re PR middle-end/7847 (pragma pack / attribute(packed): unaligned access to packed structure)

	PR middle-end/7847
	* expr.c (expand_expr) [normal_inner_ref]: When 'offset' is non-zero,
	do not recheck that 'op0' is a MEM.  Move comment.  When testing for
	unaligned objects, take also into account the alignment of 'op0' and
	'mode1' if 'op0' is a MEM.

From-SVN: r74092

gcc/ChangeLog

+2003-12-01  Eric Botcazou  <ebotcazou@libertysurf.fr>
+
+	PR middle-end/7847
+	* expr.c (expand_expr) [normal_inner_ref]: When 'offset' is non-zero,
+	do not recheck that 'op0' is a MEM.  Move comment.  When testing for
+	unaligned objects, take also into account the alignment of 'op0' and
+	'mode1' if 'op0' is a MEM.
+
 2003-12-01 Gabriel Dos Reis <gdr@integrable-solutions.net>
 
 	* doc/c-tree.texi (Function Bodies): Update HANDLER documentation.

gcc/expr.c

@@ -7153,10 +7153,9 @@ expand_expr (tree exp, rtx target, enum machine_mode tmode,
 	      offset_rtx = convert_to_mode (ptr_mode, offset_rtx, 0);
 #endif
 
-	    /* A constant address in OP0 can have VOIDmode, we must not try
-	       to call force_reg for that case.  Avoid that case.  */
-	    if (GET_CODE (op0) == MEM
-		&& GET_MODE (op0) == BLKmode
+	    if (GET_MODE (op0) == BLKmode
+		/* A constant address in OP0 can have VOIDmode, we must
+		   not try to call force_reg in that case.  */
 		&& GET_MODE (XEXP (op0, 0)) != VOIDmode
 		&& bitsize != 0
 		&& (bitpos % bitsize) == 0
@@ -7213,7 +7212,10 @@ expand_expr (tree exp, rtx target, enum machine_mode tmode,
 	       fetch it as a bit field.  */
 	    || (mode1 != BLKmode
 		&& (((TYPE_ALIGN (TREE_TYPE (tem)) < GET_MODE_ALIGNMENT (mode)
-		      || (bitpos % GET_MODE_ALIGNMENT (mode) != 0))
+		      || (bitpos % GET_MODE_ALIGNMENT (mode) != 0)
+		      || (GET_CODE (op0) == MEM
+			  && (MEM_ALIGN (op0) < GET_MODE_ALIGNMENT (mode1)
+			      || (bitpos % GET_MODE_ALIGNMENT (mode1) != 0))))
 		     && ((modifier == EXPAND_CONST_ADDRESS
 			  || modifier == EXPAND_INITIALIZER)
 			 ? STRICT_ALIGNMENT

gcc/testsuite/ChangeLog

+2003-12-01  Eric Botcazou  <ebotcazou@libertysurf.fr>
+
+	* gcc.dg/unaligned-1.c: New test.
+
 2003-11-30  Mark Mitchell  <mark@codesourcery.com>
 
 	PR c++/9849

gcc/testsuite/gcc.dg/unaligned-1.c

+/* PR middle-end/7847 */
+/* Originator: <jk@tools.de> */
+/* { dg-do run } */
+
+/* This used to fail on SPARC at runtime because of
+   an unaligned memory access.  */
+
+typedef char int8_t;
+typedef short int16_t;
+typedef int int32_t;
+typedef unsigned char uint8_t;
+typedef unsigned short uint16_t;
+typedef unsigned int uint32_t;
+
+typedef struct {
+    uint32_t address;
+    uint16_t size;
+} __attribute__ ((packed)) sml_agl_data_t;
+
+typedef struct {
+  sml_agl_data_t data[9];
+} __attribute__ ((packed)) sml_agli_t;
+
+typedef struct {
+  sml_agli_t sml_agli;
+} __attribute__ ((packed)) dsi_t;
+
+typedef struct {
+  int a;
+  dsi_t dsi_pack;
+} dvd_priv_t;
+
+int dvd_read_sector(dvd_priv_t *d, unsigned char* data)
+{
+  int i, skip=0;
+
+  for (i=0; i < 9; i++)
+    if ((skip=d->dsi_pack.sml_agli.data[i].address) != 0)
+      break;
+
+  return skip;
+}
+
+int main(void)
+{
+  static dvd_priv_t dvd_priv;
+  dvd_read_sector(&dvd_priv, 0);
+  return 0;
+}