* expr.c (expand_expr_unaligned): Add more code from full case

	that is needed when OP0 is in a register.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@30712 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index afd4fc9..beae01e 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+Mon Nov 29 16:56:42 1999  Richard Kenner  <kenner@vlsi1.ultra.nyu.edu>
+
+       * expr.c (expand_expr_unaligned): Add more code from full case
+       that is needed when OP0 is in a register.
+
 Mon Nov 29 18:09:39 1999  J"orn Rennecke <amylaar@cygnus.co.uk>
 
        * dwarfout.c (field_byte_offset): Size can be zero if there was

diff --git a/gcc/expr.c b/gcc/expr.c
index 4f9f439..bc6c93f 100644 (file)
--- a/gcc/expr.c
+++ b/gcc/expr.c
@@ -8643,10 +8643,66 @@ expand_expr_unaligned (exp, palign)
                                 TYPE_MODE (integer_type_node));
          }
 
-       /* Get a reference to just this component.  */
-       op0 = change_address (op0, mode1,
-                             plus_constant (XEXP (op0, 0),
-                                            (bitpos / BITS_PER_UNIT)));
+       /* In cases where an aligned union has an unaligned object
+          as a field, we might be extracting a BLKmode value from
+          an integer-mode (e.g., SImode) object.  Handle this case
+          by doing the extract into an object as wide as the field
+          (which we know to be the width of a basic mode), then
+          storing into memory, and changing the mode to BLKmode.
+          If we ultimately want the address (EXPAND_CONST_ADDRESS or
+          EXPAND_INITIALIZER), then we must not copy to a temporary.  */
+       if (mode1 == VOIDmode
+           || GET_CODE (op0) == REG || GET_CODE (op0) == SUBREG
+           || (SLOW_UNALIGNED_ACCESS
+               && (TYPE_ALIGN (type) > alignment * BITS_PER_UNIT
+                   || bitpos % TYPE_ALIGN (type) != 0)))
+         {
+           enum machine_mode ext_mode = mode_for_size (bitsize, MODE_INT, 1);
+
+           if (ext_mode == BLKmode)
+             {
+               /* In this case, BITPOS must start at a byte boundary.  */
+               if (GET_CODE (op0) != MEM
+                   || bitpos % BITS_PER_UNIT != 0)
+                 abort ();
+
+               op0 = change_address (op0, VOIDmode,
+                                     plus_constant (XEXP (op0, 0),
+                                                    bitpos / BITS_PER_UNIT));
+             }
+           else
+             {
+               rtx new = assign_stack_temp (ext_mode,
+                                            bitsize / BITS_PER_UNIT, 0);
+
+               op0 = extract_bit_field (validize_mem (op0), bitsize, bitpos,
+                                        unsignedp, NULL_RTX, ext_mode,
+                                        ext_mode, alignment,
+                                        int_size_in_bytes (TREE_TYPE (tem)));
+
+               /* If the result is a record type and BITSIZE is narrower than
+                  the mode of OP0, an integral mode, and this is a big endian
+                  machine, we must put the field into the high-order bits.  */
+               if (TREE_CODE (type) == RECORD_TYPE && BYTES_BIG_ENDIAN
+                   && GET_MODE_CLASS (GET_MODE (op0)) == MODE_INT
+                   && bitsize < GET_MODE_BITSIZE (GET_MODE (op0)))
+                 op0 = expand_shift (LSHIFT_EXPR, GET_MODE (op0), op0,
+                                     size_int (GET_MODE_BITSIZE
+                                               (GET_MODE (op0))
+                                               - bitsize),
+                                     op0, 1);
+
+
+               emit_move_insn (new, op0);
+               op0 = copy_rtx (new);
+               PUT_MODE (op0, BLKmode);
+             }
+         }
+       else
+         /* Get a reference to just this component.  */
+         op0 = change_address (op0, mode1,
+                                 plus_constant (XEXP (op0, 0),
+                                                (bitpos / BITS_PER_UNIT)));
 
        MEM_ALIAS_SET (op0) = get_alias_set (exp);