expr.c (expand_assignment): Handle misaligned scalar writes to memory through top-level MEM_REFs by calling...

2012-03-13  Martin Jambor  <mjambor@suse.cz>

	* expr.c (expand_assignment): Handle misaligned scalar writes to
	memory through top-level MEM_REFs by calling store_bit_field.

	* testsuite/gcc.dg/misaligned-expand-2.c: New test.

From-SVN: r185336

gcc/ChangeLog

@@ -1,3 +1,8 @@
+2012-03-13  Martin Jambor  <mjambor@suse.cz>
+
+	* expr.c (expand_assignment): Handle misaligned scalar writes to
+	memory through top-level MEM_REFs by calling store_bit_field.
+
 2012-03-13  Richard Guenther  <rguenther@suse.de>
 
 	PR middle-end/52134

gcc/expr.c

@@ -4593,10 +4593,12 @@ expand_assignment (tree to, tree from, bool nontemporal)
   if ((TREE_CODE (to) == MEM_REF
        || TREE_CODE (to) == TARGET_MEM_REF)
       && mode != BLKmode
+      && !mem_ref_refers_to_non_mem_p (to)
       && ((align = get_object_or_type_alignment (to))
 	  < GET_MODE_ALIGNMENT (mode))
-      && ((icode = optab_handler (movmisalign_optab, mode))
+      && (((icode = optab_handler (movmisalign_optab, mode))
-	  != CODE_FOR_nothing))
+	   != CODE_FOR_nothing)
+	  || SLOW_UNALIGNED_ACCESS (mode, align)))
     {
       addr_space_t as
 	= TYPE_ADDR_SPACE (TREE_TYPE (TREE_TYPE (TREE_OPERAND (to, 0))));
@@ -4639,11 +4641,17 @@ expand_assignment (tree to, tree from, bool nontemporal)
       if (TREE_THIS_VOLATILE (to))
 	MEM_VOLATILE_P (mem) = 1;
 
-      create_fixed_operand (&ops[0], mem);
+      if (icode != CODE_FOR_nothing)
-      create_input_operand (&ops[1], reg, mode);
+	{
-      /* The movmisalign<mode> pattern cannot fail, else the assignment would
+	  create_fixed_operand (&ops[0], mem);
-	 silently be omitted.  */
+	  create_input_operand (&ops[1], reg, mode);
-      expand_insn (icode, 2, ops);
+	  /* The movmisalign<mode> pattern cannot fail, else the assignment
+	     would silently be omitted.  */
+	  expand_insn (icode, 2, ops);
+	}
+      else
+	store_bit_field (mem, GET_MODE_BITSIZE (mode),
+			 0, 0, 0, mode, reg);
       return;
     }
 

gcc/testsuite/ChangeLog

@@ -1,3 +1,7 @@
+2012-03-13  Martin Jambor  <mjambor@suse.cz>
+
+	* gcc.dg/misaligned-expand-2.c: New test.
+
 2012-03-13  Richard Guenther  <rguenther@suse.de>
 
 	PR middle-end/52134

gcc/testsuite/gcc.dg/misaligned-expand-2.c

@@ -0,0 +1,42 @@
+/* Test that expand can generate correct stores to misaligned data even on
+   strict alignment platforms.  */
+
+/* { dg-do run } */
+/* { dg-options "-O0" } */
+
+extern void abort ();
+
+typedef unsigned int myint __attribute__((aligned(1)));
+
+void
+foo (myint *p, unsigned int i)
+{
+  *p = i;
+}
+
+#define cst 0xdeadbeef
+#define NUM 8
+
+struct blah
+{
+  char c;
+  myint i[NUM];
+};
+
+struct blah g;
+
+#define cst 0xdeadbeef
+
+int
+main (int argc, char **argv)
+{
+  int k;
+
+  for (k = 0; k < NUM; k++)
+    {
+      foo (&g.i[k], cst);
+      if (g.i[k] != cst)
+	abort ();
+    }
+  return 0;
+}