/* Convert tree expression to rtl instructions, for GNU compiler.
Copyright (C) 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
- 2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
+ 2000, 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
This file is part of GCC.
true, NULL_RTX, imode, imode);
}
\f
-/* A subroutine of emit_move_via_alt_mode. Yet another lowpart generator.
+/* A subroutine of emit_move_insn_1. Yet another lowpart generator.
NEW_MODE and OLD_MODE are the same size. Return NULL if X cannot be
- represented in NEW_MODE. */
+ represented in NEW_MODE. If FORCE is true, this will never happen, as
+ we'll force-create a SUBREG if needed. */
static rtx
emit_move_change_mode (enum machine_mode new_mode,
- enum machine_mode old_mode, rtx x)
+ enum machine_mode old_mode, rtx x, bool force)
{
rtx ret;
}
else
{
- /* Note that we do want simplify_subreg's behaviour of validating
+ /* Note that we do want simplify_subreg's behavior of validating
that the new mode is ok for a hard register. If we were to use
simplify_gen_subreg, we would create the subreg, but would
probably run into the target not being able to implement it. */
- ret = simplify_subreg (new_mode, x, old_mode, 0);
+ /* Except, of course, when FORCE is true, when this is exactly what
+ we want. Which is needed for CCmodes on some targets. */
+ if (force)
+ ret = simplify_gen_subreg (new_mode, x, old_mode, 0);
+ else
+ ret = simplify_subreg (new_mode, x, old_mode, 0);
}
return ret;
}
/* A subroutine of emit_move_insn_1. Generate a move from Y into X using
- ALT_MODE instead of the operand's natural mode, MODE. CODE is the insn
- code for the move in ALT_MODE, and is known to be valid. Returns the
- instruction emitted, or NULL if X or Y cannot be represented in ALT_MODE. */
-
-static rtx
-emit_move_via_alt_mode (enum machine_mode alt_mode, enum machine_mode mode,
- enum insn_code code, rtx x, rtx y)
-{
- x = emit_move_change_mode (alt_mode, mode, x);
- if (x == NULL_RTX)
- return NULL_RTX;
- y = emit_move_change_mode (alt_mode, mode, y);
- if (y == NULL_RTX)
- return NULL_RTX;
- return emit_insn (GEN_FCN (code) (x, y));
-}
-
-/* A subroutine of emit_move_insn_1. Generate a move from Y into X using
an integer mode of the same size as MODE. Returns the instruction
emitted, or NULL if such a move could not be generated. */
if (code == CODE_FOR_nothing)
return NULL_RTX;
- return emit_move_via_alt_mode (imode, mode, code, x, y);
+ x = emit_move_change_mode (imode, mode, x, false);
+ if (x == NULL_RTX)
+ return NULL_RTX;
+ y = emit_move_change_mode (imode, mode, y, false);
+ if (y == NULL_RTX)
+ return NULL_RTX;
+ return emit_insn (GEN_FCN (code) (x, y));
}
/* A subroutine of emit_move_insn_1. X is a push_operand in MODE.
if (push_operand (x, mode))
return emit_move_complex_push (mode, x, y);
- /* For memory to memory moves, optimial behaviour can be had with the
+ /* For memory to memory moves, optimal behavior can be had with the
existing block move logic. */
if (MEM_P (x) && MEM_P (y))
{
{
enum insn_code code = mov_optab->handlers[CCmode].insn_code;
if (code != CODE_FOR_nothing)
- return emit_move_via_alt_mode (CCmode, mode, code, x, y);
+ {
+ x = emit_move_change_mode (CCmode, mode, x, true);
+ y = emit_move_change_mode (CCmode, mode, y, true);
+ return emit_insn (GEN_FCN (code) (x, y));
+ }
}
/* Otherwise, find the MODE_INT mode of the same width. */
* how many scalar fields are set to non-constant values,
and place it in *P_NC_ELTS; and
* how many scalar fields in total are in CTOR,
- and place it in *P_ELT_COUNT. */
+ and place it in *P_ELT_COUNT.
+ * if a type is a union, and the initializer from the constructor
+ is not the largest element in the union, then set *p_must_clear. */
static void
categorize_ctor_elements_1 (tree ctor, HOST_WIDE_INT *p_nz_elts,
HOST_WIDE_INT *p_nc_elts,
- HOST_WIDE_INT *p_elt_count)
+ HOST_WIDE_INT *p_elt_count,
+ bool *p_must_clear)
{
HOST_WIDE_INT nz_elts, nc_elts, elt_count;
tree list;
{
case CONSTRUCTOR:
{
- HOST_WIDE_INT nz = 0, nc = 0, count = 0;
- categorize_ctor_elements_1 (value, &nz, &nc, &count);
+ HOST_WIDE_INT nz = 0, nc = 0, ic = 0;
+ categorize_ctor_elements_1 (value, &nz, &nc, &ic, p_must_clear);
nz_elts += mult * nz;
nc_elts += mult * nc;
- elt_count += mult * count;
+ elt_count += mult * ic;
}
break;
}
}
+ if (!*p_must_clear
+ && (TREE_CODE (TREE_TYPE (ctor)) == UNION_TYPE
+ || TREE_CODE (TREE_TYPE (ctor)) == QUAL_UNION_TYPE))
+ {
+ tree init_sub_type;
+ bool clear_this = true;
+
+ list = CONSTRUCTOR_ELTS (ctor);
+ if (list)
+ {
+ /* We don't expect more than one element of the union to be
+ initialized. Not sure what we should do otherwise... */
+ gcc_assert (TREE_CHAIN (list) == NULL);
+
+ init_sub_type = TREE_TYPE (TREE_VALUE (list));
+
+ /* ??? We could look at each element of the union, and find the
+ largest element. Which would avoid comparing the size of the
+ initialized element against any tail padding in the union.
