From 1b793819d037eb289923368c5633536e4aa63444 Mon Sep 17 00:00:00 2001 From: amker Date: Fri, 22 Jul 2016 13:22:03 +0000 Subject: * tree-ssa-loop-niter.h (number_of_iterations_exit_assumptions): New Parameter. * tree-ssa-loop-niter.c (number_of_iterations_exit_assumptions): New Parameter. (number_of_iterations_exit): Warn missed loop optimization for possible infinite loops. gcc/testsuite * gcc.dg/tree-ssa/pr19210-1.c: Refine test strings. * gcc.dg/tree-ssa/pr19210-2.c: Delete. git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@238641 138bc75d-0d04-0410-961f-82ee72b054a4 --- gcc/tree-ssa-loop-niter.c | 27 ++++++++++++++++++++++----- 1 file changed, 22 insertions(+), 5 deletions(-) (limited to 'gcc/tree-ssa-loop-niter.c') diff --git a/gcc/tree-ssa-loop-niter.c b/gcc/tree-ssa-loop-niter.c index 3b4d4f31502..ee6d5cfe0fd 100644 --- a/gcc/tree-ssa-loop-niter.c +++ b/gcc/tree-ssa-loop-niter.c @@ -2132,12 +2132,13 @@ loop_only_exit_p (const struct loop *loop, const_edge exit) in comments at struct tree_niter_desc declaration), false otherwise. When EVERY_ITERATION is true, only tests that are known to be executed every iteration are considered (i.e. only test that alone bounds the loop). - */ + If AT_STMT is not NULL, this function stores LOOP's condition statement in + it when returning true. */ bool number_of_iterations_exit_assumptions (struct loop *loop, edge exit, struct tree_niter_desc *niter, - bool every_iteration) + gcond **at_stmt, bool every_iteration) { gimple *last; gcond *stmt; @@ -2254,6 +2255,9 @@ number_of_iterations_exit_assumptions (struct loop *loop, edge exit, if (TREE_CODE (niter->niter) == INTEGER_CST) niter->max = wi::to_widest (niter->niter); + if (at_stmt) + *at_stmt = stmt; + return (!integer_zerop (niter->assumptions)); } @@ -2263,13 +2267,26 @@ number_of_iterations_exit_assumptions (struct loop *loop, edge exit, bool number_of_iterations_exit (struct loop *loop, edge exit, struct tree_niter_desc *niter, - bool, bool every_iteration) + bool warn, bool every_iteration) { + gcond *stmt; if (!number_of_iterations_exit_assumptions (loop, exit, niter, - every_iteration)) + &stmt, every_iteration)) return false; - return (integer_nonzerop (niter->assumptions)); + if (integer_nonzerop (niter->assumptions)) + return true; + + if (warn) + { + const char *wording; + + wording = N_("missed loop optimization, the loop counter may overflow"); + warning_at (gimple_location_safe (stmt), + OPT_Wunsafe_loop_optimizations, "%s", gettext (wording)); + } + + return false; } /* Try to determine the number of iterations of LOOP. If we succeed, -- cgit v1.2.1