re PR tree-optimization/27144 (segfault with -O2 on x86_64 (and powerpc64))

	PR tree-optimization/27144
	* tree-ssa-loop-niter.c (derive_constant_upper_bound): New function.
	(record_estimate): Only record constant upper bound.
	(infer_loop_bounds_from_undefined): Call
	compute_estimated_nb_iterations just once.
	(proved_non_wrapping_p): Renamed to ...
	(n_of_executions_at_most): ... this.  Expect bound to be a constant.
	(convert_step_widening, scev_probably_wraps_p): Call
	n_of_executions_at_most instead of proved_non_wrapping_p.
	(substitute_in_loop_info): Do not replace values in bounds.
	* cfgloop.h (struct nb_iter_bound): Remove "additional" field.  Update
	comments.

	* gcc.dg/tree-ssa/loop-16.c: New test.

From-SVN: r113425

1 files changed, 4 insertions, 6 deletions

diff --git a/gcc/cfgloop.h b/gcc/cfgloop.h
index 9805d4c..f04c5d6 100644
--- a/gcc/cfgloop.h
+++ b/gcc/cfgloop.h
@@ -47,12 +47,10 @@ struct lpt_decision
 
 struct nb_iter_bound
 {
-  tree bound;		/* The expression whose value is an upper bound on the
-			   number of executions of anything after ...  */
-  tree at_stmt;		/* ... this statement during one execution of loop.  */
-  tree additional;	/* A conjunction of conditions the operands of BOUND
-			   satisfy.  The additional information about the value
-			   of the bound may be derived from it.  */
+  tree bound;		/* The constant expression whose value is an upper
+			   bound on the number of executions of ...  */
+  tree at_stmt;		/* ... this statement during one execution of
+			   a loop.  */
   struct nb_iter_bound *next;
 			/* The next bound in a list.  */
 };