+ Doesn't seem worth the effort... */
+ if (simple_cst_equal (TYPE_SIZE (TREE_TYPE (ctor)),
+ TYPE_SIZE (init_sub_type)) == 1)
+ {
+ /* And now we have to find out if the element itself is fully
+ constructed. E.g. for union { struct { int a, b; } s; } u
+ = { .s = { .a = 1 } }. */
+ if (elt_count == count_type_elements (init_sub_type))
+ clear_this = false;
+ }
+ }
+
+ *p_must_clear = clear_this;
+ }
+
*p_nz_elts += nz_elts;
*p_nc_elts += nc_elts;
*p_elt_count += elt_count;
void
categorize_ctor_elements (tree ctor, HOST_WIDE_INT *p_nz_elts,
HOST_WIDE_INT *p_nc_elts,
- HOST_WIDE_INT *p_elt_count)
+ HOST_WIDE_INT *p_elt_count,
+ bool *p_must_clear)
{
*p_nz_elts = 0;
*p_nc_elts = 0;
*p_elt_count = 0;
- categorize_ctor_elements_1 (ctor, p_nz_elts, p_nc_elts, p_elt_count);
+ *p_must_clear = false;
+ categorize_ctor_elements_1 (ctor, p_nz_elts, p_nc_elts, p_elt_count,
+ p_must_clear);
}
/* Count the number of scalars in TYPE. Return -1 on overflow or
{
HOST_WIDE_INT nz_elts, nc_elts, count, elts;
+ bool must_clear;
+
+ categorize_ctor_elements (exp, &nz_elts, &nc_elts, &count, &must_clear);
+ if (must_clear)
+ return 1;
- categorize_ctor_elements (exp, &nz_elts, &nc_elts, &count);
elts = count_type_elements (TREE_TYPE (exp));
return nz_elts < elts / 4;
enum machine_mode eltmode = TYPE_MODE (elttype);
HOST_WIDE_INT bitsize;
HOST_WIDE_INT bitpos;
- rtx *vector = NULL;
+ rtvec vector = NULL;
unsigned n_elts;
gcc_assert (eltmode != BLKmode);
{
unsigned int i;
- vector = alloca (n_elts);
+ vector = rtvec_alloc (n_elts);
for (i = 0; i < n_elts; i++)
- vector [i] = CONST0_RTX (GET_MODE_INNER (mode));
+ RTVEC_ELT (vector, i) = CONST0_RTX (GET_MODE_INNER (mode));
}
}
/* Vector CONSTRUCTORs should only be built from smaller
vectors in the case of BLKmode vectors. */
gcc_assert (TREE_CODE (TREE_TYPE (value)) != VECTOR_TYPE);
- vector[eltpos] = expand_expr (value, NULL_RTX, VOIDmode, 0);
+ RTVEC_ELT (vector, eltpos)
+ = expand_expr (value, NULL_RTX, VOIDmode, 0);
}
else
{
if (vector)
emit_insn (GEN_FCN (icode)
(target,
- gen_rtx_PARALLEL (GET_MODE (target),
- gen_rtvec_v (n_elts, vector))));
+ gen_rtx_PARALLEL (GET_MODE (target), vector)));
break;
}
&& TREE_CODE (TYPE_SIZE (TREE_TYPE (exp))) == INTEGER_CST
&& compare_tree_int (TYPE_SIZE (TREE_TYPE (exp)), bitsize) != 0))
{
- rtx temp = expand_expr (exp, NULL_RTX, VOIDmode, 0);
+ rtx temp;
+
+ /* If EXP is a NOP_EXPR of precision less than its mode, then that
+ implies a mask operation. If the precision is the same size as
+ the field we're storing into, that mask is redundant. This is
+ particularly common with bit field assignments generated by the
+ C front end. */
+ if (TREE_CODE (exp) == NOP_EXPR)
+ {
+ tree type = TREE_TYPE (exp);
+ if (INTEGRAL_TYPE_P (type)
+ && TYPE_PRECISION (type) < GET_MODE_BITSIZE (TYPE_MODE (type))
+ && bitsize == TYPE_PRECISION (type))
+ {
+ type = TREE_TYPE (TREE_OPERAND (exp, 0));
+ if (INTEGRAL_TYPE_P (type) && TYPE_PRECISION (type) >= bitsize)
+ exp = TREE_OPERAND (exp, 0);
+ }
+ }
+
+ temp = expand_expr (exp, NULL_RTX, VOIDmode, 0);
/* If BITSIZE is narrower than the size of the type of EXP
we will be narrowing TEMP. Normally, what's wanted are the
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