[Bug tree-optimization/85475] New: [8 Regression] Compile time hog w/ -O1 -fpeel-loops

[asolokha at gmx dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85475

            Bug ID: 85475
           Summary: [8 Regression] Compile time hog w/ -O1 -fpeel-loops
           Product: gcc
           Version: 8.0
            Status: UNCONFIRMED
          Keywords: compile-time-hog
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: asolokha at gmx dot com
  Target Milestone: ---

gcc-8.0.0-alpha20180415 snapshot (r259389) takes long (or indefinite) time to
compile the following snippet w/ -O1 (-O2) -fpeel-loops:

int
nj (int le)
{
  int zb;

  for (zb = 0; zb < 16; ++zb)
    le += le;

  return le * le;
}

% timeout 20 gcc-8.0.0-alpha20180415 -O1 -fpeel-loops -c i9xivvyu.c
zsh: exit 124   timeout 20 gcc-8.0.0-alpha20180415 -O1 -fpeel-loops -c
i9xivvyu.c

Profile captured by perf top:

  41.29%  cc1  [.] tree_int_cst_equal
  12.86%  cc1  [.] vr_values::get_value_range
  11.46%  cc1  [.] vrp_valueize_1
   7.44%  cc1  [.] gimple_simplify_MULT_EXPR
   4.18%  cc1  [.] integer_all_onesp
   3.75%  cc1  [.] integer_zerop
   2.96%  cc1  [.] range_int_cst_singleton_p
   2.93%  cc1  [.] wi::max_value
   2.29%  cc1  [.] range_int_cst_singleton_p
   2.26%  cc1  [.] gimple_simplify_233
   1.44%  cc1  [.] gimple_resimplify2
   1.08%  cc1  [.] gimple_simplify
   1.03%  cc1  [.] gimple_negate_expr_p
   0.82%  cc1  [.] maybe_push_res_to_seq
   0.73%  cc1  [.] tree_strip_nop_conversions
   0.65%  cc1  [.] tree_int_cst_equal
   0.61%  cc1  [.] tree_swap_operands_p
   0.50%  cc1  [.] real_zerop
   0.41%  cc1  [.] tree_swap_operands_p
   0.38%  cc1  [.] integer_onep
   0.35%  cc1  [.] real_minus_onep
   0.26%  cc1  [.] real_onep
   0.15%  cc1  [.] integer_minus_onep
   0.15%  cc1  [.] commutative_tree_code