[backport from gcc-4.7/trunk r184214 <mikpe@it.uu.se>]

gcc/

2012-02-14  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/52244
	PR tree-optimization/51528
	* tree-sra.c (analyze_access_subtree): Only create INTEGER_TYPE
	replacements for integral types.

gcc/testsuite/

2012-02-14  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/52244
	PR tree-optimization/51528
	* gcc.dg/torture/pr52244.c: New testcase.

--- gcc-4.6.2/gcc/testsuite/gcc.dg/torture/pr52244.c.~1~	1970-01-01 01:00:00.000000000 +0100
+++ gcc-4.6.2/gcc/testsuite/gcc.dg/torture/pr52244.c	2012-02-18 20:06:34.000000000 +0100
@@ -0,0 +1,36 @@
+/* { dg-do run } */
+
+extern void abort (void);
+
+typedef union u_r 
+{
+  _Bool b;
+  unsigned char c;
+} u_t;
+
+u_t
+bar (void)
+{
+  u_t u;
+  u.c = 0x12;
+  return u;
+}
+
+u_t  __attribute__ ((noinline))
+foo (void)
+{
+  u_t u;
+
+  u.b = 1;
+  u = bar ();
+
+  return u;
+}
+
+int main (int argc, char **argv)
+{
+  u_t u = foo ();
+  if (u.c != 0x12)
+    abort ();
+  return 0;
+}
--- gcc-4.6.2/gcc/tree-sra.c.~1~	2012-02-18 20:01:47.000000000 +0100
+++ gcc-4.6.2/gcc/tree-sra.c	2012-02-18 20:06:34.000000000 +0100
@@ -1993,11 +1993,21 @@ analyze_access_subtree (struct access *r
 	      && (root->grp_scalar_write || root->grp_assignment_write))))
     {
       bool new_integer_type;
-      if (TREE_CODE (root->type) == ENUMERAL_TYPE)
+      /* Always create access replacements that cover the whole access.
+         For integral types this means the precision has to match.
+	 Avoid assumptions based on the integral type kind, too.  */
+      if (INTEGRAL_TYPE_P (root->type)
+	  && (TREE_CODE (root->type) != INTEGER_TYPE
+	      || TYPE_PRECISION (root->type) != root->size)
+	  /* But leave bitfield accesses alone.  */
+	  && (root->offset % BITS_PER_UNIT) == 0)
 	{
 	  tree rt = root->type;
-	  root->type = build_nonstandard_integer_type (TYPE_PRECISION (rt),
+	  root->type = build_nonstandard_integer_type (root->size,
 						       TYPE_UNSIGNED (rt));
+	  root->expr = build_ref_for_offset (UNKNOWN_LOCATION,
+					     root->base, root->offset,
+					     root->type, NULL, false);
 	  new_integer_type = true;
 	}
       else