[Bug c++/66211] New: Rvalue conversion in ternary operator causes internal compiler error

[Bug c++/66211] New: Rvalue conversion in ternary operator causes internal compiler error

[vgheorgh at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66211

            Bug ID: 66211
           Summary: Rvalue conversion in ternary operator causes internal
                    compiler error
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: vgheorgh at gmail dot com
  Target Milestone: ---

The code below

void f(int&){}

int main()
{
    int x = 0;
    double y = 1;
    f(1 > 0 ? x : y);
}

should not compile, due to rvalue conversion in the ternary operator, then
trying to bind the rvalue to a non-constant reference. However, gcc51 and gcc6
HEAD crash with an internal compiler error

     internal compiler error: in convert_like_real, at cp/call.c:6471

gcc49 works (emits an error)

[Bug c++/66211] [5/6 Regression] Rvalue conversion in ternary operator causes internal compiler error

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66211

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2015-05-20
                 CC|                            |jakub at gcc dot gnu.org
   Target Milestone|---                         |5.2
            Summary|Rvalue conversion in        |[5/6 Regression] Rvalue
                   |ternary operator causes     |conversion in ternary
                   |internal compiler error     |operator causes internal
                   |                            |compiler error
     Ever confirmed|0                           |1

--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Started with r217279.

[Bug c++/66211] [5/6 Regression] Rvalue conversion in ternary operator causes internal compiler error

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66211

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
           Assignee|unassigned at gcc dot gnu.org      |rguenth at gcc dot gnu.org

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
I will have a look.

[Bug c++/66211] [5/6 Regression] Rvalue conversion in ternary operator causes internal compiler error

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66211

--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
So we fold (and did fold before) 1 > 0 ? x : y to (float) x (thus an rvalue).
Then later we call ocp_convert on that requesting a conversion to int which
does

810           converted = fold_if_not_in_template (convert_to_integer (type,
e));

where convert_to_integer ends up just doing

910             return build1 (FIX_TRUNC_EXPR, type, expr);

and fold then applying the simplification

   /* If we are converting an integer to a floating-point that can
      represent it exactly and back to an integer, we can skip the
      floating-point conversion.  */
   (if (inside_int && inter_float && final_int &&
        (unsigned) significand_size (TYPE_MODE (inter_type))
        >= inside_prec - !inside_unsignedp)
    (convert @0))))))

and

(for cvt (convert view_convert float fix_trunc)
 (simplify
  (cvt @0)
  (if ((GIMPLE && useless_type_conversion_p (type, TREE_TYPE (@0)))
       || (GENERIC && type == TREE_TYPE (@0)))
   @0)))

where wrapping the result as (non_lvalue @0) fixes the regression.  The bug
is of course the C++ frontend folding stuff too early (and too aggressive)
here.

But for GCC 5 the above might be a good-enough workaround (eventually
we can conditionalize building non_lvalue exprs to non-C-frontends).

[Bug c++/66211] [5/6 Regression] Rvalue conversion in ternary operator causes internal compiler error

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66211

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jason at redhat dot com
            Version|unknown                     |5.1.0

--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> ---
Unfortunately this causes

FAIL: gcc.dg/tree-ssa/foldcast-1.c scan-tree-dump-times original "return x;" 2
FAIL: gcc.dg/tree-ssa/pr31261.c scan-tree-dump-times original "return b & 7;" 1

