Commit 10055ae2 by Brendan Kehoe

Cygnus<-->FSF merge.

From-SVN: r3162
parent 76e616db
......@@ -369,7 +369,7 @@ OBJS = toplev.o version.o tree.o print-tree.o stor-layout.o fold-const.o \
regclass.o local-alloc.o global.o reload.o reload1.o caller-save.o \
insn-peep.o reorg.o sched.o final.o recog.o reg-stack.o \
insn-recog.o insn-extract.o insn-output.o insn-emit.o \
insn-attrtab.o aux-output.o getpwd.o $(EXTRA_OBJS)
insn-attrtab.o aux-output.o getpwd.o convert.o $(EXTRA_OBJS)
# GEN files are listed separately, so they can be built before doing parallel
# makes for cc1 or cc1plus. Otherwise sequent parallel make attempts to load
......
......@@ -26,6 +26,7 @@ the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
#include "config.h"
#include "tree.h"
#include "flags.h"
#include "convert.h"
/* Change of width--truncation and extension of integers or reals--
is represented with NOP_EXPR. Proper functioning of many things
......@@ -37,7 +38,7 @@ the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
Here is a list of all the functions that assume that widening and
narrowing is always done with a NOP_EXPR:
In c-convert.c, convert_to_integer.
In convert.c, convert_to_integer.
In c-typeck.c, build_binary_op (boolean ops), and truthvalue_conversion.
In expr.c: expand_expr, for operands of a MULT_EXPR.
In fold-const.c: fold.
......@@ -45,330 +46,7 @@ the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
/* Subroutines of `convert'. */
static tree
convert_to_pointer (type, expr)
tree type, expr;
{
register tree intype = TREE_TYPE (expr);
register enum tree_code form = TREE_CODE (intype);
if (integer_zerop (expr))
{
if (type == TREE_TYPE (null_pointer_node))
return null_pointer_node;
expr = build_int_2 (0, 0);
TREE_TYPE (expr) = type;
return expr;
}
if (form == POINTER_TYPE)
return build1 (NOP_EXPR, type, expr);
if (form == INTEGER_TYPE || form == ENUMERAL_TYPE)
{
if (type_precision (intype) == POINTER_SIZE)
return build1 (CONVERT_EXPR, type, expr);
expr = convert (type_for_size (POINTER_SIZE, 0), expr);
if (TYPE_MODE (TREE_TYPE (expr)) != TYPE_MODE (type))
/* There is supposed to be some integral type
that is the same width as a pointer. */
abort ();
return convert_to_pointer (type, expr);
}
error ("cannot convert to a pointer type");
return null_pointer_node;
}
static tree
convert_to_real (type, expr)
tree type, expr;
{
register enum tree_code form = TREE_CODE (TREE_TYPE (expr));
if (form == REAL_TYPE)
return build1 (flag_float_store ? CONVERT_EXPR : NOP_EXPR,
type, expr);
if (form == INTEGER_TYPE || form == ENUMERAL_TYPE)
return build1 (FLOAT_EXPR, type, expr);
if (form == POINTER_TYPE)
error ("pointer value used where a float was expected");
else
error ("aggregate value used where a float was expected");
{
register tree tem = make_node (REAL_CST);
TREE_TYPE (tem) = type;
TREE_REAL_CST (tem) = REAL_VALUE_ATOF ("0.0");
return tem;
}
}
/* The result of this is always supposed to be a newly created tree node
not in use in any existing structure. */
static tree
convert_to_integer (type, expr)
tree type, expr;
{
register tree intype = TREE_TYPE (expr);
register enum tree_code form = TREE_CODE (intype);
if (form == POINTER_TYPE)
{
if (integer_zerop (expr))
expr = integer_zero_node;
else
expr = fold (build1 (CONVERT_EXPR,
type_for_size (POINTER_SIZE, 0), expr));
intype = TREE_TYPE (expr);
form = TREE_CODE (intype);
if (intype == type)
return expr;
}
if (form == INTEGER_TYPE || form == ENUMERAL_TYPE)
{
register unsigned outprec = TYPE_PRECISION (type);
register unsigned inprec = TYPE_PRECISION (intype);
register enum tree_code ex_form = TREE_CODE (expr);
/* If we are widening the type, put in an explicit conversion.
