On Dec 20, 2017, Alexandre Oliva <aol...@redhat.com> wrote:
> things work reasonably flawlessly now is not suggestive that it was
> easy, or not too intrusive, but rather that the work to make it seamless
> despite the intrusiveness was done, at first, and then over time.
> That's the reason for -fcompare-debug and the various bootstrap options
> that stress it further.
> sparc64-linux-gnu ran into -fcompare-debug failures early in stage3,
> the same I ran into before, and that I'll investigate next.
The problems I observed on sparc64 were all similar, caused by the
delayed branch infrastructure. Here's a patch that fixes it. Testing
on sparc64-linux-gnu underway, but I'm posting it right away because
it's so obvious. And yet, I ask: ok to install?
This fixes stage3 -fcompare-debug builds of at least the builds of
libbacktrace/dwarf.o, zlib/deflate.o, and libiberty/cplus-dem.o.
[-fcompare-debug] retain insn locations when turning dbr seq into return
A number of -fcompare-debug errors on sparc arise as we split a dbr
SEQUENCE back into separate insns to turn the branch into a return.
If we just take the location from the PREV_INSN, it might be a debug
insn without INSN_LOCATION, or an insn with an unrelated location.
But that's silly: each of the SEQUENCEd insns is still an insn with
its own INSN_LOCATION, so use that instead, even though some may have
been adjusted while constructing the SEQUENCE.
for gcc/ChangeLog
* reorg.c (make_return_insns): Reemit each insn with its own
location.
---
gcc/reorg.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/gcc/reorg.c b/gcc/reorg.c
index 96778addce52..02d8adc61808 100644
--- a/gcc/reorg.c
+++ b/gcc/reorg.c
@@ -3612,9 +3612,14 @@ make_return_insns (rtx_insn *first)
delete_related_insns (insn);
for (i = 1; i < XVECLEN (pat, 0); i++)
- prev = emit_insn_after (PATTERN (XVECEXP (pat, 0, i)), prev);
+ {
+ rtx_insn *in_seq_insn = as_a<rtx_insn *> (XVECEXP (pat, 0, i));
+ prev = emit_insn_after_setloc (PATTERN (in_seq_insn), prev,
+ INSN_LOCATION (in_seq_insn));
+ }
- insn = emit_jump_insn_after (PATTERN (jump_insn), prev);
+ insn = emit_jump_insn_after_setloc (PATTERN (jump_insn), prev,
+ INSN_LOCATION (jump_insn));
emit_barrier_after (insn);
if (slots)
--
Alexandre Oliva, freedom fighter http://FSFLA.org/~lxoliva/
You must be the change you wish to see in the world. -- Gandhi
Be Free! -- http://FSFLA.org/ FSF Latin America board member
Free Software Evangelist|Red Hat Brasil GNU Toolchain Engineer
