tree-optimization/125786 - do not rewrite stmts in reassoc

We may not simply rewrite def stmts of associative operands as
they might have multiple uses.  The following appropriately
creates a new stmt instead.

	PR tree-optimization/125786
	* tree-ssa-reassoc.cc (optimize_vec_cond_expr): Create a new
	stmt instead of rewriting an existing possibly multi-use one.

	* gcc.dg/torture/pr125786.c: New testcase.

diff --git a/gcc/testsuite/gcc.dg/torture/pr125786.c b/gcc/testsuite/gcc.dg/torture/pr125786.c
new file mode 100644 (file)
index 0000000..4b432f9
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr125786.c
@@ -0,0 +1,30 @@
+/* { dg-do run } */
+
+#define length 16
+typedef int type;
+typedef type v8i64 __attribute__((vector_size(sizeof(type)*length)));
+v8i64 g6, g27;
+_Bool main_c14;
+
+__attribute__((noipa))
+static
+void f(v8i64 *a)
+{
+  for(int i =0;i<length;i++)
+    if ((*a)[i] != -1)
+      __builtin_abort();
+}
+
+int main()
+{
+  if (main_c14) goto lbl_br43;
+lbl_bf7:
+  g6 = 0 <= g27;
+  g27 = g27 <= g27;
+  g27 = g6 > g27;
+lbl_br43:
+  g6 = g6 | g27;
+  if (main_c14) goto lbl_bf7;
+  g6 = g6 * g27 == 0;
+  f(&g6);
+}

diff --git a/gcc/tree-ssa-reassoc.cc b/gcc/tree-ssa-reassoc.cc
index 4b47fb20f3a786c4b0b87f9d867b93b31efec8fe..924742878ea6680814ed108711eddf360706067d 100644 (file)
--- a/gcc/tree-ssa-reassoc.cc
+++ b/gcc/tree-ssa-reassoc.cc
@@ -4234,7 +4234,7 @@ optimize_vec_cond_expr (tree_code opcode, vec<operand_entry *> *ops)
 
   for (i = 0; i < length; ++i)
     {
-      tree elt0 = (*ops)[i]->op;
+      tree &elt0 = (*ops)[i]->op;
 
       gassign *stmt0, *vcond0;
       bool invert;
@@ -4282,11 +4282,13 @@ optimize_vec_cond_expr (tree_code opcode, vec<operand_entry *> *ops)
          gimple_stmt_iterator gsi = gsi_for_stmt (vcond0);
          tree exp = force_gimple_operand_gsi (&gsi, comb, true, NULL_TREE,
                                               true, GSI_SAME_STMT);
-         if (invert)
-           swap_ssa_operands (vcond0, gimple_assign_rhs2_ptr (vcond0),
-                              gimple_assign_rhs3_ptr (vcond0));
-         gimple_assign_set_rhs1 (vcond0, exp);
-         update_stmt (vcond0);
+         tree res = gimple_build (&gsi, true, GSI_SAME_STMT, UNKNOWN_LOCATION,
+                                  VEC_COND_EXPR, TREE_TYPE (elt0), exp,
+                                  constant_boolean_node (true,
+                                                         TREE_TYPE (elt0)),
+                                  constant_boolean_node (false,
+                                                         TREE_TYPE (elt0)));
+         elt0 = res;
 
          elt1 = error_mark_node;
          any_changes = true;