PR middle-end/55079

	* tree-ssa-loop-niter.c (number_of_iterations_exit): Update
	MAX field if NITER was folded to contant.
	(record_estimate): Sanity check.
	* tree-ssa-loop-ivcanon.c (remove_exits_and_undefined_stmts): New
	function.
	(remove_redundant_iv_test): New function.
	(loops_to_unloop, loops_to_unloop_nunroll): New static vars.
	(unloop_loops): Break out from ...
	(try_unroll_loop_completely): ... here; Pass in MAXITER; use
	remove_exits_and_undefined_stmts; do not unloop.
	(canonicalize_loop_induction_variables): Compute MAXITER;
	use remove_redundant_iv_test; remove loop_close_ssa_invalidated
	and irred_invalidated arguments.
	(canonicalize_induction_variables): Compute fresh bound estimates;
	unloop; walk from innermost.
	(tree_unroll_loops_completely): Likewise.

	* gcc.dg/tree-ssa/cunroll-10.c: New testcase.
	* gcc.dg/tree-ssa/cunroll-9.c: New testcase.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@193098 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 6 insertions, 0 deletions

diff --git a/gcc/tree-ssa-loop-niter.c b/gcc/tree-ssa-loop-niter.c
index 20681a9140a..b77bcbbe5ba 100644
--- a/gcc/tree-ssa-loop-niter.c
+++ b/gcc/tree-ssa-loop-niter.c
@@ -1880,6 +1880,10 @@ number_of_iterations_exit (struct loop *loop, edge exit,
 
   fold_undefer_and_ignore_overflow_warnings ();
 
+  /* If NITER has simplified into a constant, update MAX.  */
+  if (TREE_CODE (niter->niter) == INTEGER_CST)
+    niter->max = tree_to_double_int (niter->niter);
+
   if (integer_onep (niter->assumptions))
     return true;
 
@@ -2556,6 +2560,8 @@ record_estimate (struct loop *loop, tree bound, double_int i_bound,
      real number of iterations.  */
   if (TREE_CODE (bound) != INTEGER_CST)
     realistic = false;
+  else
+    gcc_checking_assert (i_bound == tree_to_double_int (bound));
   if (!upper && !realistic)
     return;