re PR libfortran/39665 (Fortran IO using unaligned accesses to read/write doubles.)

2009-04-09  Janne Blomqvist  <jb@gcc.gnu.org>

	PR fortran/39665
	* io/io.h (st_parameter_dt): Add aligned attribute to u.p.value.
	* io/read.c (convert_real): Add note about alignment requirements.

From-SVN: r145852

libgfortran/ChangeLog

+2009-04-09  Janne Blomqvist  <jb@gcc.gnu.org>
+
+	PR libfortran/39665
+	* io/io.h (st_parameter_dt): Add aligned attribute to u.p.value.
+	* io/read.c (convert_real): Add note about alignment requirements.
+
 2009-04-09  Nick Clifton  <nickc@redhat.com>
 
 	* m4/cshift0.m4: Change copyright header to refer to version 3

libgfortran/io/io.h

@@ -498,10 +498,11 @@ typedef struct st_parameter_dt
 	  /* A flag used to identify when a non-standard expanded namelist read
 	     has occurred.  */
 	  int expanded_read;
-	  /* Storage area for values except for strings.  Must be large
-	     enough to hold a complex value (two reals) of the largest
-	     kind.  */
-	  char value[32];
+	  /* Storage area for values except for strings.  Must be
+	     large enough to hold a complex value (two reals) of the
+	     largest kind.  It must also be sufficiently aligned for
+	     assigning any type we use into it.  */
+	  char value[32]  __attribute__ ((aligned (__BIGGEST_ALIGNMENT__)));
 	  GFC_IO_INT size_used;
 	} p;
       /* This pad size must be equal to the pad_size declared in

libgfortran/io/read.c

@@ -126,8 +126,10 @@ max_value (int length, int signed_flag)
 
 /* convert_real()-- Convert a character representation of a floating
  * point number to the machine number.  Returns nonzero if there is a
- * range problem during conversion.  TODO: handle not-a-numbers and
- * infinities.  */
+ * range problem during conversion.  Note: many architectures
+ * (e.g. IA-64, HP-PA) require that the storage pointed to by the dest
+ * argument is properly aligned for the type in question.  TODO:
+ * handle not-a-numbers and infinities.  */
 
 int
 convert_real (st_parameter_dt *dtp, void *dest, const char *buffer, int length)