1 /* Utility routines for data type conversion for GNU C.
2 Copyright (C) 1987, 1988, 1991, 1992, 1993, 1994, 1995, 1997,
3 1998 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation; either version 2, or (at your option) any later
12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING. If not, write to the Free
19 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
23 /* These routines are somewhat language-independent utility function
24 intended to be called by the language-specific convert () functions. */
28 #include "coretypes.h"
34 #include "langhooks.h"
36 /* Convert EXPR to some pointer or reference type TYPE.
38 EXPR must be pointer, reference, integer, enumeral, or literal zero;
39 in other cases error is called. */
42 convert_to_pointer (type, expr)
45 if (integer_zerop (expr))
47 expr = build_int_2 (0, 0);
48 TREE_TYPE (expr) = type;
52 switch (TREE_CODE (TREE_TYPE (expr)))
56 return build1 (NOP_EXPR, type, expr);
62 if (TYPE_PRECISION (TREE_TYPE (expr)) == POINTER_SIZE)
63 return build1 (CONVERT_EXPR, type, expr);
66 convert_to_pointer (type,
67 convert ((*lang_hooks.types.type_for_size)
68 (POINTER_SIZE, 0), expr));
71 error ("cannot convert to a pointer type");
72 return convert_to_pointer (type, integer_zero_node);
76 /* Avoid any floating point extensions from EXP. */
78 strip_float_extensions (exp)
83 /* For floating point constant look up the narrowest type that can hold
84 it properly and handle it like (type)(narrowest_type)constant.
85 This way we can optimize for instance a=a*2.0 where "a" is float
86 but 2.0 is double constant. */
87 if (TREE_CODE (exp) == REAL_CST)
92 orig = TREE_REAL_CST (exp);
93 if (TYPE_PRECISION (TREE_TYPE (exp)) > TYPE_PRECISION (float_type_node)
94 && exact_real_truncate (TYPE_MODE (float_type_node), &orig))
95 type = float_type_node;
96 else if (TYPE_PRECISION (TREE_TYPE (exp))
97 > TYPE_PRECISION (double_type_node)
98 && exact_real_truncate (TYPE_MODE (double_type_node), &orig))
99 type = double_type_node;
101 return build_real (type, real_value_truncate (TYPE_MODE (type), orig));
104 if (TREE_CODE (exp) != NOP_EXPR)
107 sub = TREE_OPERAND (exp, 0);
108 subt = TREE_TYPE (sub);
109 expt = TREE_TYPE (exp);
111 if (!FLOAT_TYPE_P (subt))
114 if (TYPE_PRECISION (subt) > TYPE_PRECISION (expt))
117 return strip_float_extensions (sub);
121 /* Convert EXPR to some floating-point type TYPE.
123 EXPR must be float, integer, or enumeral;
124 in other cases error is called. */
127 convert_to_real (type, expr)
130 tree itype = TREE_TYPE (expr);
132 /* Disable until we figure out how to decide whether the functions are
133 present in runtime. */
135 enum built_in_function fcode = builtin_mathfn_code (expr);
137 /* Convert (float)sqrt((double)x) where x is float into sqrtf(x) */
138 if ((fcode == BUILT_IN_SQRT
139 || fcode == BUILT_IN_SQRTL
140 || fcode == BUILT_IN_SIN
141 || fcode == BUILT_IN_SINL
142 || fcode == BUILT_IN_COS
143 || fcode == BUILT_IN_COSL
144 || fcode == BUILT_IN_EXP
145 || fcode == BUILT_IN_EXPL)
147 && (TYPE_MODE (type) == TYPE_MODE (double_type_node)
148 || TYPE_MODE (type) == TYPE_MODE (float_type_node)))
150 tree arg0 = strip_float_extensions (TREE_VALUE (TREE_OPERAND (expr, 1)));
153 /* We have (outertype)sqrt((innertype)x). Choose the wider mode from
154 the both as the safe type for operation. */
155 if (TYPE_PRECISION (TREE_TYPE (arg0)) > TYPE_PRECISION (type))
156 newtype = TREE_TYPE (arg0);
158 /* Be curefull about integer to fp conversions.
