re PR tree-optimization/55079 (false positive -Warray-bounds (also seen at -O3 bootstrap))

	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.

From-SVN: r193098

gcc/ChangeLog

+2012-11-02  Jan Hubicka  <jh@suse.cz>
+
+	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.
+
 2012-11-02  Vladimir Makarov  <vmakarov@redhat.com>
 
 	PR middle-end/55130

gcc/testsuite/ChangeLog

+2012-11-02  Jan Hubicka  <jh@suse.cz>
+
+	* gcc.dg/tree-ssa/cunroll-10.c: New testcase.
+	* gcc.dg/tree-ssa/cunroll-9.c: New testcase.
+
 2012-11-02  Vladimir Makarov  <vmakarov@redhat.com>
 
 	PR middle-end/55130

gcc/testsuite/gcc.dg/tree-ssa/cunroll-10.c

+/* { dg-do compile } */
+/* { dg-options "-O3 -Warray-bounds -fdump-tree-cunroll-details" } */
+int a[3];
+int b[4];
+main()
+{
+  int i;
+  for (i=0;i<4;i++)
+    if (b[i]==2)
+     a[i]++;
+}
+/* { dg-final { scan-tree-dump-times "Forced statement unreachable" 2 "cunroll" } } */
+/* { dg-final { cleanup-tree-dump "cunroll" } } */

gcc/testsuite/gcc.dg/tree-ssa/cunroll-9.c

+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-cunrolli" } */
+void abort (void);
+int a[10];
+int b[11];
+t (int n)
+{
+  int i;
+  int sum = 0;
+  for (i = 0; i < n; i++)
+    {
+      if (i > 1000)
+	abort ();
+      if (q ())
+	sum += a[i];
+      else
+	sum += b[i];
+    }
+  return sum;
+}
+/* { dg-final { scan-tree-dump-times 1 "Removed pointless exit:" "cunroli" } } */
+/* { dg-final { cleanup-tree-dump "cunroli" } } */

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;