FAIL: gfortran.dg/assumed_type_2.f90   -O0   scan-tree-dump-times original
"sub_
scalar .\\\\(struct t1 .\\\\) array_class_t1_ptr._data.dat" 1
FAIL: gfortran.dg/assumed_type_2.f90   -O1   scan-tree-dump-times original
"sub_
scalar .\\\\(struct t1 .\\\\) array_class_t1_ptr._data.dat" 1
FAIL: gfortran.dg/assumed_type_2.f90   -O2   scan-tree-dump-times original
"sub_
scalar .\\\\(struct t1 .\\\\) array_class_t1_ptr._data.dat" 1
FAIL: gfortran.dg/assumed_type_2.f90   -O3 -fomit-frame-pointer  
scan-tree-dump
-times original "sub_scalar .\\\\(struct t1 .\\\\)
array_class_t1_ptr._data.dat"
 1
FAIL: gfortran.dg/assumed_type_2.f90   -O3 -fomit-frame-pointer
-funroll-all-loo
ps -finline-functions   scan-tree-dump-times original "sub_scalar .\\\\(struct
t
1 .\\\\) array_class_t1_ptr._data.dat" 1
FAIL: gfortran.dg/assumed_type_2.f90   -O3 -fomit-frame-pointer -funroll-loops  
 scan-tree-dump-times original "sub_scalar .\\\\(struct t1 .\\\\)
array_class_t1
_ptr._data.dat" 1
FAIL: gfortran.dg/assumed_type_2.f90   -O3 -g   scan-tree-dump-times original
"s
ub_scalar .\\\\(struct t1 .\\\\) array_class_t1_ptr._data.dat" 1
FAIL: gfortran.dg/assumed_type_2.f90   -Os   scan-tree-dump-times original
"sub_
scalar .\\\\(struct t1 .\\\\) array_class_t1_ptr._data.dat" 1
FAIL: gfortran.dg/c_f_pointer_tests_3.f90   -O   scan-tree-dump-times original
"
 fptr_array.data = cptr;" 1
FAIL: gfortran.dg/c_loc_test_22.f90   -O   scan-tree-dump-times original
"D.[0-9
]+ = parm.[0-9]+.data;[^;]+ptr[1-4] = D.[0-9]+;" 4
FAIL: gfortran.dg/c_ptr_tests_14.f90   -O0   scan-tree-dump-times original
"fgsl
_file.[0-9]+.gsl_file = c_ptr.[0-9]+;" 1
FAIL: gfortran.dg/c_ptr_tests_14.f90   -O0   scan-tree-dump-times original
"fgsl
_file.[0-9]+.gsl_func = c_funptr.[0-9]+;" 1
FAIL: gfortran.dg/c_ptr_tests_14.f90   -O1   scan-tree-dump-times original
"fgsl
_file.[0-9]+.gsl_file = c_ptr.[0-9]+;" 1
FAIL: gfortran.dg/c_ptr_tests_14.f90   -O1   scan-tree-dump-times original
"fgsl
_file.[0-9]+.gsl_func = c_funptr.[0-9]+;" 1
FAIL: gfortran.dg/c_ptr_tests_14.f90   -O2   scan-tree-dump-times original
"fgsl
_file.[0-9]+.gsl_file = c_ptr.[0-9]+;" 1
FAIL: gfortran.dg/c_ptr_tests_14.f90   -O2   scan-tree-dump-times original
"fgsl
_file.[0-9]+.gsl_func = c_funptr.[0-9]+;" 1
FAIL: gfortran.dg/c_ptr_tests_14.f90   -O3 -fomit-frame-pointer  
scan-tree-dump
-times original "fgsl_file.[0-9]+.gsl_file = c_ptr.[0-9]+;" 1
FAIL: gfortran.dg/c_ptr_tests_14.f90   -O3 -fomit-frame-pointer  
scan-tree-dump
-times original "fgsl_file.[0-9]+.gsl_func = c_funptr.[0-9]+;" 1
FAIL: gfortran.dg/c_ptr_tests_14.f90   -O3 -fomit-frame-pointer
-funroll-all-loo
ps -finline-functions   scan-tree-dump-times original
"fgsl_file.[0-9]+.gsl_file
 = c_ptr.[0-9]+;" 1
FAIL: gfortran.dg/c_ptr_tests_14.f90   -O3 -fomit-frame-pointer
-funroll-all-loo
ps -finline-functions   scan-tree-dump-times original
"fgsl_file.[0-9]+.gsl_func
 = c_funptr.[0-9]+;" 1
FAIL: gfortran.dg/c_ptr_tests_14.f90   -O3 -fomit-frame-pointer -funroll-loops  
 scan-tree-dump-times original "fgsl_file.[0-9]+.gsl_file = c_ptr.[0-9]+;" 1
FAIL: gfortran.dg/c_ptr_tests_14.f90   -O3 -fomit-frame-pointer -funroll-loops  
 scan-tree-dump-times original "fgsl_file.[0-9]+.gsl_func = c_funptr.[0-9]+;" 1
FAIL: gfortran.dg/c_ptr_tests_14.f90   -O3 -g   scan-tree-dump-times original
"f
gsl_file.[0-9]+.gsl_file = c_ptr.[0-9]+;" 1
FAIL: gfortran.dg/c_ptr_tests_14.f90   -O3 -g   scan-tree-dump-times original
"f
gsl_file.[0-9]+.gsl_func = c_funptr.[0-9]+;" 1
FAIL: gfortran.dg/c_ptr_tests_14.f90   -Os   scan-tree-dump-times original
"fgsl
_file.[0-9]+.gsl_file = c_ptr.[0-9]+;" 1
FAIL: gfortran.dg/c_ptr_tests_14.f90   -Os   scan-tree-dump-times original
"fgsl
_file.[0-9]+.gsl_func = c_funptr.[0-9]+;" 1
FAIL: gfortran.dg/c_ptr_tests_15.f90   -O   scan-tree-dump-times original
"fgsl_
file.[0-9]+.gsl_file = c_ptr.[0-9]+;" 1
FAIL: gfortran.dg/c_ptr_tests_15.f90   -O   scan-tree-dump-times original
"fgsl_
file.[0-9]+.gsl_func = c_funptr.[0-9]+;" 1
FAIL: gfortran.dg/coarray_31.f90   -O   scan-tree-dump original
"a.y.d._data.dat
a = D.[0-9]+.y.d._data.data;"
FAIL: gfortran.dg/coarray_31.f90   -O   scan-tree-dump original "a.y.x.data =
D.
[0-9]+.y.x.data;"
FAIL: gfortran.dg/coarray_31.f90   -O   scan-tree-dump original
"a.y.z._data.dat
a = D.[0-9]+.y.z._data.data;"
FAIL: gfortran.dg/no_arg_check_2.f90   -O0   scan-tree-dump-times original
"sub_
scalar .\\\\(struct t1 .\\\\) array_class_t1_ptr._data.dat" 1
FAIL: gfortran.dg/no_arg_check_2.f90   -O1   scan-tree-dump-times original
"sub_
scalar .\\\\(struct t1 .\\\\) array_class_t1_ptr._data.dat" 1
FAIL: gfortran.dg/no_arg_check_2.f90   -O2   scan-tree-dump-times original
"sub_
scalar .\\\\(struct t1 .\\\\) array_class_t1_ptr._data.dat" 1
FAIL: gfortran.dg/no_arg_check_2.f90   -O3 -fomit-frame-pointer  
scan-tree-dump
-times original "sub_scalar .\\\\(struct t1 .\\\\)
array_class_t1_ptr._data.dat"
 1
FAIL: gfortran.dg/no_arg_check_2.f90   -O3 -fomit-frame-pointer
-funroll-all-loo
ps -finline-functions   scan-tree-dump-times original "sub_scalar .\\\\(struct
t
1 .\\\\) array_class_t1_ptr._data.dat" 1
FAIL: gfortran.dg/no_arg_check_2.f90   -O3 -fomit-frame-pointer -funroll-loops  
 scan-tree-dump-times original "sub_scalar .\\\\(struct t1 .\\\\)
array_class_t1
_ptr._data.dat" 1
FAIL: gfortran.dg/no_arg_check_2.f90   -O3 -g   scan-tree-dump-times original
"s
ub_scalar .\\\\(struct t1 .\\\\) array_class_t1_ptr._data.dat" 1
FAIL: gfortran.dg/no_arg_check_2.f90   -Os   scan-tree-dump-times original
"sub_
scalar .\\\\(struct t1 .\\\\) array_class_t1_ptr._data.dat" 1