159 These may overflow still. */
160 if (FLOAT_TYPE_P (TREE_TYPE (arg0))
161 && TYPE_PRECISION (newtype) <= TYPE_PRECISION (itype)
162 && (TYPE_MODE (newtype) == TYPE_MODE (double_type_node)
163 || TYPE_MODE (newtype) == TYPE_MODE (float_type_node)))
166 if (TYPE_MODE (type) == TYPE_MODE (float_type_node))
171 fcode = BUILT_IN_SQRTF;
175 fcode = BUILT_IN_SINF;
179 fcode = BUILT_IN_COSF;
183 fcode = BUILT_IN_EXPF;
193 fcode = BUILT_IN_SQRT;
197 fcode = BUILT_IN_SIN;
201 fcode = BUILT_IN_COS;
205 fcode = BUILT_IN_EXP;
211 /* ??? Fortran frontend does not initialize built_in_decls.
212 For some reason creating the decl using builtin_function does not
213 work as it should. */
214 if (built_in_decls [fcode])
216 arglist = build_tree_list (NULL_TREE, fold (convert_to_real (newtype, arg0)));
217 expr = build_function_call_expr (built_in_decls [fcode], arglist);
225 /* Propagate the cast into the operation. */
226 if (itype != type && FLOAT_TYPE_P (type))
227 switch (TREE_CODE (expr))
229 /* convert (float)-x into -(float)x. This is always safe. */
232 return build1 (TREE_CODE (expr), type,
233 fold (convert_to_real (type,
234 TREE_OPERAND (expr, 0))));
235 /* convert (outertype)((innertype0)a+(innertype1)b)
236 into ((newtype)a+(newtype)b) where newtype
237 is the widest mode from all of these. */
243 tree arg0 = strip_float_extensions (TREE_OPERAND (expr, 0));
244 tree arg1 = strip_float_extensions (TREE_OPERAND (expr, 1));
246 if (FLOAT_TYPE_P (TREE_TYPE (arg0))
247 && FLOAT_TYPE_P (TREE_TYPE (arg1)))
250 if (TYPE_PRECISION (TREE_TYPE (arg0)) > TYPE_PRECISION (newtype))
251 newtype = TREE_TYPE (arg0);
252 if (TYPE_PRECISION (TREE_TYPE (arg1)) > TYPE_PRECISION (newtype))
253 newtype = TREE_TYPE (arg1);
254 if (TYPE_PRECISION (newtype) < TYPE_PRECISION (itype))
256 expr = build (TREE_CODE (expr), newtype,
257 fold (convert_to_real (newtype, arg0)),
258 fold (convert_to_real (newtype, arg1)));
269 switch (TREE_CODE (TREE_TYPE (expr)))
272 return build1 (flag_float_store ? CONVERT_EXPR : NOP_EXPR,
279 return build1 (FLOAT_EXPR, type, expr);
282 return convert (type,
283 fold (build1 (REALPART_EXPR,
284 TREE_TYPE (TREE_TYPE (expr)), expr)));
288 error ("pointer value used where a floating point value was expected");
289 return convert_to_real (type, integer_zero_node);
292 error ("aggregate value used where a float was expected");
293 return convert_to_real (type, integer_zero_node);
297 /* Convert EXPR to some integer (or enum) type TYPE.
299 EXPR must be pointer, integer, discrete (enum, char, or bool), float, or
300 vector; in other cases error is called.
