x

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@14542 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/gcc/stor-layout.c b/gcc/stor-layout.c
index 83bfb99..7c4b4f6 100644 (file)
--- a/gcc/stor-layout.c
+++ b/gcc/stor-layout.c
@@ -835,6 +835,8 @@ layout_type (type)
       if (TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST)
        {
          tree field;
+         enum machine_mode mode = VOIDmode;
+
          /* A record which has any BLKmode members must itself be BLKmode;
             it can't go in a register.
             Unless the member is BLKmode only because it isn't aligned.  */
@@ -860,13 +862,23 @@ layout_type (type)
                  != ((TREE_INT_CST_LOW (DECL_SIZE (field)) + bitpos - 1)
                      / BITS_PER_WORD)
                  /* But there is no problem if the field is entire words.  */
-                 && TREE_INT_CST_LOW (DECL_SIZE (field)) % BITS_PER_WORD == 0)
+                 && TREE_INT_CST_LOW (DECL_SIZE (field)) % BITS_PER_WORD != 0)
                goto record_lose;
+
+             /* 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.  */
+             if (simple_cst_equal (TYPE_SIZE (type), DECL_SIZE (field)))
+               mode = DECL_MODE (field);
            }
 
-         TYPE_MODE (type)
-           = mode_for_size (TREE_INT_CST_LOW (TYPE_SIZE (type)),
-                            MODE_INT, 1);
+         if (mode != VOIDmode)
+           /* We only have one real field; use its mode.  */
+           TYPE_MODE (type) = mode;
+         else
+           TYPE_MODE (type)
+             = mode_for_size (TREE_INT_CST_LOW (TYPE_SIZE (type)),
+                              MODE_INT, 1);
 
          /* If structure's known alignment is less than
             what the scalar mode would need, and it matters,