i386.c (ix86_compute_frame_layout): Do add bottom alignment for alloca.

        * config/i386/i386.c (ix86_compute_frame_layout): Do add bottom
        alignment for alloca.

	* gcc.c-torture/execute/alloca-1.c: New.

From-SVN: r54018

gcc/ChangeLog

 2002-05-29  Richard Henderson  <rth@redhat.com>
 
+	* config/i386/i386.c (ix86_compute_frame_layout): Do add bottom
+	alignment for alloca.
+
+2002-05-29  Richard Henderson  <rth@redhat.com>
+
 	* config/i386/i386.c (output_pic_addr_const): Lowercase rip.
 	(print_operand_address): Only add rip for symbolic addresses
 	for which we do not have another relocation type.

gcc/config/i386/i386.c

@@ -4148,8 +4148,9 @@ ix86_compute_frame_layout (frame)
   else
     frame->outgoing_arguments_size = 0;
 
-  /* Align stack boundary.  Only needed if we're calling another function.  */
-  if (!current_function_is_leaf)
+  /* Align stack boundary.  Only needed if we're calling another function
+     or using alloca.  */
+  if (!current_function_is_leaf || current_function_calls_alloca)
     frame->padding2 = ((offset + preferred_alignment - 1)
 		       & -preferred_alignment) - offset;
   else

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

+/* Verify that alloca storage is sufficiently aligned.  */
+/* ??? May fail if BIGGEST_ALIGNMENT > STACK_BOUNDARY.  Which, I guess
+   can only happen on !STRICT_ALIGNMENT targets.  */
+
+typedef __SIZE_TYPE__ size_t;
+
+struct dummy { int x __attribute__((aligned)); };
+#define BIGGEST_ALIGNMENT __alignof__(struct dummy)
+
+_Bool foo(void)
+{
+  char *p = __builtin_alloca(32);
+  return ((size_t)p & (BIGGEST_ALIGNMENT - 1)) == 0;
+}
+
+int main()
+{
+  if (!foo())
+    abort ();
+  return 0;
+}