[PATCH] Avoid (X / Y) == 0 -> X < Y match.pd opt for complex types (PR middle-end/86123)

[Jakub Jelinek]

Hi!

We allow only equality/non-equality comparisons of complex numbers, so
introducing less than or greater or equal than comparison for them from
non-equality ones + division is a bad idea; e.g. the expansion will not
handle those.

Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk/8.2?

2018-06-15  Jakub Jelinek  <ja...@redhat.com>

        PR middle-end/86123
        * match.pd ((X / Y) == 0 -> X < Y): Don't transform complex divisions.
        Fix up comment formatting.

        * gcc.c-torture/compile/pr86123.c: New test.

--- gcc/match.pd.jj     2018-06-14 21:07:15.785350884 +0200
+++ gcc/match.pd        2018-06-15 08:14:56.134977947 +0200
@@ -1462,14 +1462,15 @@ (define_operator_list COND_BINARY
    (op @1 { build_zero_cst (TREE_TYPE (@1)); }))))
 
 /* Transform:
- * (X / Y) == 0 -> X < Y if X, Y are unsigned.
- * (X / Y) != 0 -> X >= Y, if X, Y are unsigned.
- */
+   (X / Y) == 0 -> X < Y if X, Y are unsigned.
+   (X / Y) != 0 -> X >= Y, if X, Y are unsigned.  */
 (for cmp (eq ne)
      ocmp (lt ge)
  (simplify
   (cmp (trunc_div @0 @1) integer_zerop)
   (if (TYPE_UNSIGNED (TREE_TYPE (@0))
+       /* Complex ==/!= is allowed, but not </>=.  */
+       && TREE_CODE (TREE_TYPE (@0)) != COMPLEX_TYPE
        && (VECTOR_TYPE_P (type) || !VECTOR_TYPE_P (TREE_TYPE (@0))))
    (ocmp @0 @1))))
 
--- gcc/testsuite/gcc.c-torture/compile/pr86123.c.jj    2018-06-15 
08:27:24.851654403 +0200
+++ gcc/testsuite/gcc.c-torture/compile/pr86123.c       2018-06-15 
08:27:11.632645612 +0200
@@ -0,0 +1,17 @@
+/* PR middle-end/86123 */
+
+int
+foo (_Complex unsigned x, _Complex unsigned y)
+{
+  _Complex unsigned t1 = x / y;
+  int t2 = (t1 != 0);
+  return t2;
+}
+
+int
+bar (_Complex unsigned x, _Complex unsigned y)
+{
+  _Complex unsigned t1 = x / y;
+  int t2 = (t1 == 0);
+  return t2;
+}

        Jakub