[Bug tree-optimization/32575] [4.2/4.3 regression] With -ftree-vrp miscompiles a single line of code in SQLite

[jakub at gcc dot gnu dot org]

--- Comment #17 from jakub at gcc dot gnu dot org  2007-11-08 13:08 ---
Subject: Bug 32575

Author: jakub
Date: Thu Nov  8 13:07:54 2007
New Revision: 129998

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=129998
Log:
PR tree-optimization/32575
* gcc.c-torture/execute/20071108-1.c: New test.

Added:
trunk/gcc/testsuite/gcc.c-torture/execute/20071108-1.c
Modified:
trunk/gcc/testsuite/ChangeLog


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32575

[Bug tree-optimization/32575] [4.2/4.3 regression] With -ftree-vrp miscompiles a single line of code in SQLite

[jakub at gcc dot gnu dot org]

--- Comment #16 from jakub at gcc dot gnu dot org  2007-11-08 12:54 ---
Continuing after the #c11 .. #c15 unrelated PR32540 comments with the original
bug:

I've built -r127926 and -r127927 cc1 and it seems this wasn't fixed just by
a side-effect.
Although p can be either retval of foo or &q, we had in 127926:
  # pD.2027_1 = PHI 
  # qD.2028_18 = VDEF  { qD.2028 }
  pD.2027_1->s1D.2010 = aD.2023_6(D);
while 127927 has:
  # pD.2027_1 = PHI 
  # qD.2028_19 = VDEF 
  # SMT.26D.2082_20 = VDEF  { qD.2028 SMT.26D.2082 }
  pD.2027_1->s1D.2010 = aD.2023_6(D);

-pD.2027_1, name memory tag: NMT.27D.2083, is dereferenced, points-to vars: { q
}
+pD.2027_1, name memory tag: NMT.27D.2083, is dereferenced, points-to vars: { q
SMT.26 }

So guess I'll just submit the testcase for inclusion on the trunk and then we
can close this PR.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32575

[Bug tree-optimization/32575] [4.2/4.3 regression] With -ftree-vrp miscompiles a single line of code in SQLite

[rguenth at gcc dot gnu dot org]

--- Comment #15 from rguenth at gcc dot gnu dot org  2007-11-01 15:05 
---
Indeed it does.  But while this is a workaround that works, the problem is in
excessive phi translation which we could stop here (untested! just a wild
guess!):

static bool
compute_partial_antic_aux (basic_block block,
   bool block_has_abnormal_pred_edge)
{
...
  if (phi_nodes (bprime))
{

and limit the # of PHI args seen here instead?


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32575

[Bug tree-optimization/32575] [4.2/4.3 regression] With -ftree-vrp miscompiles a single line of code in SQLite

[nickc at redhat dot com]

--- Comment #14 from nickc at redhat dot com  2007-11-01 14:57 ---
Subject: Re:  [4.2/4.3 regression] With -ftree-vrp
 miscompiles a single line of code in SQLite

Hi Jakub,

> Nick, your patch is most probably fixing PR32540 rather than PR32575, doesn't
> it?

Doh.  Yes.  I will fix that in my local sources so that if the patch is 
approved the correct number is used.

Cheers
   Nick


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32575

[Bug tree-optimization/32575] [4.2/4.3 regression] With -ftree-vrp miscompiles a single line of code in SQLite

[jakub at gcc dot gnu dot org]

--- Comment #13 from jakub at gcc dot gnu dot org  2007-11-01 14:34 ---
Nick, your patch is most probably fixing PR32540 rather than PR32575, doesn't
it?


-- 

jakub at gcc dot gnu dot org changed:

   What|Removed |Added

 CC||nickc at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32575

[Bug tree-optimization/32575] [4.2/4.3 regression] With -ftree-vrp miscompiles a single line of code in SQLite

[nickc at redhat dot com]

--- Comment #12 from nickc at redhat dot com  2007-11-01 14:05 ---
Hi Guys,

  I have uploaded a patch for a possible workaround for this problem.  It adds
a new param (max-partial-antic-length) which with its default value will stop
the tree-pre optimization from eating up all the memory on the host system.  It
also adds a testcase for the PR and documents the new param.  Tested without
regressions on an x86_64-linux-gnu toolchain.

  What do you think, should this patch be applied ?

Cheers
  Nick


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32575

[Bug tree-optimization/32575] [4.2/4.3 regression] With -ftree-vrp miscompiles a single line of code in SQLite

[nickc at redhat dot com]

--- Comment #11 from nickc at redhat dot com  2007-11-01 14:02 ---
Created an attachment (id=14451)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=14451&action=view)
Add a param to squelch runaway memory consumption


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32575

[Bug tree-optimization/32575] [4.2/4.3 regression] With -ftree-vrp miscompiles a single line of code in SQLite

[mmitchel at gcc dot gnu dot org]

--- Comment #10 from mmitchel at gcc dot gnu dot org  2007-10-09 19:20 
---
Change target milestone to 4.2.3, as 4.2.2 has been released.


-- 

mmitchel at gcc dot gnu dot org changed:

   What|Removed |Added

   Target Milestone|4.2.2   |4.2.3


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32575

[Bug tree-optimization/32575] [4.2/4.3 regression] With -ftree-vrp miscompiles a single line of code in SQLite

[jakub at gcc dot gnu dot org]

--- Comment #9 from jakub at gcc dot gnu dot org  2007-09-10 18:38 ---
Fails e.g. with 127816, 127870 up to 127926, the bug goes away
at least on the #c5 testcase with
http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=127927


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32575