[Bug tree-optimization/103204] New: [11/12 Regression] ICE: in vn_reference_insert_pieces, at tree-ssa-sccvn.c:3842 (on -O2 and above)

[haoxintu at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103204

            Bug ID: 103204
           Summary: [11/12 Regression] ICE: in vn_reference_insert_pieces,
                    at tree-ssa-sccvn.c:3842 (on -O2 and above)
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Keywords: ice-on-valid-code
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: haoxintu at gmail dot com
  Target Milestone: ---

Hi all.

$cat small.c
#include <stdint.h>
int a[][1];
int b, c;
void d() {
  int32_t e;
  int32_t f[0];
  int32_t *g;
  for (; e;)
    c = b;
  if (a[0][b] = f != 3)
    g = &f[b];
  int32_t h;
  *g = *g = *g = h;
}

$gcc -w -O2 small.c
during GIMPLE pass: fre
small.c: In function ‘d’:
small.c:14:1: internal compiler error: in vn_reference_insert_pieces, at
tree-ssa-sccvn.c:3842
   14 | }
      | ^
0x6abce4 vn_reference_insert_pieces(tree_node*, int, int, tree_node*,
vec<vn_reference_op_struct, va_heap, vl_ptr>, tree_node*, unsigned int)
        ../../gcc/tree-ssa-sccvn.c:3842
0xdbad48 vn_reference_lookup_or_insert_for_pieces
        ../../gcc/tree-ssa-sccvn.c:2339
0xdbad48 vn_walk_cb_data::finish(int, int, tree_node*)
        ../../gcc/tree-ssa-sccvn.c:1900
0xdc12ae vn_reference_lookup_3
        ../../gcc/tree-ssa-sccvn.c:3160
0xd04652 walk_non_aliased_vuses(ao_ref*, tree_node*, bool, void* (*)(ao_ref*,
tree_node*, void*), void* (*)(ao_ref*, tree_node*, void*, translate_flags*),
tree_node* (*)(tree_node*), unsigned int&, void*)
        ../../gcc/tree-ssa-alias.c:3725
0xdbc140 vn_reference_lookup(tree_node*, tree_node*, vn_lookup_kind,
vn_reference_s**, bool, tree_node**, tree_node*)
        ../../gcc/tree-ssa-sccvn.c:3700
0xdbc911 eliminate_dom_walker::eliminate_stmt(basic_block_def*,
gimple_stmt_iterator*)
        ../../gcc/tree-ssa-sccvn.c:6384
0xdbe1dd eliminate_dom_walker::before_dom_children(basic_block_def*)
        ../../gcc/tree-ssa-sccvn.c:6722
0xdbe1dd eliminate_dom_walker::before_dom_children(basic_block_def*)
        ../../gcc/tree-ssa-sccvn.c:6655
0x17a286e dom_walker::walk(basic_block_def*)
        ../../gcc/domwalk.c:309
0xdb57aa eliminate_with_rpo_vn(bitmap_head*)
        ../../gcc/tree-ssa-sccvn.c:6902
0xdc47c3 do_rpo_vn
        ../../gcc/tree-ssa-sccvn.c:8014
0xdc5670 execute
        ../../gcc/tree-ssa-sccvn.c:8096
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <https://gcc.gnu.org/bugs/> for instructions.

$gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/media/haoxin/SeagateData/haoxin-data/dut-research/compilers/gcc/build/bin/../libexec/gcc/x86_64-pc-linux-gnu/12.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../configure
--prefix=/home/haoxin/haoxin-data/dut-research/compilers/gcc/build/
--enable-bootstrap --enable-checking=release --enable-languages=c,c++
--enable-multilib
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 12.0.0 20211112 (experimental) (GCC) 


Note that GCC-11.2 above versions behave the same.

Can check here: https://godbolt.org/z/WP8naWWMz


Thanks,
Haoxin