_IV_TYPE (loop_vinfo));
> + gcall *tmp_call = gimple_build_call_internal (IFN_VARYING, 0);
> + gimple_call_set_lhs (tmp_call, tmp_niters_vf);
> + auto header_gsi = gsi_after_labels (loop->header);
> + gsi_insert_after (&header_gsi, tmp_call, GSI_SAME_STMT);
>
> if (!(LOOP_VINFO_NITERS_UNCOUNTED_P (loop_vinfo)
> && get_loop_exit_edges (loop).length () == 1)
> diff --git a/gcc/tree-vect-loop.cc b/gcc/tree-vect-loop.cc
> index
> 51e7f05100de7ab31994f3b4a30f5c5be8d8afdd..4d9b691c3299ce08fc0946d9065e3cdead816d8a
> 100644
> --- a/gcc/tree-vect-loop.cc
> +++ b/gcc/tree-vect-loop.cc
> @@ -11079,6 +11079,11 @@ vect_update_ivs_after_vectorizer_for_early_breaks
> (loop_vec_info loop_vinfo)
> auto loop = LOOP_VINFO_LOOP (loop_vinfo);
> tree induc_var = niters_skip ? copy_ssa_name (phi_var) : phi_var;
>
> + /* Remove the existing dummy GIMPLE statement and just keep the def. */
> + gimple *def = SSA_NAME_DEF_STMT (phi_var);
> + auto def_gsi = gsi_for_stmt (def);
> + gsi_remove (&def_gsi, true);
> +
> auto induction_phi = create_phi_node (induc_var, loop->header);
> tree induc_def = PHI_RESULT (induction_phi);
>
> @@ -11149,7 +11154,7 @@ vect_update_ivs_after_vectorizer_for_early_breaks
> (loop_vec_info loop_vinfo)
> gcc_assert (exit_bb);
> auto exit_gsi = gsi_after_labels (exit_bb);
> gsi_insert_seq_before (&exit_gsi, iv_stmts, GSI_SAME_STMT);
> - }
> + }
> /* Write the init_stmts in the loop-preheader block. */
> auto psi = gsi_last_nondebug_bb (pe->src);
> gsi_insert_seq_after (&psi, init_stmts, GSI_LAST_NEW_STMT);
>
>
>
--
Richard Biener <[email protected]>
SUSE Software Solutions Germany GmbH,
Frankenstrasse 146, 90461 Nuernberg, Germany;
GF: Jochen Jaser, Andrew McDonald, Werner Knoblich; (HRB 36809, AG Nuernberg)
