re PR rtl-optimization/89634 (gmp-ecm miscompilation on s390x with -march=zEC12 -m64 -O2)

	PR rtl-optimization/89634
	* cfgcleanup.c (thread_jump): Punt if registers mentioned in cond1
	are modified in BB_END (e->src) instruction.

	* gcc.c-torture/execute/pr89634.c: New test.

From-SVN: r269522

gcc/ChangeLog

+2019-03-09  Jakub Jelinek  <jakub@redhat.com>
+
+	PR rtl-optimization/89634
+	* cfgcleanup.c (thread_jump): Punt if registers mentioned in cond1
+	are modified in BB_END (e->src) instruction.
+
 2019-03-08  David Malcolm  <dmalcolm@redhat.com>
 
 	PR target/79926

gcc/cfgcleanup.c

@@ -308,6 +308,11 @@ thread_jump (edge e, basic_block b)
       || !rtx_equal_p (XEXP (cond1, 1), XEXP (cond2, 1)))
     return NULL;
 
+  /* Punt if BB_END (e->src) is doloop-like conditional jump that modifies
+     the registers used in cond1.  */
+  if (modified_in_p (cond1, BB_END (e->src)))
+    return NULL;
+
   /* Short circuit cases where block B contains some side effects, as we can't
      safely bypass it.  */
   for (insn = NEXT_INSN (BB_HEAD (b)); insn != NEXT_INSN (BB_END (b));

gcc/testsuite/ChangeLog

+2019-03-09  Jakub Jelinek  <jakub@redhat.com>
+
+	PR rtl-optimization/89634
+	* gcc.c-torture/execute/pr89634.c: New test.
+
 2019-03-08  Jakub Jelinek  <jakub@redhat.com>
 
 	PR c/85870

gcc/testsuite/gcc.c-torture/execute/pr89634.c

+/* PR rtl-optimization/89634 */
+
+static unsigned long *
+foo (unsigned long *x)
+{
+  return x + (1 + *x);
+}
+
+__attribute__((noipa)) unsigned long
+bar (unsigned long *x)
+{
+  unsigned long c, d = 1, e, *f, g, h = 0, i;
+  for (e = *x - 1; e > 0; e--)
+    {
+      f = foo (x + 1);
+      for (i = 1; i < e; i++)
+	f = foo (f);
+      c = *f;
+      if (c == 2)
+	d *= 2;
+      else
+	{
+	  i = (c - 1) / 2 - 1;
+	  g = (2 * i + 1) * (d + 1) + (2 * d + 1);
+	  if (g > h)
+	    h = g;
+	  d *= c;
+	}
+    }
+  return h;
+}
+
+int
+main ()
+{
+  unsigned long a[18] = { 4, 2, -200, 200, 2, -400, 400, 3, -600, 0, 600, 5, -100, -66, 0, 66, 100, __LONG_MAX__ / 8 + 1 };
+  if (bar (a) != 17)
+    __builtin_abort ();
+  return 0;
+}