FAIL: gnat.dg/ice_type.adb (test for excess errors) (ICE in build_binary_op, at
ada/gcc-interface/utils2.c:906)
FAIL: gnat.dg/specs/addr1.ads  (test for warnings, line 30)


not yet further analyzed.

IMHO the C++ frontend shouldn't rely on fold preserving rvalue-ness but it
should perform these checks before folding like the C frontend does.


I'll look at the above failures later this week to see if there is anything
obvious that can be improved.

[Bug c++/66211] [5/6 Regression] Rvalue conversion in ternary operator causes internal compiler error

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66211

--- Comment #5 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Perhaps just guard this particular match.pd pattern with GIMPLE guard for now
(until the delayed C++ folding is committed)?

[Bug c++/66211] [5 Regression] Rvalue conversion in ternary operator causes internal compiler error

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66211

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
      Known to work|                            |6.0
            Summary|[5/6 Regression] Rvalue     |[5 Regression] Rvalue
                   |conversion in ternary       |conversion in ternary
                   |operator causes internal    |operator causes internal
                   |compiler error              |compiler error
      Known to fail|                            |5.1.0

--- Comment #7 from Richard Biener <rguenth at gcc dot gnu.org> ---
Fixed on trunk sofar.

--- Comment #8 from Richard Biener <rguenth at gcc dot gnu.org> ---
Author: rguenth
Date: Thu May 21 13:23:41 2015
New Revision: 223483

URL: https://gcc.gnu.org/viewcvs?rev=223483&root=gcc&view=rev
Log:
2015-05-21  Richard Biener  <rguenther@suse.de>

        PR c++/66211
        * match.pd: Guard pattern optimzing (int)(float)int
        conversions to apply only on GIMPLE.

        * g++.dg/conversion/pr66211.C: New testcase.
        * gcc.dg/tree-ssa/forwprop-18.c: Adjust.

