return ret;
}
+/* Return true if word I of OP lies entirely in the
+ undefined bits of a paradoxical subreg. */
+
+static bool
+undefined_operand_subword_p (rtx op, int i)
+{
+ enum machine_mode innermode, innermostmode;
+ int offset;
+ if (GET_CODE (op) != SUBREG)
+ return false;
+ innermode = GET_MODE (op);
+ innermostmode = GET_MODE (SUBREG_REG (op));
+ offset = i * UNITS_PER_WORD + SUBREG_BYTE (op);
+ /* The SUBREG_BYTE represents offset, as if the value were stored in
+ memory, except for a paradoxical subreg where we define
+ SUBREG_BYTE to be 0; undo this exception as in
+ simplify_subreg. */
+ if (SUBREG_BYTE (op) == 0
+ && GET_MODE_SIZE (innermostmode) < GET_MODE_SIZE (innermode))
+ {
+ int difference = (GET_MODE_SIZE (innermostmode) - GET_MODE_SIZE (innermode));
+ if (WORDS_BIG_ENDIAN)
+ offset += (difference / UNITS_PER_WORD) * UNITS_PER_WORD;
+ if (BYTES_BIG_ENDIAN)
+ offset += difference % UNITS_PER_WORD;
+ }
+ if (offset >= GET_MODE_SIZE (innermostmode)
+ || offset <= -GET_MODE_SIZE (word_mode))
+ return true;
+ return false;
+}
+
/* A subroutine of emit_move_insn_1. Generate a move from Y into X.
MODE is any multi-word or full-word mode that lacks a move_insn
pattern. Note that you will get better code if you define such
i++)
{
rtx xpart = operand_subword (x, i, 1, mode);
- rtx ypart = operand_subword (y, i, 1, mode);
+ rtx ypart;
+
+ /* Do not generate code for a move if it would come entirely
+ from the undefined bits of a paradoxical subreg. */
+ if (undefined_operand_subword_p (y, i))
+ continue;
+
+ ypart = operand_subword (y, i, 1, mode);
/* If we can't get a part of Y, put Y into memory if it is a
constant. Otherwise, force it into a register. Then we must
return safe_from_p (x, exp, 0);
}
}
+ else if (TREE_CODE (exp) == CONSTRUCTOR)
+ {
+ constructor_elt *ce;
+ unsigned HOST_WIDE_INT idx;
+
+ for (idx = 0;
+ VEC_iterate (constructor_elt, CONSTRUCTOR_ELTS (exp), idx, ce);
+ idx++)
+ if ((ce->index != NULL_TREE && !safe_from_p (x, ce->index, 0))
+ || !safe_from_p (x, ce->value, 0))
+ return 0;
+ return 1;
+ }
else if (TREE_CODE (exp) == ERROR_MARK)
return 1; /* An already-visited SAVE_EXPR? */
else