This patch makes vectorizable_conversion cope with variable-length
vectors. We already require the number of elements in one vector
to be a multiple of the number of elements in the other vector,
so the patch uses that to choose between widening and narrowing.
2017-10-23 Richard Sandiford <richard.sandif...@linaro.org>
Alan Hayward <alan.hayw...@arm.com>
David Sherwood <david.sherw...@arm.com>
gcc/
* tree-vect-stmts.c (vectorizable_conversion): Treat the number
of units as polynomial. Choose between WIDE and NARROW based
on multiple_p.
Index: gcc/tree-vect-stmts.c
===================================================================
--- gcc/tree-vect-stmts.c 2017-10-23 17:22:40.906378704 +0100
+++ gcc/tree-vect-stmts.c 2017-10-23 17:22:41.879277786 +0100
@@ -4102,8 +4102,8 @@ vectorizable_conversion (gimple *stmt, g
int ndts = 2;
gimple *new_stmt = NULL;
stmt_vec_info prev_stmt_info;
- int nunits_in;
- int nunits_out;
+ poly_uint64 nunits_in;
+ poly_uint64 nunits_out;
tree vectype_out, vectype_in;
int ncopies, i, j;
tree lhs_type, rhs_type;
@@ -4238,12 +4238,15 @@ vectorizable_conversion (gimple *stmt, g
nunits_in = TYPE_VECTOR_SUBPARTS (vectype_in);
nunits_out = TYPE_VECTOR_SUBPARTS (vectype_out);
- if (nunits_in < nunits_out)
- modifier = NARROW;
- else if (nunits_out == nunits_in)
+ if (must_eq (nunits_out, nunits_in))
modifier = NONE;
+ else if (multiple_p (nunits_out, nunits_in))
+ modifier = NARROW;
else
- modifier = WIDEN;
+ {
+ gcc_checking_assert (multiple_p (nunits_in, nunits_out));
+ modifier = WIDEN;
+ }
/* Multiple types in SLP are handled by creating the appropriate number of
vectorized stmts for each SLP node. Hence, NCOPIES is always 1 in
