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tree-optimization/113026 - fix vector epilogue maximum iter bound

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The late amendment with a limit based on VF was redundant and wrong
for peeled early exits.  The following moves the adjustment done
when we don't have a skip edge down to the place where the already
existing VF based max iter check is done and removes the amendment.

	PR tree-optimization/113026
	* tree-vect-loop-manip.cc (vect_do_peeling): Remove
	redundant and wrong niter bound setting.  Move niter
	bound adjustment down.
This commit is contained in:
Richard Biener 2024-01-09 11:49:50 +01:00
parent aaa9467618
commit c22cf7a7a7
1 changed files with 15 additions and 32 deletions
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47
gcc/tree-vect-loop-manip.cc
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@ -3383,38 +3383,6 @@ vect_do_peeling (loop_vec_info loop_vinfo, tree niters, tree nitersm1,
bb_before_epilog->count = single_pred_edge (bb_before_epilog)->count ();
bb_before_epilog = loop_preheader_edge (epilog)->src;
}
else
{
/* When we do not have a loop-around edge to the epilog we know
the vector loop covered at least VF scalar iterations unless
we have early breaks and the epilog will cover at most
VF - 1 + gap peeling iterations.
Update any known upper bound with this knowledge. */
if (! LOOP_VINFO_EARLY_BREAKS (loop_vinfo))
{
if (epilog->any_upper_bound)
epilog->nb_iterations_upper_bound -= lowest_vf;
if (epilog->any_likely_upper_bound)
epilog->nb_iterations_likely_upper_bound -= lowest_vf;
if (epilog->any_estimate)
epilog->nb_iterations_estimate -= lowest_vf;
}
unsigned HOST_WIDE_INT const_vf;
if (vf.is_constant (&const_vf))
{
const_vf += LOOP_VINFO_PEELING_FOR_GAPS (loop_vinfo) - 1;
if (epilog->any_upper_bound)
epilog->nb_iterations_upper_bound
= wi::umin (epilog->nb_iterations_upper_bound, const_vf);
if (epilog->any_likely_upper_bound)
epilog->nb_iterations_likely_upper_bound
= wi::umin (epilog->nb_iterations_likely_upper_bound,
const_vf);
if (epilog->any_estimate)
epilog->nb_iterations_estimate
= wi::umin (epilog->nb_iterations_estimate, const_vf);
}
}
/* If loop is peeled for non-zero constant times, now niters refers to
orig_niters - prolog_peeling, it won't overflow even the orig_niters
@ -3505,6 +3473,21 @@ vect_do_peeling (loop_vec_info loop_vinfo, tree niters, tree nitersm1,
if (LOOP_VINFO_EARLY_BREAKS (loop_vinfo))
iterate_fix_dominators (CDI_DOMINATORS, doms, false);
/* When we do not have a loop-around edge to the epilog we know
the vector loop covered at least VF scalar iterations unless
we have early breaks.
Update any known upper bound with this knowledge. */
if (! skip_vector
&& ! LOOP_VINFO_EARLY_BREAKS (loop_vinfo))
{
if (epilog->any_upper_bound)
epilog->nb_iterations_upper_bound -= lowest_vf;
if (epilog->any_likely_upper_bound)
epilog->nb_iterations_likely_upper_bound -= lowest_vf;
if (epilog->any_estimate)
epilog->nb_iterations_estimate -= lowest_vf;
}
unsigned HOST_WIDE_INT bound;
if (bound_scalar.is_constant (&bound))
{