re PR middle-end/26565 (Unaligned accesses with __attribute__(packed) and memcpy)

2006-03-10  Richard Guenther  <rguenther@suse.de>

	PR middle-end/26565
	* builtins.c (get_pointer_alignment): Handle component
	references for field alignment.

	* gcc.dg/torture/pr26565.c: New testcase.

From-SVN: r111934

gcc/ChangeLog

+2006-03-10  Richard Guenther  <rguenther@suse.de>
+
+	PR middle-end/26565
+	* builtins.c (get_pointer_alignment): Handle component
+	references for field alignment.
+
 2006-03-10  J"orn Rennecke <joern.rennecke@st.com>
 
 	* config.gcc (sh*-superh-elf, sh*elf (newlib)): Use newlib.h

gcc/builtins.c

@@ -275,15 +275,21 @@ get_pointer_alignment (tree exp, unsigned int max_align)
 	case ADDR_EXPR:
 	  /* See what we are pointing at and look at its alignment.  */
 	  exp = TREE_OPERAND (exp, 0);
+	  while (handled_component_p (exp))
+	    {
+	      if (TREE_CODE (exp) == COMPONENT_REF)
+		align = MIN (align, DECL_ALIGN (TREE_OPERAND (exp, 1)));
+	      exp = TREE_OPERAND (exp, 0);
+	    }
 	  if (TREE_CODE (exp) == FUNCTION_DECL)
-	    align = FUNCTION_BOUNDARY;
+	    align = MIN (align, FUNCTION_BOUNDARY);
 	  else if (DECL_P (exp))
-	    align = DECL_ALIGN (exp);
+	    align = MIN (align, DECL_ALIGN (exp));
 #ifdef CONSTANT_ALIGNMENT
 	  else if (CONSTANT_CLASS_P (exp))
-	    align = CONSTANT_ALIGNMENT (exp, align);
+	    align = MIN (align, (unsigned)CONSTANT_ALIGNMENT (exp, align));
 #endif
-	  return MIN (align, max_align);
+	  return align;
 
 	default:
 	  return align;

gcc/testsuite/ChangeLog

+2006-03-10  Richard Guenther  <rguenther@suse.de>
+
+	PR middle-end/26565
+	* gcc.dg/torture/pr26565.c: New testcase.
+
 2006-03-09  Jerry DeLisle  <jvdelisle@gcc.gnu.org>
 
 	PR libgfortran/26499

gcc/testsuite/gcc.dg/torture/pr26565.c

+/* { dg-do run } */
+
+void *memcpy(void *dest, const void *src, __SIZE_TYPE__ n);
+
+struct timeval {
+    long tv_sec;
+};
+
+struct outdata {
+    long align;
+    char seq;
+    struct timeval tv __attribute__((packed));
+};
+
+void send_probe(struct outdata *outdata, struct timeval *tp) __attribute__((noinline));
+void send_probe(struct outdata *outdata, struct timeval *tp)
+{
+    memcpy(&outdata->tv, tp, sizeof outdata->tv);
+}
+
+struct timeval t;
+struct outdata outdata;
+
+int main()
+{
+  send_probe(&outdata, &t);
+  return 0;
+}