/* Generate code for computing expression EXP,
and storing the value into TARGET.
- If WANT_VALUE & 1 is nonzero, return a copy of the value
- not in TARGET, so that we can be sure to use the proper
- value in a containing expression even if TARGET has something
- else stored in it. If possible, we copy the value through a pseudo
- and return that pseudo. Or, if the value is constant, we try to
- return the constant. In some cases, we return a pseudo
- copied *from* TARGET.
-
If the mode is BLKmode then we may return TARGET itself.
It turns out that in BLKmode it doesn't cause a problem.
because C has no operators that could combine two different
with no sequence point. Will other languages need this to
be more thorough?
- If WANT_VALUE & 1 is 0, we return NULL, to make sure
- to catch quickly any cases where the caller uses the value
- and fails to set WANT_VALUE.
-
If WANT_VALUE & 2 is set, this is a store into a call param on the
stack, and block moves may need to be treated specially. */
int dont_return_target = 0;
int dont_store_target = 0;
+ /* The bit 0 of WANT_VALUE used to be used to request a value of the
+ expression. This feature has been removed. */
+ gcc_assert ((want_value & 1) == 0);
+
if (VOID_TYPE_P (TREE_TYPE (exp)))
{
/* C++ can generate ?: expressions with a throw expression in one
emit_label (lab2);
OK_DEFER_POP;
- return want_value & 1 ? target : NULL_RTX;
- }
- else if ((want_value & 1) != 0
- && MEM_P (target)
- && ! MEM_VOLATILE_P (target)
- && GET_MODE (target) != BLKmode)
- /* If target is in memory and caller wants value in a register instead,
- arrange that. Pass TARGET as target for expand_expr so that,
- if EXP is another assignment, WANT_VALUE will be nonzero for it.
- We know expand_expr will not use the target in that case.
- Don't do this if TARGET is volatile because we are supposed
- to write it and then read it. */
- {
- temp = expand_expr (exp, target, GET_MODE (target),
- want_value & 2 ? EXPAND_STACK_PARM : EXPAND_NORMAL);
- if (GET_MODE (temp) != BLKmode && GET_MODE (temp) != VOIDmode)
- {
- /* If TEMP is already in the desired TARGET, only copy it from
- memory and don't store it there again. */
- if (temp == target
- || (rtx_equal_p (temp, target)
- && ! side_effects_p (temp) && ! side_effects_p (target)))
- dont_store_target = 1;
- temp = copy_to_reg (temp);
- }
- dont_return_target = 1;
+ return NULL_RTX;
}
else if (GET_CODE (target) == SUBREG && SUBREG_PROMOTED_VAR_P (target))
/* If this is a scalar in a register that is stored in a wider mode
{
rtx inner_target = 0;
- /* If we don't want a value, we can do the conversion inside EXP,
- which will often result in some optimizations. Do the conversion
- in two steps: first change the signedness, if needed, then
- the extend. But don't do this if the type of EXP is a subtype
- of something else since then the conversion might involve
- more than just converting modes. */
- if ((want_value & 1) == 0
- && INTEGRAL_TYPE_P (TREE_TYPE (exp))
+ /* We can do the conversion inside EXP, which will often result
+ in some optimizations. Do the conversion in two steps: first
+ change the signedness, if needed, then the extend. But don't
+ do this if the type of EXP is a subtype of something else
+ since then the conversion might involve more than just
+ converting modes. */
+ if (INTEGRAL_TYPE_P (TREE_TYPE (exp))
&& TREE_TYPE (TREE_TYPE (exp)) == 0
&& (!lang_hooks.reduce_bit_field_operations
|| (GET_MODE_PRECISION (GET_MODE (target))
temp = expand_expr (exp, inner_target, VOIDmode,
want_value & 2 ? EXPAND_STACK_PARM : EXPAND_NORMAL);
- /* If TEMP is a MEM and we want a result value, make the access
- now so it gets done only once. Strictly speaking, this is
- only necessary if the MEM is volatile, or if the address
- overlaps TARGET. But not performing the load twice also
- reduces the amount of rtl we generate and then have to CSE. */
- if (MEM_P (temp) && (want_value & 1) != 0)
- temp = copy_to_reg (temp);
-
/* If TEMP is a VOIDmode constant, use convert_modes to make
sure that we properly convert it. */
if (CONSTANT_P (temp) && GET_MODE (temp) == VOIDmode)
convert_move (SUBREG_REG (target), temp,
SUBREG_PROMOTED_UNSIGNED_P (target));
- /* If we promoted a constant, change the mode back down to match
- target. Otherwise, the caller might get confused by a result whose
- mode is larger than expected. */
-
- if ((want_value & 1) != 0 && GET_MODE (temp) != GET_MODE (target))
- {
- if (GET_MODE (temp) != VOIDmode)
- {
- temp = gen_lowpart_SUBREG (GET_MODE (target), temp);
- SUBREG_PROMOTED_VAR_P (temp) = 1;
- SUBREG_PROMOTED_UNSIGNED_SET (temp,
- SUBREG_PROMOTED_UNSIGNED_P (target));
- }
- else
- temp = convert_modes (GET_MODE (target),
- GET_MODE (SUBREG_REG (target)),
- temp, SUBREG_PROMOTED_UNSIGNED_P (target));
- }
-
- return want_value & 1 ? temp : NULL_RTX;
+ return NULL_RTX;
}
else
{
&& REGNO (target) < FIRST_PSEUDO_REGISTER)
&& !(MEM_P (target) && MEM_VOLATILE_P (target))
&& ! rtx_equal_p (temp, target)
- && (CONSTANT_P (temp) || (want_value & 1) != 0))
+ && CONSTANT_P (temp))
dont_return_target = 1;
}
}
}
- /* If we don't want a value, return NULL_RTX. */
- if ((want_value & 1) == 0)
- return NULL_RTX;
-
- /* If we are supposed to return TEMP, do so as long as it isn't a MEM.
- ??? The latter test doesn't seem to make sense. */
- else if (dont_return_target && !MEM_P (temp))
- return temp;
-
- /* Return TARGET itself if it is a hard register. */
- else if ((want_value & 1) != 0
- && GET_MODE (target) != BLKmode
- && ! (REG_P (target)
- && REGNO (target) < FIRST_PSEUDO_REGISTER))
- return copy_to_reg (target);
-
- else
- return target;
+ return NULL_RTX;
}
\f
/* Examine CTOR. Discover how many scalar fields are set to nonzero
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