On 17/11/15 16:18, Richard Biener wrote:
IMHO autopar needs to handle induction itself.
>
>I'm not sure what you mean. Could you elaborate? Autopar handles induction
>variables, but it doesn't handle exit phis reading the final value of the
>induction variable. Is that what you want fixed? How?
Yes. Perform final value replacement.
I see. Calling scev_const_prop in pass_parallelize_loops_oacc_kernels
seems to work fine.
Doing the same for pass_parallelize_loops like this:
...
diff --git a/gcc/tree-parloops.c b/gcc/tree-parloops.c
index 17415a8..d944395 100644
--- a/gcc/tree-parloops.c
+++ b/gcc/tree-parloops.c
@@ -2787,6 +2787,9 @@ pass_parallelize_loops::execute (function *fun)
if (number_of_loops (fun) <= 1)
return 0;
+ unsigned int sccp_todo = scev_const_prop ();
+ gcc_assert (sccp_todo == 0);
+
if (parallelize_loops ())
{
fun->curr_properties &= ~(PROP_gimple_eomp);
...
seems to fix PR 68373 - "autopar fails on loop exit phi with argument
defined outside loop".
The new scev_const_prop call in autopar rewrites this phi into an
assignment, and that allows parloops to succeed:
...
final value replacement:
n_2 = PHI <n_4(D)(4)>
with
n_2 = n_4(D);
...
Thanks,
- Tom
