[Bug tree-optimization/67830] [6 Regression] wrong code at -O1 and above on x86_64-linux-gnu

[law at redhat dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67830

Jeffrey A. Law  changed:

   What|Removed |Added

 Status|NEW |RESOLVED
 Resolution|--- |FIXED

--- Comment #7 from Jeffrey A. Law  ---
Fixed on the trunk.

[Bug tree-optimization/67830] [6 Regression] wrong code at -O1 and above on x86_64-linux-gnu

[law at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67830

--- Comment #6 from Jeffrey A. Law  ---
Author: law
Date: Fri Oct 23 19:16:53 2015
New Revision: 229267

URL: https://gcc.gnu.org/viewcvs?rev=229267=gcc=rev
Log:
[RFA] Fix pr67830, another type narrowing problem

PR tree-optimization/67830
* match.pd ((bit_and (plus/minus (convert @0) (convert @1)) mask)):
Explicitly verify the mask has no bits outside the type of
the innermost operands.

PR tree-optimization/67830
* gcc.dg/pr67830.c: New test.

Added:
trunk/gcc/testsuite/gcc.dg/pr67830.c
Modified:
trunk/gcc/ChangeLog
trunk/gcc/match.pd
trunk/gcc/testsuite/ChangeLog

[Bug tree-optimization/67830] [6 Regression] wrong code at -O1 and above on x86_64-linux-gnu

[law at redhat dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67830

--- Comment #5 from Jeffrey A. Law  ---
Whoops.  c#4 was for an unrelated BZ.

[Bug tree-optimization/67830] [6 Regression] wrong code at -O1 and above on x86_64-linux-gnu

[law at redhat dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67830

Jeffrey A. Law  changed:

   What|Removed |Added

 CC||law at redhat dot com

--- Comment #4 from Jeffrey A. Law  ---
The discrepancy between the release checking and development build is the
ENABLE_GC_CHECKING is not enabled in the former, but is enabled in the latter.

We're looking at a gc_free'd blob of memory in the threader due to a case which
I initially didn't think could happen because of some oddities in the FSM bits
that I'd forgotten about.

I'm pondering the best way forward.

[Bug tree-optimization/67830] [6 Regression] wrong code at -O1 and above on x86_64-linux-gnu

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67830

Richard Biener  changed:

   What|Removed |Added

 Status|UNCONFIRMED |ASSIGNED
   Last reconfirmed||2015-10-05
  Component|rtl-optimization|tree-optimization
   Target Milestone|--- |6.0
Summary|wrong code at -O1 and above |[6 Regression] wrong code
   |on x86_64-linux-gnu |at -O1 and above on
   ||x86_64-linux-gnu
 Ever confirmed|0   |1

--- Comment #1 from Richard Biener  ---
Confirmed.  .optimized already has an unconditional abort() call and forwprop2
changes it to that.

Applying pattern match.pd:2322, gimple-match.c:2002
gimple_simplified to _15 = d.2_9 - _5;
_16 = _15 & 254;
_12 = (int) _16;
Applying pattern match.pd:1853, generic-match.c:5128
  Replaced '_12 != -2' with '1'
gimple_simplified to if (1 != 0)

[Bug tree-optimization/67830] [6 Regression] wrong code at -O1 and above on x86_64-linux-gnu

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67830

Richard Biener  changed:

   What|Removed |Added

 Status|ASSIGNED|NEW
 CC||law at gcc dot gnu.org

--- Comment #2 from Richard Biener  ---
  _7 = (int) _5;
  _10 = (int) d.2_9;
  f_11 = _10 - _7;
  _12 = f_11 & -2;

with _5 and d.2_9 being of type unsigned char is transformed to

  _15 = d.2_9 - _5;
  _16 = _15 & 254;
  _12 = (int) _16;

with _16 being unsigned char.  That looks wrong as it changes a
sign-extended subtraction result to a zero-extended one.

CCing Jeff who added that pattern.

[Bug tree-optimization/67830] [6 Regression] wrong code at -O1 and above on x86_64-linux-gnu

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67830

Marek Polacek  changed:

   What|Removed |Added

 CC||mpolacek at gcc dot gnu.org

--- Comment #3 from Marek Polacek  ---
Started with r222877.