diff options
Diffstat (limited to 'gcc/tree-ssa-loop-niter.c')
| -rw-r--r-- | gcc/tree-ssa-loop-niter.c | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/gcc/tree-ssa-loop-niter.c b/gcc/tree-ssa-loop-niter.c index 6547382bbb4..3892a43e213 100644 --- a/gcc/tree-ssa-loop-niter.c +++ b/gcc/tree-ssa-loop-niter.c @@ -1953,6 +1953,51 @@ find_loop_niter (struct loop *loop, edge *exit) return niter ? niter : chrec_dont_know; } +/* Return true if loop is known to have bounded number of iterations. */ + +bool +finite_loop_p (struct loop *loop) +{ + unsigned i; + VEC (edge, heap) *exits = get_loop_exit_edges (loop); + edge ex; + struct tree_niter_desc desc; + bool finite = false; + + if (flag_unsafe_loop_optimizations) + return true; + if ((TREE_READONLY (current_function_decl) + || DECL_PURE_P (current_function_decl)) + && !DECL_LOOPING_CONST_OR_PURE_P (current_function_decl)) + { + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, "Found loop %i to be finite: it is within pure or const function.\n", + loop->num); + return true; + } + + exits = get_loop_exit_edges (loop); + for (i = 0; VEC_iterate (edge, exits, i, ex); i++) + { + if (!just_once_each_iteration_p (loop, ex->src)) + continue; + + if (number_of_iterations_exit (loop, ex, &desc, false)) + { + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, "Found loop %i to be finite: iterating ", loop->num); + print_generic_expr (dump_file, desc.niter, TDF_SLIM); + fprintf (dump_file, " times\n"); + } + finite = true; + break; + } + } + VEC_free (edge, heap, exits); + return finite; +} + /* Analysis of a number of iterations of a loop by a brute-force evaluation. |