[Bug c/102118] New: ice in merge, at ipa-modref-tree.h:203

["dcb314 at hotmail dot com" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102118

            Bug ID: 102118
           Summary: ice in merge, at ipa-modref-tree.h:203
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: dcb314 at hotmail dot com
  Target Milestone: ---

For this C code:

typedef struct {
  int large_page_addr;
  long n_used_entries
} CPUTLBDesc;
typedef struct {
  long mask
} CPUTLBDescFast;
typedef struct {
  CPUTLBDesc d[8];
  CPUTLBDescFast f[]
} CPUTLB;
typedef int RISCVCPU;
CPUTLB *tlb_flush_page_bits_locked___trans_tmp_8,
    *tlb_flush_page_bits_locked___trans_tmp_6,
    *tlb_flush_page_bits_locked___trans_tmp_4;
void tlb_flush_page_bits_locked(int *env, int midx) {
  {
    int *__trans_tmp_5 = env;
    {
      RISCVCPU *arch_cpu = __trans_tmp_5;
      tlb_flush_page_bits_locked___trans_tmp_4 = arch_cpu;
    }
  }
  CPUTLBDesc *d = &tlb_flush_page_bits_locked___trans_tmp_4->d[midx];
  {
    int *__trans_tmp_7 = env;
    {
      RISCVCPU *arch_cpu = __trans_tmp_7;
      tlb_flush_page_bits_locked___trans_tmp_6 = arch_cpu;
    }
  }
  if (tlb_flush_page_bits_locked___trans_tmp_6->f[midx].mask)
    if (d->large_page_addr) {
      int *__trans_tmp_3 = env;
      {
        {
          RISCVCPU *arch_cpu = __trans_tmp_3;
          tlb_flush_page_bits_locked___trans_tmp_8 = arch_cpu;
        }
        tlb_flush_page_bits_locked___trans_tmp_8->d[midx].n_used_entries--;
      }
    }
}

compiled by recent gcc trunk and compiler flag -O1, does this:

during GIMPLE pass: modref
bug752.c: In function ‘tlb_flush_page_bits_locked’:
bug752.c:43:1: internal compiler error: in merge, at ipa-modref-tree.h:203
   43 | }
      | ^
0xae7448 modref_access_node::merge(modref_access_node const&, bool)
        ../../trunk.git/gcc/ipa-modref-tree.h:203


The code was fine at git hash 3ac6b5cff1eca4e1 and broken at hash
e28ac73af20028f8