diff mbox

[gomp4,nvptx,committed] Fix --enable-checking=rtl assert in nvptx_propagate_unified

Message ID 1c63678b-8d00-febb-a494-84dfb206bcdd@mentor.com
State New
Headers show

Commit Message

Tom de Vries July 16, 2017, 6:59 p.m. UTC 
[ 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_deVries@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
diff mbox

Patch

Fix --enable-checking=rtl assert in nvptx_propagate_unified

2017-07-16  Tom de Vries  <tom@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.  */