[Bug rtl-optimization/67344] New: PowerPC unrecognizable insn

[Bug rtl-optimization/67344] New: PowerPC unrecognizable insn

[anton at samba dot org]

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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67344

            Bug ID: 67344
           Summary: PowerPC unrecognizable insn
           Product: gcc
           Version: 5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: rtl-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: anton at samba dot org
  Target Milestone: ---

The following testcase:

# cat testcase.c

int a, b, c;
void fn2(void);

int fn1(char p1)
{
        short d;
        for (;;)
                for (; c <= 3;) {
                        fn2();
                        d = p1 / 2;
                        b = d & 11 && a;
                }
}

hits an ICE:

# gcc -O1 -c testcase.i

testcase2.i: In function ‘fn1’:
testcase2.i:13:1: error: unrecognizable insn:
 }
 ^
(insn 74 4 75 2 (set (reg:DI 9 9)
        (and:DI (lshiftrt:DI (reg:DI 3 3 [ p1 ])
                (const_int 1 [0x1]))
            (const_int 11 [0xb]))) testcase2.i:11 -1
     (nil))
testcase2.i:13:1: internal compiler error: in extract_insn, at recog.c:2297
0x107923e3 _fatal_insn(char const*, rtx_def const*, char const*, int, char
const*)
        ../../gcc/gcc/rtl-error.c:109
0x1079245f _fatal_insn_not_found(rtx_def const*, char const*, int, char const*)
        ../../gcc/gcc/rtl-error.c:117
0x10755a87 extract_insn(rtx_insn*)
        ../../gcc/gcc/recog.c:2297
0x10755b4f extract_insn_cached(rtx_insn*)
        ../../gcc/gcc/recog.c:2188
0x1049f37b cleanup_subreg_operands(rtx_insn*)
        ../../gcc/gcc/final.c:3112
0x10751dd7 split_insn
        ../../gcc/gcc/recog.c:2910
0x10758d77 split_all_insns()
        ../../gcc/gcc/recog.c:2964
0x10758eab rest_of_handle_split_after_reload
        ../../gcc/gcc/recog.c:3904
0x10758eab execute
        ../../gcc/gcc/recog.c:3933
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From: "EisahLee at gmx dot de" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c++/67345] New: -Woverloaded-virtual false negative: Does not warn on overloaded virtual function
Date: Mon, 24 Aug 2015 23:10:00 -0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?idg345

            Bug ID: 67345
           Summary: -Woverloaded-virtual false negative: Does not warn on
                    overloaded virtual function
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: major
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: EisahLee at gmx dot de
  Target Milestone: ---

Created attachment 36251
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id6251&actioníit
Example program to demonstrate missing warning.

See example program in attachment.

Crucial steps to reproduce code that exhibits the bug:
'MyDerived' defines 'virtual frob(int, int)', and hides the non-virtual
'frob(int)' of 'MyBase'.

Evidence that there is actually some "hiding" going on:
- Empirical: If we change 'frob(int)' of 'MyBase' to virtual, then g++ issues a
warning.
- Reported on stackoverflow, other people ran into that issue before me:
http://stackoverflow.com/a/6035884/3070326

Expected behaviour from g++: Warn that 'MyDerived::frob(int,int)' hides
'MyBase::frob(int)', although this might be unintuitive for C++ newbies. (Just
like the warning for "a < b < c".)

Actual behaviour: 'frob(int)' is inaccessible when the static type is
'MyDerived'. This means one of the following happens:
- If 'frob(int)' is not called, then g++ silently ignores the situation. BAD! I
want a warning, telling me that 'frob(int, int)' is at fault. (Example:
Attached file, verbatim)
- Otherwise, g++ only lists 'MyDerived::frob(int, int)' as candidate. BAD! I
want another candidate ('MyBase::frob(int)') with the explanation that overload
resolution does not operate across namespaces. (Example: Attached file, with
the 'derived.frob(23);' uncommented.)

Meta-info:
"gcc version 4.9.3 (Debian 4.9.3-3) "
As there is no similar bug report, I assume it has not been fixed by a more
recent version anyway.

[Bug target/67344] PowerPC unrecognizable insn

[amodra at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67344

Alan Modra <amodra at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Target|                            |powerpc64*
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2015-08-25
                 CC|                            |amodra at gmail dot com
          Component|rtl-optimization            |target
            Version|5.0                         |6.0
     Ever confirmed|0                           |1

[Bug target/67344] PowerPC unrecognizable insn

[segher at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67344

Segher Boessenkool <segher at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Target|powerpc64*                  |powerpc*
             Status|NEW                         |ASSIGNED
                 CC|                            |segher at gcc dot gnu.org
           Assignee|unassigned at gcc dot gnu.org      |segher at gcc dot gnu.org

--- Comment #1 from Segher Boessenkool <segher at gcc dot gnu.org> ---
That sounds like I did that.  Oops.

Do you have some nice auto-testcase thing, or do you really
write code like that?  ;-)

[Bug target/67344] PowerPC unrecognizable insn

[anton at samba dot org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67344

--- Comment #2 from Anton Blanchard <anton at samba dot org> ---
I've been trying out csmith, then passing the failing tests through creduce.
Even I do not write code like that :)

[Bug target/67344] PowerPC unrecognizable insn

[segher at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67344

--- Comment #3 from Segher Boessenkool <segher at gcc dot gnu.org> ---
Author: segher
Date: Tue Aug 25 19:32:28 2015
New Revision: 227182

URL: https://gcc.gnu.org/viewcvs?rev=227182&root=gcc&view=rev
Log:
rs6000: Fix PR67344

The "*and<mode>3_imm_dot_shifted" pattern is a define_insn_and_split,
like most "dot" patterns: if its output is not assigned cr0 but some
other cr reg, it splits to a non-dot insn and a compare.

Unfortunately that non-dot insn will clobber cr0 as well.  We could
add another clobber (with "=X,x"), but then that second alternative
is never useful; instead, just remove that second alternative.


2015-08-25  Segher Boessenkool  <segher@kernel.crashing.org>

        PR target/67344
        * config/rs6000/rs6000.md (*and<mode>3_imm_dot_shifted): Change to
        a define_insn, remove second alternative.

Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/config/rs6000/rs6000.md

[Bug target/67344] PowerPC unrecognizable insn

[segher at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67344

Segher Boessenkool <segher at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|---                         |FIXED

--- Comment #4 from Segher Boessenkool <segher at gcc dot gnu.org> ---
Fixed.