gcc/

2010-08-26  H.J. Lu  <hongjiu.lu@intel.com>

	PR middle-end/45234
	* calls.c (expand_call): Make sure that all variable sized
	adjustments are multiple of preferred stack boundary after
	stack alignment.

gcc/testsuite/

2010-08-26  H.J. Lu  <hongjiu.lu@intel.com>

	PR middle-end/45234
	* gcc.dg/torture/stackalign/alloca-5.c: New.

diff --git a/gcc/calls.c b/gcc/calls.c
index cd0d9c5..87b5808 100644
--- a/gcc/calls.c
+++ b/gcc/calls.c
@@ -2377,6 +2377,19 @@ expand_call (tree exp, rtx target, int ignore)
 
   preferred_unit_stack_boundary = preferred_stack_boundary / BITS_PER_UNIT;
 
+  if (SUPPORTS_STACK_ALIGNMENT)
+    {
+      /* All variable sized adjustments must be multiple of preferred
+	 stack boundary.  Stack alignment may change preferred stack
+	 boundary after variable sized adjustments have been made.  We
+	 need to compensate it here.  */
+      unsigned HOST_WIDE_INT delta
+	= ((stack_pointer_delta - pending_stack_adjust)
+	   % preferred_unit_stack_boundary);
+      if (delta)
+	anti_adjust_stack (GEN_INT (preferred_unit_stack_boundary - delta));
+    }
+
   /* We want to make two insn chains; one for a sibling call, the other
      for a normal call.  We will select one of the two chains after
      initial RTL generation is complete.  */
--- /dev/null	2010-07-23 13:04:30.193381062 -0700
+++ gcc/gcc/testsuite/gcc.dg/torture/stackalign/alloca-5.c	2010-08-10 06:29:57.308629935 -0700
@@ -0,0 +1,32 @@
+/* PR middle-end/45234 */
+/* { dg-do run { target { { i?86-*-* x86_64-*-* } && ilp32 } } } */
+/* { dg-options "-m32 -mincoming-stack-boundary=2 -mpreferred-stack-boundary=2" } */
+
+#include "check.h"
+
+void
+__attribute__ ((noinline))
+bar (__float128 f)
+{
+  check (&f, __alignof__(f));
+}
+
+int
+main (void)
+{
+  char *p = __builtin_alloca (6);
+
+  bar (0);
+
+  __builtin_strncpy (p, "good", 5);
+  if (__builtin_strncmp (p, "good", 5) != 0)
+    {
+#ifdef DEBUG
+      p[size] = '\0';
+      printf ("Failed: %s != good\n", p);
+#endif
+     abort ();
+    }
+
+  return 0;
+}