[ was: Re: [gomp4, nvptx, committed] Fix assert in nvptx_propagate_unified ]
On 07/06/2017 09:15 AM, Thomas Schwinge wrote:
Hi Tom!
On Fri, 30 Jun 2017 17:15:24 +0200, Tom de Vries <tom_devr...@mentor.com> wrote:
with the openacc test-case in attached patch, I ran into an assert here:
Using your test case, in my build with
"--enable-checking=yes,df,fold,rtl", I already earlier run into an ICE...
Hi,
I see, thanks for letting me know.
Hmm, it looks like the build and test config with which I ran into this
problem only has the default checking (All my private build and test
configs use yes,rtl).
static void
nvptx_propagate_unified (rtx_insn *unified)
{
rtx_insn *probe = unified;
rtx cond_reg = SET_DEST (PATTERN (unified));
rtx pat;
/* Find the comparison. (We could skip this and simply scan to he
blocks' terminating branch, if we didn't care for self
checking.) */
for (;;)
{
probe = NEXT_INSN (probe);
pat = PATTERN (probe);
... here:
[...]/libgomp/testsuite/libgomp.oacc-c/../libgomp.oacc-c-c++-common/reduction-cplx-flt-2.c:19:9:
internal compiler error: RTL check: expected elt 3 type 'e' or 'u', have '0'
(rtx note) in PATTERN, at rtl.h:1440
Breakpoint 2, internal_error (gmsgid=0x10cc840 "RTL check: expected elt %d type
'%c' or '%c', have '%c' (rtx %s) in %s, at %s:%d") at [...]/gcc/diagnostic.c:1251
1251 {
(gdb) bt
#0 internal_error (gmsgid=0x10cc840 "RTL check: expected elt %d type '%c' or
'%c', have '%c' (rtx %s) in %s, at %s:%d") at [...]/gcc/diagnostic.c:1251
#1 0x00000000009bd2c7 in rtl_check_failed_type2 (r=0x7ffff688cd40, n=<optimized out>, c1=<optimized out>,
c2=<optimized out>, file=<optimized out>, line=<optimized out>, func=0x106ac48
<_ZZ7PATTERNP7rtx_defE12__FUNCTION__> "PATTERN") at [...]/gcc/rtl.c:802
#2 0x0000000000529ef3 in PATTERN (insn=<optimized out>) at
[...]/gcc/rtl.h:1440
#3 0x00000000005e5a2b in PATTERN (insn=<optimized out>) at
[...]/gcc/rtl.h:1440
#4 0x0000000000d08b96 in nvptx_propagate_unified (unified=0x7ffff688ccc0)
at [...]/gcc/config/nvptx/nvptx.c:2299
#5 0x0000000000d093e7 in nvptx_split_blocks
(map=map@entry=0x7fffffffcc40) at [...]/gcc/config/nvptx/nvptx.c:2428
#6 0x0000000000d0d08b in nvptx_reorg () at
[...]/gcc/config/nvptx/nvptx.c:3840
#7 0x00000000009bb0ea in (anonymous namespace)::pass_machine_reorg::execute
(this=<optimized out>) at [...]/gcc/reorg.c:3952
[...]
(gdb) frame 4
#4 0x0000000000d08b96 in nvptx_propagate_unified (unified=0x7ffff688ccc0)
at [...]/gcc/config/nvptx/nvptx.c:2299
2299 pat = PATTERN (probe);
(gdb) print probe
$1 = (rtx_insn *) 0x7ffff688cd40
(gdb) call debug_rtx(probe)
(note 56 54 57 3 NOTE_INSN_DELETED)
if (GET_CODE (pat) == SET
&& GET_RTX_CLASS (GET_CODE (SET_SRC (pat))) == RTX_COMPARE
&& XEXP (SET_SRC (pat), 0) == cond_reg)
break;
gcc_assert (NONJUMP_INSN_P (probe));
}
...
The assert happens when processing insn 56:
...
