On 01/30/2018 11:11 AM, Jakub Jelinek wrote:
Hi!
We don't want to move /f instructions across jumps in either direction,
sched_analyze_insn has code for that by adding the insn into
sched_before_next_jump list and by adding anti dependence against
pending_jump_insns. That works fine, as long as we don't flush the
dependency lists, flush_pending_lists will flush them and just add the
insn that was flushed into last_pending_memory_flush.
Yes, we don't think to move frame related insns. As most frame insns
are moves of args from hard regs to pseudos it might result in troubles
in LRA can not find a spill regs because it has limited possibilities to
spill hard regs. RA actually will try to remove these moves by
assigning the same hard regs to the pseudos so scheduling them has a
little sense.
For frame related insns, we are looking solely for deps->pending_jump_insns
and thus if we've flushed, we miss anti dependency against insn that has
anti dependencies against jumps.
The following patch fixes it by also adding an anti dependency against
last_pending_memory_flush insn if any.
Bootstrapped on {x86_64,i686,powerpc64le,powerpc64}-linux and regtested
on the first 3, with powerpc64-linux regtest -m32/-m64 still pending,
ok for trunk if it passes even there?
OK. Thanks, Jakub.
2018-01-30 Jakub Jelinek <ja...@redhat.com>
PR rtl-optimization/83986
* sched-deps.c (sched_analyze_insn): For frame related insns, add anti
dependence against last_pending_memory_flush in addition to
pending_jump_insns.
* gcc.dg/pr83986.c: New test.
--- gcc/sched-deps.c.jj 2018-01-27 07:27:51.723937094 +0100
+++ gcc/sched-deps.c 2018-01-30 13:09:16.891173722 +0100
@@ -2922,6 +2922,8 @@ sched_analyze_insn (struct deps_desc *de
= alloc_INSN_LIST (insn, deps->sched_before_next_jump);
/* Make sure epilogue insn is scheduled after preceding jumps. */
+ add_dependence_list (insn, deps->last_pending_memory_flush, 1,
+ REG_DEP_ANTI, true);
add_dependence_list (insn, deps->pending_jump_insns, 1, REG_DEP_ANTI,
true);
}
--- gcc/testsuite/gcc.dg/pr83986.c.jj 2018-01-30 13:34:13.254828800 +0100
+++ gcc/testsuite/gcc.dg/pr83986.c 2018-01-30 13:33:55.973832214 +0100
@@ -0,0 +1,14 @@
+/* PR rtl-optimization/83986 */
+/* { dg-do compile } */
+/* { dg-options "-g -O2 -fsched2-use-superblocks -funwind-tables --param
max-pending-list-length=1" } */
+
+int v;
+
+int
+foo (int x)
+{
+ v &= !!v && !!x;
+ if (v != 0)
+ foo (0);
+ return 0;
+}
Jakub
