The validation phase of vectorizable_shift used TYPE_MODE to check
whether the shift amount vector was compatible with the shifted vector:
if ((op1_vectype == NULL_TREE
|| TYPE_MODE (op1_vectype) != TYPE_MODE (vectype))
&& (!slp_node
|| SLP_TREE_DEF_TYPE
(SLP_TREE_CHILDREN (slp_node)[1]) != vect_constant_def))
But the generation phase was stricter and required the element types to
be equivalent:
&& !useless_type_conversion_p (TREE_TYPE (vectype),
TREE_TYPE (op1)))
This difference led to an ICE with a later patch.
The first condition seems a bit too lax given that the function
supports vect_worthwhile_without_simd_p, where two different vector
types could have the same integer mode. But it seems too strict
to reject signed shifts by unsigned amounts or unsigned shifts by
signed amounts; verify_gimple_assign_binary is happy with those.
This patch therefore goes for a middle ground of checking both TYPE_MODE
and TYPE_VECTOR_SUBPARTS, using the same condition in both places.
2019-10-24 Richard Sandiford <richard.sandif...@arm.com>
gcc/
* tree-vect-stmts.c (vectorizable_shift): Check the number
of vector elements as well as the type mode when deciding
whether an op1_vectype is compatible. Reuse the result of
this check when generating vector statements.
Index: gcc/tree-vect-stmts.c
===================================================================
--- gcc/tree-vect-stmts.c 2019-10-25 13:27:08.653811531 +0100
+++ gcc/tree-vect-stmts.c 2019-10-25 13:27:12.121787027 +0100
@@ -5522,6 +5522,7 @@ vectorizable_shift (stmt_vec_info stmt_i
bool scalar_shift_arg = true;
bb_vec_info bb_vinfo = STMT_VINFO_BB_VINFO (stmt_info);
vec_info *vinfo = stmt_info->vinfo;
+ bool incompatible_op1_vectype_p = false;
if (!STMT_VINFO_RELEVANT_P (stmt_info) && !bb_vinfo)
return false;
@@ -5666,8 +5667,12 @@ vectorizable_shift (stmt_vec_info stmt_i
if (!op1_vectype)
op1_vectype = get_same_sized_vectype (TREE_TYPE (op1), vectype_out);
- if ((op1_vectype == NULL_TREE
- || TYPE_MODE (op1_vectype) != TYPE_MODE (vectype))
+ incompatible_op1_vectype_p
+ = (op1_vectype == NULL_TREE
+ || maybe_ne (TYPE_VECTOR_SUBPARTS (op1_vectype),
+ TYPE_VECTOR_SUBPARTS (vectype))
+ || TYPE_MODE (op1_vectype) != TYPE_MODE (vectype));
+ if (incompatible_op1_vectype_p
&& (!slp_node
|| SLP_TREE_DEF_TYPE
(SLP_TREE_CHILDREN (slp_node)[1]) != vect_constant_def))
@@ -5813,9 +5818,7 @@ vectorizable_shift (stmt_vec_info stmt_i
}
}
}
- else if (slp_node
- && !useless_type_conversion_p (TREE_TYPE (vectype),
- TREE_TYPE (op1)))
+ else if (slp_node && incompatible_op1_vectype_p)
{
if (was_scalar_shift_arg)
{