Similarly if we are not changing the width. However, if this is
a logical operation that just returns 0 or 1, we can change the
type of the expression (see below). */
if (TREE_CODE_CLASS (ex_form) == '<'
|| ex_form == TRUTH_AND_EXPR || ex_form == TRUTH_ANDIF_EXPR
|| ex_form == TRUTH_OR_EXPR || ex_form == TRUTH_ORIF_EXPR
|| ex_form == TRUTH_XOR_EXPR || ex_form == TRUTH_NOT_EXPR)
{
TREE_TYPE (expr) = type;
return expr;
}
else if (outprec >= inprec)
return build1 (NOP_EXPR, type, expr);
/* Here detect when we can distribute the truncation down past some arithmetic.
For example, if adding two longs and converting to an int,
we can equally well convert both to ints and then add.
For the operations handled here, such truncation distribution
is always safe.
It is desirable in these cases:
1) when truncating down to full-word from a larger size
2) when truncating takes no work.
3) when at least one operand of the arithmetic has been extended
(as by C's default conversions). In this case we need two conversions
if we do the arithmetic as already requested, so we might as well
truncate both and then combine. Perhaps that way we need only one.
Note that in general we cannot do the arithmetic in a type
shorter than the desired result of conversion, even if the operands
are both extended from a shorter type, because they might overflow
if combined in that type. The exceptions to this--the times when
two narrow values can be combined in their narrow type even to
make a wider result--are handled by "shorten" in build_binary_op. */
switch (ex_form)
{
case RSHIFT_EXPR:
/* We can pass truncation down through right shifting
when the shift count is a nonpositive constant. */
if (TREE_CODE (TREE_OPERAND (expr, 1)) == INTEGER_CST
&& tree_int_cst_lt (TREE_OPERAND (expr, 1), integer_one_node))
goto trunc1;
break;
case LSHIFT_EXPR:
/* We can pass truncation down through left shifting
when the shift count is a nonnegative constant. */
if (TREE_CODE (TREE_OPERAND (expr, 1)) == INTEGER_CST
&& ! tree_int_cst_lt (TREE_OPERAND (expr, 1), integer_zero_node)
&& TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST)
{
/* If shift count is less than the width of the truncated type,
really shift. */
if (tree_int_cst_lt (TREE_OPERAND (expr, 1), TYPE_SIZE (type)))
/* In this case, shifting is like multiplication. */
goto trunc1;
else
/* If it is >= that width, result is zero.
Handling this with trunc1 would give the wrong result:
(int) ((long long) a << 32) is well defined (as 0)
but (int) a << 32 is undefined and would get a warning. */
return convert_to_integer (type, integer_zero_node);
}
break;
case MAX_EXPR:
case MIN_EXPR:
case MULT_EXPR:
{
tree arg0 = get_unwidened (TREE_OPERAND (expr, 0), type);
tree arg1 = get_unwidened (TREE_OPERAND (expr, 1), type);
/* Don't distribute unless the output precision is at least as big
as the actual inputs. Otherwise, the comparison of the
truncated values will be wrong. */
if (outprec >= TYPE_PRECISION (TREE_TYPE (arg0))
&& outprec >= TYPE_PRECISION (TREE_TYPE (arg1))
/* If signedness of arg0 and arg1 don't match,
we can't necessarily find a type to compare them in. */
&& (TREE_UNSIGNED (TREE_TYPE (arg0))
== TREE_UNSIGNED (TREE_TYPE (arg1))))
goto trunc1;
break;
}
case PLUS_EXPR:
case MINUS_EXPR:
case BIT_AND_EXPR:
case BIT_IOR_EXPR:
case BIT_XOR_EXPR:
case BIT_ANDTC_EXPR:
trunc1:
{
tree arg0 = get_unwidened (TREE_OPERAND (expr, 0), type);
tree arg1 = get_unwidened (TREE_OPERAND (expr, 1), type);
if (outprec >= BITS_PER_WORD
|| TRULY_NOOP_TRUNCATION (outprec, inprec)
|| inprec > TYPE_PRECISION (TREE_TYPE (arg0))
|| inprec > TYPE_PRECISION (TREE_TYPE (arg1)))
{
/* Do the arithmetic in type TYPEX,
then convert result to TYPE. */
register tree typex = type;
/* Can't do arithmetic in enumeral types
so use an integer type that will hold the values. */
if (TREE_CODE (typex) == ENUMERAL_TYPE)
typex = type_for_size (TYPE_PRECISION (typex),
TREE_UNSIGNED (typex));
/* But now perhaps TYPEX is as wide as INPREC.
