https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96861
--- Comment #3 from Hongtao.liu <crazylht at gmail dot com> ---
(In reply to Hongtao.liu from comment #2)
> .
Difference comes from
/* Cost the integer to sse and sse to integer moves. */
cost += n_sse_to_integer * ix86_cost->sse_to_integer;
/* ??? integer_to_sse but we only have that in the RA cost table.
Assume sse_to_integer/integer_to_sse are the same which they
are at the moment. */
cost += n_integer_to_sse * ix86_cost->sse_to_integer;
Maybe need to increase ix86->sse_to_integer, i'm test the following.
--- a/gcc/config/i386/x86-tune-costs.h
+++ b/gcc/config/i386/x86-tune-costs.h
@@ -1769,7 +1769,7 @@ struct processor_costs skylake_cost = {
{6, 6, 6, 10, 20}, /* cost of unaligned loads. */
{8, 8, 8, 8, 16}, /* cost of unaligned stores. */
2, 2, 4, /* cost of moving XMM,YMM,ZMM register
*/
- 2, /* cost of moving SSE register to
integer. */
+ 6, /* cost of moving SSE register to
integer. */
20, 8, /* Gather load static, per_elt. */
22, 10, /* Gather store static, per_elt. */
64, /* size of l1 cache. */