302 The result of this is always supposed to be a newly created tree node
303 not in use in any existing structure. */
306 convert_to_integer (type, expr)
309 enum tree_code ex_form = TREE_CODE (expr);
310 tree intype = TREE_TYPE (expr);
311 unsigned int inprec = TYPE_PRECISION (intype);
312 unsigned int outprec = TYPE_PRECISION (type);
314 /* An INTEGER_TYPE cannot be incomplete, but an ENUMERAL_TYPE can
315 be. Consider `enum E = { a, b = (enum E) 3 };'. */
316 if (!COMPLETE_TYPE_P (type))
318 error ("conversion to incomplete type");
319 return error_mark_node;
322 switch (TREE_CODE (intype))
326 if (integer_zerop (expr))
327 expr = integer_zero_node;
329 expr = fold (build1 (CONVERT_EXPR, (*lang_hooks.types.type_for_size)
330 (POINTER_SIZE, 0), expr));
332 return convert_to_integer (type, expr);
338 /* If this is a logical operation, which just returns 0 or 1, we can
339 change the type of the expression. For some logical operations,
340 we must also change the types of the operands to maintain type
343 if (TREE_CODE_CLASS (ex_form) == '<')
345 TREE_TYPE (expr) = type;
349 else if (ex_form == TRUTH_AND_EXPR || ex_form == TRUTH_ANDIF_EXPR
350 || ex_form == TRUTH_OR_EXPR || ex_form == TRUTH_ORIF_EXPR
351 || ex_form == TRUTH_XOR_EXPR)
353 TREE_OPERAND (expr, 0) = convert (type, TREE_OPERAND (expr, 0));
354 TREE_OPERAND (expr, 1) = convert (type, TREE_OPERAND (expr, 1));
355 TREE_TYPE (expr) = type;
359 else if (ex_form == TRUTH_NOT_EXPR)
361 TREE_OPERAND (expr, 0) = convert (type, TREE_OPERAND (expr, 0));
362 TREE_TYPE (expr) = type;
366 /* If we are widening the type, put in an explicit conversion.
367 Similarly if we are not changing the width. After this, we know
368 we are truncating EXPR. */
370 else if (outprec >= inprec)
371 return build1 (NOP_EXPR, type, expr);
373 /* If TYPE is an enumeral type or a type with a precision less
374 than the number of bits in its mode, do the conversion to the
375 type corresponding to its mode, then do a nop conversion
377 else if (TREE_CODE (type) == ENUMERAL_TYPE
378 || outprec != GET_MODE_BITSIZE (TYPE_MODE (type)))
379 return build1 (NOP_EXPR, type,
380 convert ((*lang_hooks.types.type_for_mode)
381 (TYPE_MODE (type), TREE_UNSIGNED (type)),
384 /* Here detect when we can distribute the truncation down past some
385 arithmetic. For example, if adding two longs and converting to an
386 int, we can equally well convert both to ints and then add.
387 For the operations handled here, such truncation distribution
389 It is desirable in these cases:
390 1) when truncating down to full-word from a larger size
391 2) when truncating takes no work.
392 3) when at least one operand of the arithmetic has been extended
393 (as by C's default conversions). In this case we need two conversions
394 if we do the arithmetic as already requested, so we might as well
395 truncate both and then combine. Perhaps that way we need only one.
397 Note that in general we cannot do the arithmetic in a type
398 shorter than the desired result of conversion, even if the operands
399 are both extended from a shorter type, because they might overflow
400 if combined in that type. The exceptions to this--the times when
401 two narrow values can be combined in their narrow type even to
402 make a wider result--are handled by "shorten" in build_binary_op. */
407 /* We can pass truncation down through right shifting
408 when the shift count is a nonpositive constant. */
409 if (TREE_CODE (TREE_OPERAND (expr, 1)) == INTEGER_CST
410 && tree_int_cst_lt (TREE_OPERAND (expr, 1),
411 convert (TREE_TYPE (TREE_OPERAND (expr, 1)),
417 /* We can pass truncation down through left shifting
418 when the shift count is a nonnegative constant and
419 the target type is unsigned. */
420 if (TREE_CODE (TREE_OPERAND (expr, 1)) == INTEGER_CST
421 && tree_int_cst_sgn (TREE_OPERAND (expr, 1)) >= 0
422 && TREE_UNSIGNED (type)
423 && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST)
425 /* If shift count is less than the width of the truncated type,
427 if (tree_int_cst_lt (TREE_OPERAND (expr, 1), TYPE_SIZE (type)))
428 /* In this case, shifting is like multiplication. */
432 /* If it is >= that width, result is zero.
