re PR tree-optimization/88148 (ICE in tree_nop_conversion_p at gcc/tree.c:12550 since r264273)

2018-11-22  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/88148
	* tree-ssa-loop-niter.c (simplify_replace_tree): Get optional
	valueization callback parameter and handle it.
	* tree-ssa-loop-niter.h (simplify_replace_tree): Export.
	* tree-ssa-sccvn.c (process_bb): Eliminate in loop niter trees.

	* gfortran.dg/pr88148.f90: New testcase.

From-SVN: r266378

gcc/ChangeLog

 2018-11-22  Richard Biener  <rguenther@suse.de>
 
+	PR tree-optimization/88148
+	* tree-ssa-loop-niter.c (simplify_replace_tree): Get optional
+	valueization callback parameter and handle it.
+	* tree-ssa-loop-niter.h (simplify_replace_tree): Export.
+	* tree-ssa-sccvn.c (process_bb): Eliminate in loop niter trees.
+
+2018-11-22  Richard Biener  <rguenther@suse.de>
+
 	PR lto/87229
 	PR lto/88112
 	* lto-streamer-out.c (lto_is_streamable): Allow CALL_EXPRs

gcc/testsuite/ChangeLog

+2018-11-22  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/88148
+	* gfortran.dg/pr88148.f90: New testcase.
+
 2018-11-22  Andreas Schwab  <schwab@suse.de>
 
 	* g++.dg/lto/odr-2_0.C: Remove extra brace

gcc/tree-ssa-loop-niter.c

@@ -1919,10 +1919,14 @@ number_of_iterations_cond (struct loop *loop,
   return ret;
 }
 
-/* Substitute NEW for OLD in EXPR and fold the result.  */
+/* Substitute NEW_TREE for OLD in EXPR and fold the result.
+   If VALUEIZE is non-NULL then OLD and NEW_TREE are ignored and instead
+   all SSA names are replaced with the result of calling the VALUEIZE
+   function with the SSA name as argument.  */
 
-static tree
-simplify_replace_tree (tree expr, tree old, tree new_tree)
+tree
+simplify_replace_tree (tree expr, tree old, tree new_tree,
+		       tree (*valueize) (tree))
 {
   unsigned i, n;
   tree ret = NULL_TREE, e, se;
@@ -1931,11 +1935,20 @@ simplify_replace_tree (tree expr, tree old, tree new_tree)
     return NULL_TREE;
 
   /* Do not bother to replace constants.  */
-  if (CONSTANT_CLASS_P (old))
+  if (CONSTANT_CLASS_P (expr))
     return expr;
 
-  if (expr == old
-      || operand_equal_p (expr, old, 0))
+  if (valueize)
+    {
+      if (TREE_CODE (expr) == SSA_NAME)
+	{
+	  new_tree = valueize (expr);
+	  if (new_tree != expr)
+	    return new_tree;
+	}
+    }
+  else if (expr == old
+	   || operand_equal_p (expr, old, 0))
     return unshare_expr (new_tree);
 
   if (!EXPR_P (expr))
@@ -1945,7 +1958,7 @@ simplify_replace_tree (tree expr, tree old, tree new_tree)
   for (i = 0; i < n; i++)
     {
       e = TREE_OPERAND (expr, i);
-      se = simplify_replace_tree (e, old, new_tree);
+      se = simplify_replace_tree (e, old, new_tree, valueize);
       if (e == se)
 	continue;
 

gcc/tree-ssa-loop-niter.h

@@ -53,6 +53,7 @@ extern bool scev_probably_wraps_p (tree, tree, tree, gimple *,
 				   struct loop *, bool);
 extern void free_numbers_of_iterations_estimates (struct loop *);
 extern void free_numbers_of_iterations_estimates (function *);
+extern tree simplify_replace_tree (tree, tree, tree, tree (*)(tree) = NULL);
 extern void substitute_in_loop_info (struct loop *, tree, tree);
 
 #endif /* GCC_TREE_SSA_LOOP_NITER_H */

gcc/tree-ssa-sccvn.c

@@ -68,6 +68,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "tree-cfgcleanup.h"
 #include "tree-ssa-loop.h"
 #include "tree-scalar-evolution.h"
+#include "tree-ssa-loop-niter.h"
 #include "tree-ssa-sccvn.h"
 
 /* This algorithm is based on the SCC algorithm presented by Keith
@@ -5904,6 +5905,16 @@ process_bb (rpo_elim &avail, basic_block bb,
 	  break;
 	}
 
+  /* When we visit a loop header substitute into loop info.  */
+  if (!iterate && eliminate && bb->loop_father->header == bb)
+    {
+      /* Keep fields in sync with substitute_in_loop_info.  */
+      if (bb->loop_father->nb_iterations)
+	bb->loop_father->nb_iterations
+	  = simplify_replace_tree (bb->loop_father->nb_iterations,
+				   NULL_TREE, NULL_TREE, vn_valueize);
+    }
+
   /* Value-number all defs in the basic-block.  */
   for (gphi_iterator gsi = gsi_start_phis (bb); !gsi_end_p (gsi);
        gsi_next (&gsi))