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| author | Richard Biener <rguenther@suse.de> | 2024-08-30 09:50:32 +0200 |
|---|---|---|
| committer | Richard Biener <rguenth@gcc.gnu.org> | 2024-08-30 12:47:12 +0200 |
| commit | d48273f06fee3886b05ce4d10b4db3d52f1991dc (patch) | |
| tree | 63feb441b5c558735234a0a33206539b567b8da9 | |
| parent | e7c7397236544f0e7dbb1ffa635b58126157dc86 (diff) | |
| download | gcc-d48273f06fee3886b05ce4d10b4db3d52f1991dc.zip gcc-d48273f06fee3886b05ce4d10b4db3d52f1991dc.tar.gz gcc-d48273f06fee3886b05ce4d10b4db3d52f1991dc.tar.bz2 | |
Avoid division by zero via constant_multiple_p
With recent SLP vectorization patches I see RISC-V divison by zero
for gfortran.dg/matmul_10.f90 and others in get_group_load_store_type
which does
&& can_div_trunc_p (group_size
* LOOP_VINFO_VECT_FACTOR (loop_vinfo) - gap,
nunits, &tem, &remain)
&& (known_eq (remain, 0u)
|| (constant_multiple_p (nunits, remain, &num)
&& (vector_vector_composition_type (vectype, num,
&half_vtype)
!= NULL_TREE))))
overrun_p = false;
where for [2, 2] / [0, 2] the condition doesn't reflect what we
are trying to test - that, when remain is zero or, when non-zero,
nunits is a multiple of remain, we can avoid touching a gap via
loading smaller pieces and vector composition.
It isn't safe to change the known_eq to maybe_eq so instead
require known_ne (remain, 0u) before doing constant_multiple_p.
There's the corresponding code in vectorizable_load that's known
to have a latent similar issue, so sync that up as well.
* tree-vect-stmts.cc (get_group_load_store_type): Check
known_ne (remain, 0u) before doing constant_multiple_p.
(vectorizable_load): Likewise.
| -rw-r--r-- | gcc/tree-vect-stmts.cc | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/gcc/tree-vect-stmts.cc b/gcc/tree-vect-stmts.cc index 03c65f0..72a29c0 100644 --- a/gcc/tree-vect-stmts.cc +++ b/gcc/tree-vect-stmts.cc @@ -2126,7 +2126,8 @@ get_group_load_store_type (vec_info *vinfo, stmt_vec_info stmt_info, * LOOP_VINFO_VECT_FACTOR (loop_vinfo) - gap, nunits, &tem, &remain) && (known_eq (remain, 0u) - || (constant_multiple_p (nunits, remain, &num) + || (known_ne (remain, 0u) + && constant_multiple_p (nunits, remain, &num) && (vector_vector_composition_type (vectype, num, &half_vtype) != NULL_TREE)))) @@ -11519,7 +11520,8 @@ vectorizable_load (vec_info *vinfo, { /* remain should now be > 0 and < nunits. */ unsigned num; - if (constant_multiple_p (nunits, remain, &num)) + if (known_ne (remain, 0u) + && constant_multiple_p (nunits, remain, &num)) { tree ptype; new_vtype |