433 Handling this with trunc1 would give the wrong result:
434 (int) ((long long) a << 32) is well defined (as 0)
435 but (int) a << 32 is undefined and would get a
438 tree t = convert_to_integer (type, integer_zero_node);
440 /* If the original expression had side-effects, we must
442 if (TREE_SIDE_EFFECTS (expr))
443 return build (COMPOUND_EXPR, type, expr, t);
454 tree arg0 = get_unwidened (TREE_OPERAND (expr, 0), type);
455 tree arg1 = get_unwidened (TREE_OPERAND (expr, 1), type);
457 /* Don't distribute unless the output precision is at least as big
458 as the actual inputs. Otherwise, the comparison of the
459 truncated values will be wrong. */
460 if (outprec >= TYPE_PRECISION (TREE_TYPE (arg0))
461 && outprec >= TYPE_PRECISION (TREE_TYPE (arg1))
462 /* If signedness of arg0 and arg1 don't match,
463 we can't necessarily find a type to compare them in. */
464 && (TREE_UNSIGNED (TREE_TYPE (arg0))
465 == TREE_UNSIGNED (TREE_TYPE (arg1))))
478 tree arg0 = get_unwidened (TREE_OPERAND (expr, 0), type);
479 tree arg1 = get_unwidened (TREE_OPERAND (expr, 1), type);
481 if (outprec >= BITS_PER_WORD
482 || TRULY_NOOP_TRUNCATION (outprec, inprec)
483 || inprec > TYPE_PRECISION (TREE_TYPE (arg0))
484 || inprec > TYPE_PRECISION (TREE_TYPE (arg1)))
486 /* Do the arithmetic in type TYPEX,
487 then convert result to TYPE. */
490 /* Can't do arithmetic in enumeral types
491 so use an integer type that will hold the values. */
492 if (TREE_CODE (typex) == ENUMERAL_TYPE)
493 typex = (*lang_hooks.types.type_for_size)
494 (TYPE_PRECISION (typex), TREE_UNSIGNED (typex));
496 /* But now perhaps TYPEX is as wide as INPREC.
497 In that case, do nothing special here.
498 (Otherwise would recurse infinitely in convert. */
499 if (TYPE_PRECISION (typex) != inprec)
501 /* Don't do unsigned arithmetic where signed was wanted,
503 Exception: if both of the original operands were
504 unsigned then we can safely do the work as unsigned.
505 Exception: shift operations take their type solely
506 from the first argument.
507 Exception: the LSHIFT_EXPR case above requires that
508 we perform this operation unsigned lest we produce
509 signed-overflow undefinedness.
510 And we may need to do it as unsigned
511 if we truncate to the original size. */
512 if (TREE_UNSIGNED (TREE_TYPE (expr))
513 || (TREE_UNSIGNED (TREE_TYPE (arg0))
514 && (TREE_UNSIGNED (TREE_TYPE (arg1))
515 || ex_form == LSHIFT_EXPR
516 || ex_form == RSHIFT_EXPR
517 || ex_form == LROTATE_EXPR
518 || ex_form == RROTATE_EXPR))
519 || ex_form == LSHIFT_EXPR)
520 typex = (*lang_hooks.types.unsigned_type) (typex);
522 typex = (*lang_hooks.types.signed_type) (typex);
523 return convert (type,
524 fold (build (ex_form, typex,
525 convert (typex, arg0),
526 convert (typex, arg1),
535 /* This is not correct for ABS_EXPR,
536 since we must test the sign before truncation. */
540 /* Can't do arithmetic in enumeral types
541 so use an integer type that will hold the values. */
542 if (TREE_CODE (typex) == ENUMERAL_TYPE)
543 typex = (*lang_hooks.types.type_for_size)
544 (TYPE_PRECISION (typex), TREE_UNSIGNED (typex));
546 /* But now perhaps TYPEX is as wide as INPREC.
