re PR middle-end/71269 (segfault while compiling sqlite)

gcc/testsuite/ChangeLog:

2016-05-30  Kugan Vivekanandarajah  <kuganv@linaro.org>

	PR middle-end/71269
	PR middle-end/71292
	* gcc.dg/tree-ssa/pr71269.c: New test.
	* gcc.dg/tree-ssa/pr71292.c: New test.

gcc/ChangeLog:

2016-05-30  Kugan Vivekanandarajah  <kuganv@linaro.org>

	PR middle-end/71269
	PR middle-end/71252
	* tree-ssa-reassoc.c (insert_stmt_before_use): Use find_insert_point so
	that inserted stmt will not dominate stmts that defines its operand.
	(rewrite_expr_tree): Add stmt_to_insert before adding the use stmt.
	(rewrite_expr_tree_parallel): Likewise.

From-SVN: r236876

1 files changed, 37 insertions, 34 deletions

diff --git a/gcc/tree-ssa-reassoc.c b/gcc/tree-ssa-reassoc.c
index d13be29..9c06ca0 100644
--- a/gcc/tree-ssa-reassoc.c
+++ b/gcc/tree-ssa-reassoc.c
@@ -1777,16 +1777,6 @@ eliminate_redundant_comparison (enum tree_code opcode,
   return false;
 }
 
-/* If the stmt that defines operand has to be inserted, insert it
-   before the use.  */
-static void
-insert_stmt_before_use (gimple *stmt, gimple *stmt_to_insert)
-{
-  gimple_stmt_iterator gsi = gsi_for_stmt (stmt);
-  gimple_set_uid (stmt_to_insert, gimple_uid (stmt));
-  gsi_insert_before (&gsi, stmt_to_insert, GSI_NEW_STMT);
-}
-
 
 /* Transform repeated addition of same values into multiply with
    constant.  */
@@ -3787,6 +3777,29 @@ find_insert_point (gimple *stmt, tree rhs1, tree rhs2)
   return stmt;
 }
 
+/* If the stmt that defines operand has to be inserted, insert it
+   before the use.  */
+static void
+insert_stmt_before_use (gimple *stmt, gimple *stmt_to_insert)
+{
+  gcc_assert (is_gimple_assign (stmt_to_insert));
+  tree rhs1 = gimple_assign_rhs1 (stmt_to_insert);
+  tree rhs2 = gimple_assign_rhs2 (stmt_to_insert);
+  gimple *insert_point = find_insert_point (stmt, rhs1, rhs2);
+  gimple_stmt_iterator gsi = gsi_for_stmt (insert_point);
+  gimple_set_uid (stmt_to_insert, gimple_uid (insert_point));
+
+  /* If the insert point is not stmt, then insert_point would be
+     the point where operand rhs1 or rhs2 is defined. In this case,
+     stmt_to_insert has to be inserted afterwards. This would
+     only happen when the stmt insertion point is flexible. */
+  if (stmt == insert_point)
+    gsi_insert_before (&gsi, stmt_to_insert, GSI_NEW_STMT);
+  else
+    insert_stmt_after (stmt_to_insert, insert_point);
+}
+
+
 /* Recursively rewrite our linearized statements so that the operators
    match those in OPS[OPINDEX], putting the computation in rank
    order.  Return new lhs.  */
@@ -3823,6 +3836,12 @@ rewrite_expr_tree (gimple *stmt, unsigned int opindex,
 	      print_gimple_stmt (dump_file, stmt, 0, 0);
 	    }
 
+	  /* If the stmt that defines operand has to be inserted, insert it
+	     before the use.  */
+	  if (oe1->stmt_to_insert)
+	    insert_stmt_before_use (stmt, oe1->stmt_to_insert);
+	  if (oe2->stmt_to_insert)
+	    insert_stmt_before_use (stmt, oe2->stmt_to_insert);
 	  /* Even when changed is false, reassociation could have e.g. removed
 	     some redundant operations, so unless we are just swapping the
 	     arguments or unless there is no change at all (then we just
@@ -3831,12 +3850,6 @@ rewrite_expr_tree (gimple *stmt, unsigned int opindex,
 	    {
 	      gimple *insert_point
 		= find_insert_point (stmt, oe1->op, oe2->op);
-	      /* If the stmt that defines operand has to be inserted, insert it
-		 before the use.  */
-	      if (oe1->stmt_to_insert)
-		insert_stmt_before_use (stmt, oe1->stmt_to_insert);
-	      if (oe2->stmt_to_insert)
-		insert_stmt_before_use (stmt, oe2->stmt_to_insert);
 	      lhs = make_ssa_name (TREE_TYPE (lhs));
 	      stmt
 		= gimple_build_assign (lhs, gimple_assign_rhs_code (stmt),
@@ -3852,12 +3865,6 @@ rewrite_expr_tree (gimple *stmt, unsigned int opindex,
 	    {
 	      gcc_checking_assert (find_insert_point (stmt, oe1->op, oe2->op)
 				   == stmt);
-	      /* If the stmt that defines operand has to be inserted, insert it
-		 before the use.  */
-	      if (oe1->stmt_to_insert)
-		insert_stmt_before_use (stmt, oe1->stmt_to_insert);
-	      if (oe2->stmt_to_insert)
-		insert_stmt_before_use (stmt, oe2->stmt_to_insert);
 	      gimple_assign_set_rhs1 (stmt, oe1->op);
 	      gimple_assign_set_rhs2 (stmt, oe2->op);
 	      update_stmt (stmt);
@@ -4097,16 +4104,18 @@ rewrite_expr_tree_parallel (gassign *stmt, int width,
 	  print_gimple_stmt (dump_file, stmts[i], 0, 0);
 	}
 
+      /* If the stmt that defines operand has to be inserted, insert it
+	 before the use.  */
+      if (stmt1)
+	insert_stmt_before_use (stmts[i], stmt1);
+      if (stmt2)
+	insert_stmt_before_use (stmts[i], stmt2);
+      stmt1 = stmt2 = NULL;
+
       /* We keep original statement only for the last one.  All
 	 others are recreated.  */
       if (i == stmt_num - 1)
 	{
-	  /* If the stmt that defines operand has to be inserted, insert it
-	     before the use.  */
-	  if (stmt1)
-	    insert_stmt_before_use (stmts[i], stmt1);
-	  if (stmt2)
-	    insert_stmt_before_use (stmts[i], stmt2);
 	  gimple_assign_set_rhs1 (stmts[i], op1);
 	  gimple_assign_set_rhs2 (stmts[i], op2);
 	  update_stmt (stmts[i]);
@@ -4114,12 +4123,6 @@ rewrite_expr_tree_parallel (gassign *stmt, int width,
       else
 	{
 	  stmts[i] = build_and_add_sum (TREE_TYPE (last_rhs1), op1, op2, opcode);
-	  /* If the stmt that defines operand has to be inserted, insert it
-	     before new build_and_add stmt after it is created.  */
-	  if (stmt1)
-	    insert_stmt_before_use (stmts[i], stmt1);
-	  if (stmt2)
-	    insert_stmt_before_use (stmts[i], stmt2);
 	}
       if (dump_file && (dump_flags & TDF_DETAILS))
 	{