As PR105940 shown, when rs6000 port tries to assign
m_suggested_unroll_factor by 4 or so, there will be ICE on:
exact_div (LOOP_VINFO_VECT_FACTOR (loop_vinfo),
loop_vinfo->suggested_unroll_factor);
In function vect_analyze_loop_2, the current place of
suggested_unroll_factor applying can't guarantee it's
applied for all cases. As the case shows, vectorizer
could retry with SLP forced off, the vf is reset by
saved_vectorization_factor which isn't applied with
suggested_unroll_factor before. It means it can end
up with one vf which neglects suggested_unroll_factor.
I think it's off design, we should move the applying
of suggested_unroll_factor after start_over.
PR tree-optimization/105940
gcc/ChangeLog:
* tree-vect-loop.cc (vect_analyze_loop_2): Move the place of
applying suggested_unroll_factor after start_over.
set of rgroups. */
gcc_assert (LOOP_VINFO_MASKS (loop_vinfo).is_empty ());
+ /* This is the point where we can re-start analysis with SLP forced off. */
+start_over:
+
/* Apply the suggested unrolling factor, this was determined by the backend
during finish_cost the first time we ran the analyzis for this
vector mode. */
if (loop_vinfo->suggested_unroll_factor > 1)
LOOP_VINFO_VECT_FACTOR (loop_vinfo) *= loop_vinfo->suggested_unroll_factor;
- /* This is the point where we can re-start analysis with SLP forced off. */
-start_over:
-
/* Now the vectorization factor is final. */
poly_uint64 vectorization_factor = LOOP_VINFO_VECT_FACTOR (loop_vinfo);
gcc_assert (known_ne (vectorization_factor, 0U));