In that case, do nothing special here.
(Otherwise would recurse infinitely in convert. */
if (TYPE_PRECISION (typex) != inprec)
{
/* Don't do unsigned arithmetic where signed was wanted,
or vice versa.
Exception: if either of the original operands were
unsigned then can safely do the work as unsigned.
And we may need to do it as unsigned
if we truncate to the original size. */
typex = ((TREE_UNSIGNED (TREE_TYPE (expr))
|| TREE_UNSIGNED (TREE_TYPE (arg0))
|| TREE_UNSIGNED (TREE_TYPE (arg1)))
? unsigned_type (typex) : signed_type (typex));
return convert (type,
build_binary_op (ex_form,
convert (typex, arg0),
convert (typex, arg1),
0));
}
}
}
break;
case NEGATE_EXPR:
case BIT_NOT_EXPR:
{
register tree typex = type;
/* Can't do arithmetic in enumeral types
so use an integer type that will hold the values. */
if (TREE_CODE (typex) == ENUMERAL_TYPE)
typex = type_for_size (TYPE_PRECISION (typex),
TREE_UNSIGNED (typex));
/* But now perhaps TYPEX is as wide as INPREC.
In that case, do nothing special here.
(Otherwise would recurse infinitely in convert. */
if (TYPE_PRECISION (typex) != inprec)
{
/* Don't do unsigned arithmetic where signed was wanted,
or vice versa. */
typex = (TREE_UNSIGNED (TREE_TYPE (expr))
? unsigned_type (typex) : signed_type (typex));
return convert (type,
build_unary_op (ex_form,
convert (typex, TREE_OPERAND (expr, 0)),
1));
}
}
case NOP_EXPR:
/* If truncating after truncating, might as well do all at once.
If truncating after extending, we may get rid of wasted work. */
return convert (type, get_unwidened (TREE_OPERAND (expr, 0), type));
case COND_EXPR:
/* Can treat the two alternative values like the operands
of an arithmetic expression. */
{
tree arg1 = get_unwidened (TREE_OPERAND (expr, 1), type);
tree arg2 = get_unwidened (TREE_OPERAND (expr, 2), type);
if (outprec >= BITS_PER_WORD
|| TRULY_NOOP_TRUNCATION (outprec, inprec)
|| inprec > TYPE_PRECISION (TREE_TYPE (arg1))
|| inprec > TYPE_PRECISION (TREE_TYPE (arg2)))
{
/* Do the arithmetic in type TYPEX,
then convert result to TYPE. */
register tree typex = type;
/* Can't do arithmetic in enumeral types
so use an integer type that will hold the values. */
if (TREE_CODE (typex) == ENUMERAL_TYPE)
typex = type_for_size (TYPE_PRECISION (typex),
TREE_UNSIGNED (typex));
/* But now perhaps TYPEX is as wide as INPREC.
In that case, do nothing special here.
(Otherwise would recurse infinitely in convert. */
if (TYPE_PRECISION (typex) != inprec)
{
/* Don't do unsigned arithmetic where signed was wanted,
or vice versa. */
typex = (TREE_UNSIGNED (TREE_TYPE (expr))
? unsigned_type (typex) : signed_type (typex));
return convert (type,
fold (build (COND_EXPR, typex,
TREE_OPERAND (expr, 0),
convert (typex, arg1),
convert (typex, arg2))));
}
else
/* It is sometimes worthwhile
to push the narrowing down through the conditional. */
return fold (build (COND_EXPR, type,
TREE_OPERAND (expr, 0),
convert (type, TREE_OPERAND (expr, 1)),
convert (type, TREE_OPERAND (expr, 2))));
}
}
}
return build1 (NOP_EXPR, type, expr);
}
if (form == REAL_TYPE)
return build1 (FIX_TRUNC_EXPR, type, expr);
error ("aggregate value used where an integer was expected");
{
register tree tem = build_int_2 (0, 0);
TREE_TYPE (tem) = type;
return tem;
}
}
/* Create an expression whose value is that of EXPR,
converted to type TYPE. The TREE_TYPE of the value
......
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