Richard,
I have a tentative fix for PR50764.
In the example from the test-case, -fsched2-use-superblocks moves an insn from
block 4 to block 3.
2
bar
|
-------+-----
/ \
* *
5 *------------ 3
abort bar
|
|
*
4
return
The insn has a REG_CFA_DEF_CFA note and is frame-related.
...
(insn/f 51 50 52 4 (set (reg:DI 39 r10)
(mem/c:DI (plus:DI (reg/f:DI 6 bp)
(const_int -8 [0xfffffffffffffff8])) [3 S8 A8])) pr50764.c:13
62 {*movdi_internal_rex64}
(expr_list:REG_CFA_DEF_CFA (reg:DI 39 r10)
(nil)))
...
This causes the assert in maybe_record_trace_start to trigger:
...
/* We ought to have the same state incoming to a given trace no
matter how we arrive at the trace. Anything else means we've
got some kind of optimization error. */
gcc_checking_assert (cfi_row_equal_p (cur_row, ti->beg_row));
...
The assert does not occur with -fno-tree-tail-merge, but that is due to the
following:
- -fsched-use-superblocks does not handle dead labels explicitly
- -freorder-blocks introduces a dead label, which is not removed until after
sched2
- -ftree-tail-merge makes a difference in which block -freorder-blocks
introduces the dead label. In the case of -ftree-tail-merge, the dead label
is introduced at the start of block 3, and block 3 and 4 end up in the same
ebb. In the case of -fno-tree-tail-merge, the dead label is introduced at the
start of block 4, and block 3 and 4 don't end up in the same ebb.
attached untested patch fixes PR50764 in a similar way as the patch for PR49994,
which is also about an ICE in maybe_record_trace_start with
-fsched2-use-superblocks.
The patch for PR49994 makes sure frame-related instructions are not moved past
the following jump.
Attached patch makes sure frame-related instructions are not moved past the
preceding jump.
Is this the way to fix this PR?
Thanks,
- Tom
2011-10-29 Tom de Vries <t...@codesourcery.com>
PR rtl-optimization/50764
* (sched_analyze_insn): Make sure frame-related insns are not moved past
preceding jump.
Index: gcc/sched-deps.c
===================================================================
--- gcc/sched-deps.c (revision 180521)
+++ gcc/sched-deps.c (working copy)
@@ -2812,8 +2812,13 @@ sched_analyze_insn (struct deps_desc *de
during prologue generation and avoid marking the frame pointer setup
as frame-related at all. */
if (RTX_FRAME_RELATED_P (insn))
- deps->sched_before_next_jump
- = alloc_INSN_LIST (insn, deps->sched_before_next_jump);
+ {
+ deps->sched_before_next_jump
+ = alloc_INSN_LIST (insn, deps->sched_before_next_jump);
+
+ if (deps->pending_jump_insns)
+ add_dependence (insn, XEXP (deps->pending_jump_insns, 0), REG_DEP_ANTI);
+ }
if (code == COND_EXEC)
{
