[Bug ipa/103073] [12 Regression] ICE in insert_access, at ipa-modref-tree.h:578 since r12-4401-gfecd145359fc981b

[hubicka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103073

Jan Hubicka <hubicka at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |rguenther at suse dot de

--- Comment #5 from Jan Hubicka <hubicka at gcc dot gnu.org> ---
OK, after some inlining we produce an access past the end of array which makes
get_base_ref_and_extend to produce an access with size==8 and max_size==0.
Modref access merging is built on an assumption that max_size>size (if both are
known).

The access is (*g_18(D))[3][_207];:
 <array_ref 0x7ffff756f0e0
    type <boolean_type 0x7ffff73ebb28 bool public unsigned type_6 QI
        size <integer_cst 0x7ffff73ed030 constant 8>
        unit-size <integer_cst 0x7ffff73ed048 constant 1>
        align:8 warn_if_not_align:0 symtab:0 alias-set 1 canonical-type
0x7ffff73ebb28 precision:1 min <integer_cst 0x7ffff73ed288 0> max <integer_cst
0x7ffff73ed2b8 1>
        pointer_to_this <pointer_type 0x7ffff7534bd0>>

    arg:0 <array_ref 0x7ffff756f118
        type <array_type 0x7ffff7534dc8 type <boolean_type 0x7ffff73ebb28 bool>
            type_6 BLK
            size <integer_cst 0x7ffff7541ae0 constant 168>
            unit-size <integer_cst 0x7ffff7541ab0 constant 21>
            align:8 warn_if_not_align:0 symtab:0 alias-set 1 canonical-type
0x7ffff7534dc8 domain <integer_type 0x7ffff7534d20>>

        arg:0 <mem_ref 0x7ffff7566cd0 type <array_type 0x7ffff7534f18>

            arg:0 <ssa_name 0x7ffff754d630 type <pointer_type 0x7ffff7534348>
                visited var <parm_decl 0x7ffff7548180 g>
                def_stmt GIMPLE_NOP
                version:18
                ptr-info 0x7ffff7541f60>
            arg:1 <integer_cst 0x7ffff7541e88 constant 0>
            tt.C:5:14 start: tt.C:5:11 finish: tt.C:5:14>
        arg:1 <integer_cst 0x7ffff73ed300 constant 3>
        tt.C:5:17 start: tt.C:5:11 finish: tt.C:5:17>
    arg:1 <ssa_name 0x7ffff756eca8
        type <integer_type 0x7ffff73eb690 unsigned int sizes-gimplified public
unsigned SI
            size <integer_cst 0x7ffff73ed180 constant 32>
            unit-size <integer_cst 0x7ffff73ed198 constant 4>
            align:32 warn_if_not_align:0 symtab:0 alias-set -1 canonical-type
0x7ffff73eb690 precision:32 min <integer_cst 0x7ffff73ed1b0 0> max <integer_cst
0x7ffff73ed168 4294967295>
            pointer_to_this <pointer_type 0x7ffff73fb498>>
        visited
        def_stmt _207 = _293 + 21;
        version:207
        ptr-info 0x7ffff7567860>
    tt.C:5:24 start: tt.C:5:11 finish: tt.C:5:24>

and we get maxsize reduced based on value range info:
582                                           TYPE_PRECISION (sizetype));
583                             woffset *= wi::to_offset (unit_size);
584                             woffset <<= LOG2_BITS_PER_UNIT;
585                             bit_offset += woffset;
586                             if (known_size_p (maxsize))
587                               maxsize -= woffset;
588                           }
589                       }
590                   }
(gdb) p woffset
$114 = {<poly_int_pod<1, generic_wide_int<fixed_wide_int_storage<128> > >> =
{coeffs = {{<fixed_wide_int_storage<128>> = {val = {168, 0, 140737488345944},
len = 1}, static is_sign_extended = true}}}, <No data fields>}
(gdb) p maxsize
$115 = {<poly_int_pod<1, generic_wide_int<fixed_wide_int_storage<128> > >> =
{coeffs = {{<fixed_wide_int_storage<128>> = {val = {168, 0, 140737488346016},
len = 1}, static is_sign_extended = true}}}, <No data fields>}

I suppose we can ignore such paradoxical range becuase executing that code
undefined.  But I think we may want to handle this in alias oracle as well?