Hi!
On a testcase which has 100000 consecutive debug insns sched2 spends
a lot of time calling prev_nonnote_nondebug_insn on each of the debug
insns, even when it is completely useless, because no target wants
to fuse a non-debug insn with some debug insn after it, it makes sense
only for two non-debug insns.
By returning early for those, we'll just walk the long set of them once when
we process some non-debug instruction after a long block of debug insns.
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
2018-01-26 Jakub Jelinek <ja...@redhat.com>
PR middle-end/84040
* sched-deps.c (sched_macro_fuse_insns): Return immediately for
debug insns.
--- gcc/sched-deps.c.jj 2018-01-03 10:19:56.301534141 +0100
+++ gcc/sched-deps.c 2018-01-26 16:21:01.922414579 +0100
@@ -2834,10 +2834,16 @@ static void
sched_macro_fuse_insns (rtx_insn *insn)
{
rtx_insn *prev;
+ /* No target hook would return true for debug insn as any of the
+ hook operand, and with very large sequences of only debug insns
+ where on each we call sched_macro_fuse_insns it has quadratic
+ compile time complexity. */
+ if (DEBUG_INSN_P (insn))
+ return;
prev = prev_nonnote_nondebug_insn (insn);
if (!prev)
return;
-
+
if (any_condjump_p (insn))
{
unsigned int condreg1, condreg2;
Jakub