(insn 54 53 56 3 (set (reg:SI 47 [ _71 ])
(unspec:SI [
(reg:SI 36 [ _58 ])
] UNSPEC_BR_UNIFIED)) 108 {cond_uni}
(nil))
(note 56 54 57 3 NOTE_INSN_DELETED)
(insn 57 56 58 3 (set (reg:BI 68)
(gt:BI (reg:SI 47 [ _71 ])
(const_int 1 [0x1]))) 99 {*cmpsi}
(expr_list:REG_DEAD (reg:SI 47 [ _71 ])
(nil)))
...
The insn 56 was originally a '(set (reg x) (const_int 1))', but that one
has been combined into insn 57 and replaced with a 'NOTE_INSN_DELETED'.
So it seems reasonable for the loop to skip over this note.
Fixed by making the assert condition less strict.
Build on x86_64 with nvptx accelerator.
Tested test-case included in the patch.
Committed as trivial.
--- a/gcc/config/nvptx/nvptx.c
+++ b/gcc/config/nvptx/nvptx.c
@@ -2300,7 +2300,7 @@ nvptx_propagate_unified (rtx_insn *unified)
&& GET_RTX_CLASS (GET_CODE (SET_SRC (pat))) == RTX_COMPARE
&& XEXP (SET_SRC (pat), 0) == cond_reg)
break;
- gcc_assert (NONJUMP_INSN_P (probe));
+ gcc_assert (NONJUMP_INSN_P (probe) || !INSN_P (probe));
}
rtx pred_reg = SET_DEST (pat);
These problems (both yours and mine) do not reproduce on trunk, right?
Correct, AFAICT nvptx_propagate_unified is something that was not ported
to trunk yet.
But I suppose these are still a latent, just waiting for a different test
case? Maybe this is a case to write an RTL-level test case? (Unless the
fix is deemed trivial enough to warrent spending time on this.)
Anyway, I don't know a lot about RTL, but the following patch does cure
this test case (now running other testing). Would you please check that,
and also whether nvptx_propagate_unified then still works as expected?
Is this patch OK (both for gomp-4_0-branch, and also for trunk?), or
should this rather use something like:
-if (!INSN_P (probe))
+if (NOTE_P (probe) && NOTE_KIND (probe) == NOTE_INSN_DELETED)
continue;
..., or something yet different?
I took most of your patch, but used next_real_insn to skip over the note.
Tested on x86_64 with nvptx accelerator.
Committed to gomp-4_0-branch.
Thanks,
- Tom
Fix --enable-checking=rtl assert in nvptx_propagate_unified
2017-07-16 Tom de Vries <t...@codesourcery.com>
* config/nvptx/nvptx.c (nvptx_propagate_unified): Use next_real_insn to
find comparison insn. Assert that comparison is found.
---
gcc/config/nvptx/nvptx.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/gcc/config/nvptx/nvptx.c b/gcc/config/nvptx/nvptx.c
index 69b5740..32420c3 100644
--- a/gcc/config/nvptx/nvptx.c
+++ b/gcc/config/nvptx/nvptx.c
@@ -2294,22 +2294,25 @@ nvptx_propagate_unified (rtx_insn *unified)
{
rtx_insn *probe = unified;
rtx cond_reg = SET_DEST (PATTERN (unified));
- rtx pat;
+ rtx pat = NULL_RTX;
/* Find the comparison. (We could skip this and simply scan to he
blocks' terminating branch, if we didn't care for self
checking.) */
for (;;)
{
- probe = NEXT_INSN (probe);
+ probe = next_real_insn (probe);
+ if (!probe)
+ break;
pat = PATTERN (probe);
if (GET_CODE (pat) == SET
&& GET_RTX_CLASS (GET_CODE (SET_SRC (pat))) == RTX_COMPARE
&& XEXP (SET_SRC (pat), 0) == cond_reg)
break;
- gcc_assert (NONJUMP_INSN_P (probe) || !INSN_P (probe));
+ gcc_assert (NONJUMP_INSN_P (probe));
}
+ gcc_assert (pat);
rtx pred_reg = SET_DEST (pat);
/* Find the branch. */
