Fixes for C++ structure layout breakage.

	* expmed.c (store_bit_field): Move integer pun code down after
	code that calls emit_move_insn for entire register move.
	* stor-layout.c (compute_record_mode): Revert Mar 25, Aug 18, and
	Oct 20 changes.  Only store mode in TYPE_MODE if RECORD_TYPE.

From-SVN: r37041

3 files changed, 29 insertions, 23 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index e4c278b..6e87a78 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2000-10-24  Jim Wilson  <wilson@cygnus.com>
+
+	* expmed.c (store_bit_field): Move integer pun code down after
+	code that calls emit_move_insn for entire register move.
+	* stor-layout.c (compute_record_mode): Revert Mar 25, Aug 18, and
+	Oct 20 changes.  Only store mode in TYPE_MODE if RECORD_TYPE.
+	
 2000-10-24  Richard Henderson  <rth@cygnus.com>
 
 	* rtlanal.c (rtx_unstable_p, rtx_varies_p): Don't consider pic
diff --git a/gcc/expmed.c b/gcc/expmed.c
index 2605062..254d052 100644
--- a/gcc/expmed.c
+++ b/gcc/expmed.c
@@ -269,21 +269,6 @@ store_bit_field (str_rtx, bitsize, bitnum, fieldmode, value, align, total_size)
       op0 = SUBREG_REG (op0);
     }
 
-  /* Make sure we are playing with integral modes.  Pun with subregs
-     if we aren't.  */
-  {
-    enum machine_mode imode = int_mode_for_mode (GET_MODE (op0));
-    if (imode != GET_MODE (op0))
-      {
-	if (GET_CODE (op0) == MEM)
-	  op0 = change_address (op0, imode, NULL_RTX);
-	else if (imode != BLKmode)
-	  op0 = gen_lowpart (imode, op0);
-	else
-	  abort ();
-      }
-  }
-
   /* If OP0 is a register, BITPOS must count within a word.
      But as we have it, it counts within whatever size OP0 now has.
      On a bigendian machine, these are not the same, so convert.  */
@@ -337,6 +322,23 @@ store_bit_field (str_rtx, bitsize, bitnum, fieldmode, value, align, total_size)
       return value;
     }
 
+  /* Make sure we are playing with integral modes.  Pun with subregs
+     if we aren't.  This must come after the entire register case above,
+     since that case is valid for any mode.  The following cases are only
+     valid for integral modes.  */
+  {
+    enum machine_mode imode = int_mode_for_mode (GET_MODE (op0));
+    if (imode != GET_MODE (op0))
+      {
+	if (GET_CODE (op0) == MEM)
+	  op0 = change_address (op0, imode, NULL_RTX);
+	else if (imode != BLKmode)
+	  op0 = gen_lowpart (imode, op0);
+	else
+	  abort ();
+      }
+  }
+
   /* Storing an lsb-aligned field in a register
      can be done with a movestrict instruction.  */
 
diff --git a/gcc/stor-layout.c b/gcc/stor-layout.c
index ea9ee01..797b4ce 100644
--- a/gcc/stor-layout.c
+++ b/gcc/stor-layout.c
@@ -1065,12 +1065,8 @@ compute_record_mode (type)
 
       /* If this field is the whole struct, remember its mode so
 	 that, say, we can put a double in a class into a DF
-	 register instead of forcing it to live in the stack.  However,
-	 we don't support using such a mode if there is no integer mode
-	 of the same size, so don't set it here.  */
-      if (field == TYPE_FIELDS (type) && TREE_CHAIN (field) == 0
-	  && int_mode_for_mode (DECL_MODE (field)) != BLKmode
-	  && operand_equal_p (DECL_SIZE (field), TYPE_SIZE (type), 1))
+	 register instead of forcing it to live in the stack.  */
+      if (simple_cst_equal (TYPE_SIZE (type), DECL_SIZE (field)))
 	mode = DECL_MODE (field);
 
 #ifdef STRUCT_FORCE_BLK
@@ -1081,8 +1077,9 @@ compute_record_mode (type)
 #endif /* STRUCT_FORCE_BLK  */
     }
 
-  if (mode != VOIDmode)
-    /* We only have one real field; use its mode.  */
+  /* If we only have one real field; use its mode.  This only applies to
+     RECORD_TYPE.  This does not apply to unions.  */
+  if (TREE_CODE (type) == RECORD_TYPE && mode != VOIDmode)
     TYPE_MODE (type) = mode;
   else
     TYPE_MODE (type) = mode_for_size_tree (TYPE_SIZE (type), MODE_INT, 1);