Added:
    trunk/gcc/testsuite/g++.dg/conversion/pr66211.C
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/match.pd
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/testsuite/gcc.dg/tree-ssa/forwprop-18.c

[Bug c++/66211] [5 Regression] Rvalue conversion in ternary operator causes internal compiler error

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66211

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
      Known to work|                            |6.0
            Summary|[5/6 Regression] Rvalue     |[5 Regression] Rvalue
                   |conversion in ternary       |conversion in ternary
                   |operator causes internal    |operator causes internal
                   |compiler error              |compiler error
      Known to fail|                            |5.1.0

--- Comment #7 from Richard Biener <rguenth at gcc dot gnu.org> ---
Fixed on trunk sofar.

[Bug c++/66211] [5 Regression] Rvalue conversion in ternary operator causes internal compiler error

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66211

--- Comment #9 from Richard Biener <rguenth at gcc dot gnu.org> ---
Author: rguenth
Date: Wed Jun  3 07:39:06 2015
New Revision: 224059

URL: https://gcc.gnu.org/viewcvs?rev=224059&root=gcc&view=rev
Log:
2015-06-03  Richard Biener  <rguenther@suse.de>

        Backport from mainline
        2015-06-02  Richard Biener  <rguenther@suse.de>

        PR debug/65549
        * dwarf2out.c (lookup_context_die): New function.
        (resolve_addr): Avoid forcing a full DIE for the
        target of a DW_TAG_GNU_call_site during late compilation.
        Instead create a stub DIE without a type if we have a
        context DIE present.

        * g++.dg/lto/pr65549_0.C: New testcase.

        2015-06-01  Richard Biener  <rguenther@suse.de>

        PR tree-optimization/66280
        * tree-vect-slp.c (vect_detect_hybrid_slp_stmts): Fix pattern
        def-use walking.

        * g++.dg/torture/pr66280.C: New testcase.
        * g++.dg/torture/pr66280-2.C: Likewise.

        2015-05-27  Richard Biener  <rguenther@suse.de>

        PR tree-optimization/66272
        Revert parts of
        2014-08-15  Richard Biener  <rguenther@suse.de>

        PR tree-optimization/62031
        * tree-data-ref.c (dr_analyze_indices): Do not set
        DR_UNCONSTRAINED_BASE.
        (dr_may_alias_p): All indirect accesses have to go the
        formerly DR_UNCONSTRAINED_BASE path.
        * tree-data-ref.h (struct indices): Remove
        unconstrained_base member.
        (DR_UNCONSTRAINED_BASE): Remove.

        * gcc.dg/torture/pr66272.c: New testcase.

        2015-05-21  Richard Biener  <rguenther@suse.de>

        PR c++/66211
        * match.pd: Guard pattern optimzing (int)(float)int
        conversions to apply only on GIMPLE.

        * g++.dg/conversion/pr66211.C: New testcase.
        * gcc.dg/tree-ssa/forwprop-18.c: Adjust.

        2015-05-13  Richard Biener  <rguenther@suse.de>

        PR tree-optimization/66123
        * tree-ssa-dom.c (propagate_rhs_into_lhs): Check if we found
        a taken edge.

        * gcc.dg/torture/pr66123.c: New testcase.

Added:
    branches/gcc-5-branch/gcc/testsuite/g++.dg/conversion/pr66211.C
    branches/gcc-5-branch/gcc/testsuite/g++.dg/lto/pr65549_0.C
    branches/gcc-5-branch/gcc/testsuite/g++.dg/torture/pr66280-2.C
    branches/gcc-5-branch/gcc/testsuite/g++.dg/torture/pr66280.C
    branches/gcc-5-branch/gcc/testsuite/gcc.dg/torture/pr66123.c
    branches/gcc-5-branch/gcc/testsuite/gcc.dg/torture/pr66272.c
Modified:
    branches/gcc-5-branch/gcc/ChangeLog
    branches/gcc-5-branch/gcc/dwarf2out.c
    branches/gcc-5-branch/gcc/match.pd
    branches/gcc-5-branch/gcc/testsuite/ChangeLog
    branches/gcc-5-branch/gcc/testsuite/gcc.dg/tree-ssa/forwprop-18.c
    branches/gcc-5-branch/gcc/tree-data-ref.c
    branches/gcc-5-branch/gcc/tree-data-ref.h
    branches/gcc-5-branch/gcc/tree-ssa-dom.c
    branches/gcc-5-branch/gcc/tree-vect-slp.c

[Bug c++/66211] [5 Regression] Rvalue conversion in ternary operator causes internal compiler error

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66211

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
      Known to work|                            |5.2.0
         Resolution|---                         |FIXED

--- Comment #10 from Richard Biener <rguenth at gcc dot gnu.org> ---
Fixed.