[PATCH] Fix sibcall argument overlap checking if pretend_args_size (PR target/52129)

[Jakub Jelinek]

Hi!

The attached testcase is miscompiled on arm*, by doing a sibcall when setup
of one argument overwrites incoming arguments used to setup parameters in
later insns.
The reason why
mem_overlaps_already_clobbered_arg_p/check_sibcall_argument_overlap
fails to detect is that the caller has non-zero
crtl->args.pretend_args_size, and in that case the base:
      /* The argument block when performing a sibling call is the
         incoming argument block.  */
      if (pass == 0)
        {
          argblock = crtl->args.internal_arg_pointer;
          argblock
#ifdef STACK_GROWS_DOWNWARD
            = plus_constant (argblock, crtl->args.pretend_args_size);
#else
            = plus_constant (argblock, -crtl->args.pretend_args_size);
#endif
          stored_args_map = sbitmap_alloc (args_size.constant);
          sbitmap_zero (stored_args_map);
        }
apparently isn't virtual-incoming-rtx, but that plus pretend_args_size
(8 in this case).  When we store bits into stored_args_map sbitmap,
we use arg->locate.slot_offset.constant based values (or something different
for ARGS_GROW_DOWNWARD, but when mem_overlaps_already_clobbered_arg_p is
testing those bits, it uses just virtual-incoming-rtx offsets (or something
different for ARGS_GROW_DOWNWARD).  This patch fixes it by adjusting the
virtual-incoming-rtx relative offset to be actually argblock relative
offset.

Bootstrapped/regtested on x86_64-linux and i686-linux and tested on the
testcase on arm cross.  Ok for trunk?

2012-02-06  Jakub Jelinek  <ja...@redhat.com>

        PR target/52129
        * calls.c (mem_overlaps_already_clobbered_arg_p): If val is
        CONST_INT_P, subtract resp. add crtl->args.pretend_args_size to it.

        * gcc.c-torture/execute/pr52129.c: New test.

--- gcc/calls.c.jj      2012-02-01 14:44:27.000000000 +0100
+++ gcc/calls.c 2012-02-06 10:19:12.112132905 +0100
@@ -1808,6 +1808,11 @@ mem_overlaps_already_clobbered_arg_p (rt
     return true;
   else
     i = INTVAL (val);
+#ifdef STACK_GROWS_DOWNWARD
+  i -= crtl->args.pretend_args_size;
+#else
+  i += crtl->args.pretend_args_size;
+#endif
 
 #ifdef ARGS_GROW_DOWNWARD
   i = -i - size;
--- gcc/testsuite/gcc.c-torture/execute/pr52129.c.jj    2012-02-06 
10:27:50.988876791 +0100
+++ gcc/testsuite/gcc.c-torture/execute/pr52129.c       2012-02-06 
10:25:26.000000000 +0100
@@ -0,0 +1,28 @@
+/* PR target/52129 */
+
+extern void abort (void);
+struct S { void *p; unsigned int q; };
+struct T { char a[64]; char b[64]; } t;
+
+__attribute__((noinline, noclone)) int
+foo (void *x, struct S s, void *y, void *z)
+{
+  if (x != &t.a[2] || s.p != &t.b[5] || s.q != 27 || y != &t.a[17] || z != 
&t.b[17])
+    abort ();
+  return 29;
+}
+
+__attribute__((noinline, noclone)) int
+bar (void *x, void *y, void *z, struct S s, int t, struct T *u)
+{
+  return foo (x, s, &u->a[t], &u->b[t]);
+}
+
+int
+main ()
+{
+  struct S s = { &t.b[5], 27 };
+  if (bar (&t.a[2], (void *) 0, (void *) 0, s, 17, &t) != 29)
+    abort ();
+  return 0;
+}

        Jakub