Concretize gimple_cond_make_{false|true}

This corresponds to:
  [PATCH 71/89] Concretize gimple_cond_make_{false|true}
  https://gcc.gnu.org/ml/gcc-patches/2014-04/msg01208.html
from the original 89-patch kit

That earlier patch was approved by Jeff:
> OK once prerequisites go in.
in https://gcc.gnu.org/ml/gcc-patches/2014-05/msg00863.html

gcc/
	* gimple.h (gimple_cond_make_false): Require a gimple_cond.
	(gimple_cond_make_true): Likewise.

	* tree-cfg.c (fold_cond_expr_cond): Add a checked cast to
	gimple_cond within region guarded by check for GIMPLE_COND.
	* tree-ssa-ccp.c (ccp_fold_stmt): Likewise.

	* tree-loop-distribution.c (generate_loops_for_partition): Replace
	a check for GIMPLE_COND with a dyn_cast<gimple_cond>.
	* tree-ssa-ccp.c (optimize_unreachable): Likewise.
	* tree-ssa-loop-niter.c (number_of_iterations_exit): Likewise.
	* tree-ssa-pre.c (eliminate_dom_walker::before_dom_children):
	Likewise.

	* tree-vrp.c (fold_predicate_in): Add a checked cast to
	gimple_cond.  We must be dealing with a GIMPLE_COND since logic
	at top of the function ensures we only act on GIMPLE_ASSIGN and
	GIMPLE_COND statements, and we're now within a "not a GIMPLE_ASSIGN"
	clause.

	* tree-ssa-loop-ivcanon.c (remove_exits_and_undefined_stmts): Add
	checked cast of elt->stmt to gimple_cond.  The existing code requires
	this to be a GIMPLE_COND, though it's not clear to me how this
	requirement is enforced.
	(remove_redundant_iv_tests): Likewise.
	(try_unroll_loop_completely): Likewise, for the last_stmt of the
	preceding bb along edge_to_cancel.
	* tree-ssa-reassoc.c (maybe_optimize_range_tests): Likewise, for the
	last_stmt of bb.

1 files changed, 9 insertions, 8 deletions

diff --git a/gcc/tree-ssa-loop-ivcanon.c b/gcc/tree-ssa-loop-ivcanon.c
index 00cbf8ff538..b70f1182cf5 100644
--- a/gcc/tree-ssa-loop-ivcanon.c
+++ b/gcc/tree-ssa-loop-ivcanon.c
@@ -521,11 +521,12 @@ remove_exits_and_undefined_stmts (struct loop *loop, unsigned int npeeled)
 	  if (!loop_exit_edge_p (loop, exit_edge))
 	    exit_edge = EDGE_SUCC (bb, 1);
 	  gcc_checking_assert (loop_exit_edge_p (loop, exit_edge));
+	  gimple_cond cond_stmt = as_a <gimple_cond> (elt->stmt);
 	  if (exit_edge->flags & EDGE_TRUE_VALUE)
-	    gimple_cond_make_true (elt->stmt);
+	    gimple_cond_make_true (cond_stmt);
 	  else
-	    gimple_cond_make_false (elt->stmt);
-	  update_stmt (elt->stmt);
+	    gimple_cond_make_false (cond_stmt);
+	  update_stmt (cond_stmt);
 	  changed = true;
 	}
     }
@@ -574,11 +575,12 @@ remove_redundant_iv_tests (struct loop *loop)
 	      fprintf (dump_file, "Removed pointless exit: ");
 	      print_gimple_stmt (dump_file, elt->stmt, 0, 0);
 	    }
+	  gimple_cond cond_stmt = as_a <gimple_cond> (elt->stmt);
 	  if (exit_edge->flags & EDGE_TRUE_VALUE)
-	    gimple_cond_make_false (elt->stmt);
+	    gimple_cond_make_false (cond_stmt);
 	  else
-	    gimple_cond_make_true (elt->stmt);
-	  update_stmt (elt->stmt);
+	    gimple_cond_make_true (cond_stmt);
+	  update_stmt (cond_stmt);
 	  changed = true;
 	}
     }
@@ -658,7 +660,6 @@ try_unroll_loop_completely (struct loop *loop,
 			    location_t locus)
 {
   unsigned HOST_WIDE_INT n_unroll, ninsns, max_unroll, unr_insns;
-  gimple cond;
   struct loop_size size;
   bool n_unroll_found = false;
   edge edge_to_cancel = NULL;
@@ -855,7 +856,7 @@ try_unroll_loop_completely (struct loop *loop,
   /* Remove the conditional from the last copy of the loop.  */
   if (edge_to_cancel)
     {
-      cond = last_stmt (edge_to_cancel->src);
+      gimple_cond cond = as_a <gimple_cond> (last_stmt (edge_to_cancel->src));
       if (edge_to_cancel->flags & EDGE_TRUE_VALUE)
 	gimple_cond_make_false (cond);
       else