547 In that case, do nothing special here.
548 (Otherwise would recurse infinitely in convert. */
549 if (TYPE_PRECISION (typex) != inprec)
551 /* Don't do unsigned arithmetic where signed was wanted,
553 if (TREE_UNSIGNED (TREE_TYPE (expr)))
554 typex = (*lang_hooks.types.unsigned_type) (typex);
556 typex = (*lang_hooks.types.signed_type) (typex);
557 return convert (type,
558 fold (build1 (ex_form, typex,
560 TREE_OPERAND (expr, 0)))));
566 "can't convert between vector values of different size" error. */
567 if (TREE_CODE (TREE_TYPE (TREE_OPERAND (expr, 0))) == VECTOR_TYPE
568 && (GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (TREE_OPERAND (expr, 0))))
569 != GET_MODE_SIZE (TYPE_MODE (type))))
571 /* If truncating after truncating, might as well do all at once.
572 If truncating after extending, we may get rid of wasted work. */
573 return convert (type, get_unwidened (TREE_OPERAND (expr, 0), type));
576 /* It is sometimes worthwhile to push the narrowing down through
577 the conditional and never loses. */
578 return fold (build (COND_EXPR, type, TREE_OPERAND (expr, 0),
579 convert (type, TREE_OPERAND (expr, 1)),
580 convert (type, TREE_OPERAND (expr, 2))));
586 return build1 (NOP_EXPR, type, expr);
589 return build1 (FIX_TRUNC_EXPR, type, expr);
592 return convert (type,
593 fold (build1 (REALPART_EXPR,
594 TREE_TYPE (TREE_TYPE (expr)), expr)));
597 if (GET_MODE_SIZE (TYPE_MODE (type))
598 != GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (expr))))
600 error ("can't convert between vector values of different size");
601 return error_mark_node;
603 return build1 (NOP_EXPR, type, expr);
606 error ("aggregate value used where an integer was expected");
607 return convert (type, integer_zero_node);
611 /* Convert EXPR to the complex type TYPE in the usual ways. */
614 convert_to_complex (type, expr)
617 tree subtype = TREE_TYPE (type);
619 switch (TREE_CODE (TREE_TYPE (expr)))
626 return build (COMPLEX_EXPR, type, convert (subtype, expr),
627 convert (subtype, integer_zero_node));
631 tree elt_type = TREE_TYPE (TREE_TYPE (expr));
633 if (TYPE_MAIN_VARIANT (elt_type) == TYPE_MAIN_VARIANT (subtype))
635 else if (TREE_CODE (expr) == COMPLEX_EXPR)
636 return fold (build (COMPLEX_EXPR,
638 convert (subtype, TREE_OPERAND (expr, 0)),
639 convert (subtype, TREE_OPERAND (expr, 1))));
642 expr = save_expr (expr);
644 fold (build (COMPLEX_EXPR,
645 type, convert (subtype,
646 fold (build1 (REALPART_EXPR,
647 TREE_TYPE (TREE_TYPE (expr)),
650 fold (build1 (IMAGPART_EXPR,
651 TREE_TYPE (TREE_TYPE (expr)),
658 error ("pointer value used where a complex was expected");
659 return convert_to_complex (type, integer_zero_node);
662 error ("aggregate value used where a complex was expected");
663 return convert_to_complex (type, integer_zero_node);
667 /* Convert EXPR to the vector type TYPE in the usual ways. */
670 convert_to_vector (type, expr)
673 switch (TREE_CODE (TREE_TYPE (expr)))
677 if (GET_MODE_SIZE (TYPE_MODE (type))
678 != GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (expr))))
680 error ("can't convert between vector values of different size");
681 return error_mark_node;
683 return build1 (NOP_EXPR, type, expr);
686 error ("can't convert value to a vector");
687 return convert_to_vector (type, integer_zero_node);