re PR rtl-optimization/16968 (loop optimizer miscompilation)

PR rtl-optimization/16968
	* loop.c (scan_loop): Stop scanning the loop for movable
	insns as soon as an optimization barrier is encountered.

From-SVN: r92348

gcc/ChangeLog

@@ -1,3 +1,9 @@
+2004-12-18  Eric Botcazou  <ebotcazou@libertysurf.fr>
+
+	PR rtl-optimization/16968
+	* loop.c (scan_loop): Stop scanning the loop for movable
+	insns as soon as an optimization barrier is encountered.
+
 2004-12-17  Zack Weinberg  <zack@codesourcery.com>
 
 	PR 18897

gcc/loop.c

@@ -1119,6 +1119,9 @@ scan_loop (struct loop *loop, int flags)
 	in_libcall--;
       if (NONJUMP_INSN_P (p))
 	{
+	  /* Do not scan past an optimization barrier.  */
+	  if (GET_CODE (PATTERN (p)) == ASM_INPUT)
+	    break;
 	  temp = find_reg_note (p, REG_LIBCALL, NULL_RTX);
 	  if (temp)
 	    in_libcall++;

gcc/testsuite/ChangeLog

@@ -1,3 +1,7 @@
+2004-12-18  Jakub Jelinek  <jakub@redhat.com>
+
+	* gcc.c-torture/execute/20041218-1.c: New test.
+
 2004-12-17  Diego Novillo  <dnovillo@redhat.com>
 
 	* gcc.dg/pr18501.c: New test.

gcc/testsuite/gcc.c-torture/execute/20041218-1.c

@@ -0,0 +1,117 @@
+/* PR rtl-optimization/16968 */
+/* Testcase by Jakub Jelinek  <jakub@redhat.com> */
+
+struct T
+{
+  unsigned int b, c, *d;
+  unsigned char e;
+};
+struct S
+{
+  unsigned int a;
+  struct T f;
+};
+struct U
+{
+  struct S g, h;
+};
+struct V
+{
+  unsigned int i;
+  struct U j;
+};
+
+extern void exit (int);
+extern void abort (void);
+
+void *
+dummy1 (void *x)
+{
+  return "";
+}
+
+void *
+dummy2 (void *x, void *y)
+{
+  exit (0);
+}
+
+struct V *
+baz (unsigned int x)
+{
+  static struct V v;
+  __builtin_memset (&v, 0x55, sizeof (v));
+  return &v;
+}
+
+int
+check (void *x, struct S *y)
+{
+  if (y->a || y->f.b || y->f.c || y->f.d || y->f.e)
+    abort ();
+  return 1;
+}
+
+static struct V *
+bar (unsigned int x, void *y)
+{
+  const struct T t = { 0, 0, (void *) 0, 0 };
+  struct V *u;
+  void *v;
+  v = dummy1 (y);
+  if (!v)
+    return (void *) 0;
+
+  u = baz (sizeof (struct V));
+  u->i = x;
+  u->j.g.a = 0;
+  u->j.g.f = t;
+  u->j.h.a = 0;
+  u->j.h.f = t;
+
+  if (!check (v, &u->j.g) || !check (v, &u->j.h))
+    return (void *) 0;
+  return u;
+}
+
+int
+foo (unsigned int *x, unsigned int y, void **z)
+{
+  void *v;
+  unsigned int i, j;
+
+  *z = v = (void *) 0;
+
+  for (i = 0; i < y; i++)
+    {
+      struct V *c;
+
+      j = *x;
+
+      switch (j)
+	{
+	case 1:
+	  c = bar (j, x);
+	  break;
+	default:
+	  c = 0;
+	  break;
+	}
+      if (c)
+	v = dummy2 (v, c);
+      else
+        return 1;
+    }
+
+  *z = v;
+  return 0;
+}
+
+int
+main (void)
+{
+  unsigned int one = 1;
+  void *p;
+  foo (&one, 1, &p);
+  abort ();
+}