2016-05-12 Richard Biener <rguenther@suse.de>

	PR tree-optimization/71059
	* tree-ssa-pre.c (phi_translate_1): Fully fold translated
	nary before looking up or entering the expression into the VN
	hashes.
	* tree-ssa-sccvn.c (vn_nary_build_or_lookup): Fix comment typo.
	Make sure to re-use NARYs without result as inserted by
	phi-translation.

	* gcc.dg/torture/pr71059.c: New testcase.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@236175 138bc75d-0d04-0410-961f-82ee72b054a4

5 files changed, 48 insertions, 9 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index ddea24baf0d..4edaf4ba2a4 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,15 @@
 2016-05-12  Richard Biener  <rguenther@suse.de>
 
+	PR tree-optimization/71059
+	* tree-ssa-pre.c (phi_translate_1): Fully fold translated
+	nary before looking up or entering the expression into the VN
+	hashes.
+	* tree-ssa-sccvn.c (vn_nary_build_or_lookup): Fix comment typo.
+	Make sure to re-use NARYs without result as inserted by
+	phi-translation.
+
+2016-05-12  Richard Biener  <rguenther@suse.de>
+
 	PR tree-optimization/71062
 	* tree-ssa-alias.h (struct pt_solution): Add vars_contains_restrict
 	field.
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 6dca22fd182..5ecb1a331e5 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,5 +1,10 @@
 2016-05-12  Richard Biener  <rguenther@suse.de>
 
+	PR tree-optimization/71059
+	* gcc.dg/torture/pr71059.c: New testcase.
+
+2016-05-12  Richard Biener  <rguenther@suse.de>
+
 	PR tree-optimization/71062
 	* gcc.dg/torture/pr71062.c: New testcase.
 
diff --git a/gcc/testsuite/gcc.dg/torture/pr71059.c b/gcc/testsuite/gcc.dg/torture/pr71059.c
new file mode 100644
index 00000000000..7c0ab7f1493
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr71059.c
@@ -0,0 +1,15 @@
+/* { dg-do compile } */
+
+short a, c;
+union {
+    unsigned f0;
+    unsigned short f1;
+} b;
+volatile int d;
+short fn1(short p1) { return p1 + a; }
+void fn2()
+{
+  b.f0 = 0;
+  for (;; b.f0 = fn1(b.f0))
+    (c && b.f1) || d;
+}
diff --git a/gcc/tree-ssa-pre.c b/gcc/tree-ssa-pre.c
index 4a771d3b0be..3ce87d9d23f 100644
--- a/gcc/tree-ssa-pre.c
+++ b/gcc/tree-ssa-pre.c
@@ -1464,6 +1464,12 @@ phi_translate_1 (pre_expr expr, bitmap_set_t set1, bitmap_set_t set2,
 	    pre_expr constant;
 	    unsigned int new_val_id;
 
+	    PRE_EXPR_NARY (expr) = newnary;
+	    constant = fully_constant_expression (expr);
+	    PRE_EXPR_NARY (expr) = nary;
+	    if (constant != expr)
+	      return constant;
+
 	    tree result = vn_nary_op_lookup_pieces (newnary->length,
 						    newnary->opcode,
 						    newnary->type,
@@ -1478,10 +1484,6 @@ phi_translate_1 (pre_expr expr, bitmap_set_t set1, bitmap_set_t set2,
 	    if (nary)
 	      {
 		PRE_EXPR_NARY (expr) = nary;
-		constant = fully_constant_expression (expr);
-		if (constant != expr)
-		  return constant;
-
 		new_val_id = nary->value_id;
 		get_or_alloc_expression_id (expr);
 	      }
@@ -1495,9 +1497,6 @@ phi_translate_1 (pre_expr expr, bitmap_set_t set1, bitmap_set_t set2,
 						 &newnary->op[0],
 						 result, new_val_id);
 		PRE_EXPR_NARY (expr) = nary;
-		constant = fully_constant_expression (expr);
-		if (constant != expr)
-		  return constant;
 		get_or_alloc_expression_id (expr);
 	      }
 	    add_to_value (new_val_id, expr);
diff --git a/gcc/tree-ssa-sccvn.c b/gcc/tree-ssa-sccvn.c
index 1567fb96afb..730db04ff8b 100644
--- a/gcc/tree-ssa-sccvn.c
+++ b/gcc/tree-ssa-sccvn.c
@@ -1632,7 +1632,7 @@ vn_nary_build_or_lookup (code_helper rcode, tree type, tree *ops)
 {
   tree result = NULL_TREE;
   /* We will be creating a value number for
-       ROCDE (OPS...).
+       RCODE (OPS...).
      So first simplify and lookup this expression to see if it
      is already available.  */
   mprts_hook = vn_lookup_simplify_result;
@@ -1682,6 +1682,16 @@ vn_nary_build_or_lookup (code_helper rcode, tree type, tree *ops)
       gimple_seq_add_stmt_without_update (&VN_INFO (result)->expr,
 					  new_stmt);
       VN_INFO (result)->needs_insertion = true;
+      /* ???  PRE phi-translation inserts NARYs without corresponding
+         SSA name result.  Re-use those but set their result according
+	 to the stmt we just built.  */
+      vn_nary_op_t nary = NULL;
+      vn_nary_op_lookup_stmt (new_stmt, &nary);
+      if (nary)
+	{
+	  gcc_assert (nary->result == NULL_TREE);
+	  nary->result = gimple_assign_lhs (new_stmt);
+	}
       /* As all "inserted" statements are singleton SCCs, insert
 	 to the valid table.  This is strictly needed to
 	 avoid re-generating new value SSA_NAMEs for the same
@@ -1689,7 +1699,7 @@ vn_nary_build_or_lookup (code_helper rcode, tree type, tree *ops)
 	 optimistic table gets cleared after each iteration).
 	 We do not need to insert into the optimistic table, as
 	 lookups there will fall back to the valid table.  */
-      if (current_info == optimistic_info)
+      else if (current_info == optimistic_info)
 	{
 	  current_info = valid_info;
 	  vn_nary_op_insert_stmt (new_stmt, result);