On Wed, Jan 08, 2014 at 05:54:55PM +0100, Uros Bizjak wrote:
This caused PR59724 on alpha:
20021116-1.c: In function âfooâ:
20021116-1.c:31:1: error: NOTE_INSN_BASIC_BLOCK is missing for block 9
}
^
20021116-1.c:31:1: error: insn outside basic block
(jump_insn 94 52 93 9 (return) 20021116-1.c:31 -1
(nil)
-> return)
Ugh, indeed. The problem is that try_head_merge_bb really wants
flow_find_head_matching_sequence to count all (non-note) insns, not
just active insns, because otherwise as in the above testcase we
can have e.g. 2 active insns followed by one non-active, all matching
(flow_find_head_matching_sequence returns 2) and on another edge
just 2 active insns and nothing else matching. 2 == 2, so the caller
thinks it doesn't matter which one is shorter, but we have the insn range
of 3 insns together.
So, this patch just reverts the try_head_merge_bb changes and makes
flow_find_head_matching_sequence behave the old way when called from
try_head_merge_bb, i.e. count all non-note insns, and only when called
from ifcvt.c count just active insns. Plus the ifcvt.c change ensures
we don't mistakenly call it with stop_after == 0 (which wouldn't actually
stop).
Bootstrapped/regtested on x86_64-linux and i686-linux, Uros is testing it
on Alpha. Ok for trunk?
2014-01-08 Jakub Jelinek <jakub@redhat.com>
PR rtl-optimization/59724
* ifcvt.c (cond_exec_process_if_block): Don't call
flow_find_head_matching_sequence with 0 longest_match.
* cfgcleanup.c (flow_find_head_matching_sequence): Count even
non-active insns if !stop_after.
(try_head_merge_bb): Revert 2014-01-07 changes.