[PATCH] vect: Verify that GET_MODE_NUNITS is greater than one.

[Michael Collison <collison@rivosinc.com>]

While working on autovectorizing for the RISCV port I encountered an issue
where can_duplicate_and_interleave_p assumes that GET_MODE_NUNITS is a
evenly divisible by two. The RISC-V target has vector modes (e.g. VNx1DImode),
where GET_MODE_NUNITS is equal to one.

Tested on RISCV and x86_64-linux-gnu. Okay?

2023-03-09  Michael Collison  <collison@rivosinc.com>

	* tree-vect-slp.cc (can_duplicate_and_interleave_p):
	Check that GET_MODE_NUNITS is greater than one.
---
 gcc/tree-vect-slp.cc | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/gcc/tree-vect-slp.cc b/gcc/tree-vect-slp.cc
index 9a4e000925e..add58113fa8 100644
--- a/gcc/tree-vect-slp.cc
+++ b/gcc/tree-vect-slp.cc
@@ -426,7 +426,8 @@ can_duplicate_and_interleave_p (vec_info *vinfo, unsigned int count,
 	  if (vector_type
 	      && VECTOR_MODE_P (TYPE_MODE (vector_type))
 	      && known_eq (GET_MODE_SIZE (TYPE_MODE (vector_type)),
-			   GET_MODE_SIZE (base_vector_mode)))
+			   GET_MODE_SIZE (base_vector_mode))
+	      && known_gt (GET_MODE_NUNITS (TYPE_MODE (vector_type)), 1))
 	    {
 	      /* Try fusing consecutive sequences of COUNT / NVECTORS elements
 		 together into elements of type INT_TYPE and using the result
-- 
2.34.1