This re-instantiates the previously removed CSE, fixing the
FAIL of gcc.dg/vect/costmodel/x86_64/costmodel-pr30843.c
It turns out the previous approach still works.
Bootstrapped and tested on x86_64-unknown-linux-gnu, pushed.
2020-11-04 Richard Biener <rguent...@suse.de>
* tree-vect-loop.c (vectorizable_induction): Re-instantiate
previously removed CSE of SLP IVs.
---
gcc/tree-vect-loop.c | 21 +++++++++++++++++++--
1 file changed, 19 insertions(+), 2 deletions(-)
diff --git a/gcc/tree-vect-loop.c b/gcc/tree-vect-loop.c
index 41e2e2ade20..c09aa392419 100644
--- a/gcc/tree-vect-loop.c
+++ b/gcc/tree-vect-loop.c
@@ -7874,8 +7874,16 @@ vectorizable_induction (loop_vec_info loop_vinfo,
if (nested_in_vect_loop)
nivs = nvects;
else
- nivs = least_common_multiple (group_size,
- const_nunits) / const_nunits;
+ {
+ /* Compute the number of distinct IVs we need. First reduce
+ group_size if it is a multiple of const_nunits so we get
+ one IV for a group_size of 4 but const_nunits 2. */
+ unsigned group_sizep = group_size;
+ if (group_sizep % const_nunits == 0)
+ group_sizep = group_sizep / const_nunits;
+ nivs = least_common_multiple (group_sizep,
+ const_nunits) / const_nunits;
+ }
tree stept = TREE_TYPE (step_vectype);
tree lupdate_mul = NULL_TREE;
if (!nested_in_vect_loop)
@@ -7975,6 +7983,15 @@ vectorizable_induction (loop_vec_info loop_vinfo,
SLP_TREE_VEC_STMTS (slp_node).quick_push (induction_phi);
}
+ if (!nested_in_vect_loop)
+ {
+ /* Fill up to the number of vectors we need for the whole group. */
+ nivs = least_common_multiple (group_size,
+ const_nunits) / const_nunits;
+ for (; ivn < nivs; ++ivn)
+ SLP_TREE_VEC_STMTS (slp_node)
+ .quick_push (SLP_TREE_VEC_STMTS (slp_node)[0]);
+ }
/* Re-use IVs when we can. We are generating further vector
stmts by adding VF' * stride to the IVs generated above. */
--
2.26.2
