1 /* Utility routines for data type conversion for GCC.
2 Copyright (C) 1987, 1988, 1991, 1992, 1993, 1994, 1995, 1997, 1998,
3 2000, 2001, 2002, 2003, 2004 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 (tree type, tree expr)
44 if (integer_zerop (expr))
46 expr = build_int_2 (0, 0);
47 TREE_TYPE (expr) = type;
51 switch (TREE_CODE (TREE_TYPE (expr)))
55 return build1 (NOP_EXPR, type, expr);
61 if (TYPE_PRECISION (TREE_TYPE (expr)) == POINTER_SIZE)
62 return build1 (CONVERT_EXPR, type, expr);
65 convert_to_pointer (type,
66 convert (lang_hooks.types.type_for_size
67 (POINTER_SIZE, 0), expr));
70 error ("cannot convert to a pointer type");
71 return convert_to_pointer (type, integer_zero_node);
75 /* Avoid any floating point extensions from EXP. */
77 strip_float_extensions (tree exp)
81 /* For floating point constant look up the narrowest type that can hold
82 it properly and handle it like (type)(narrowest_type)constant.
83 This way we can optimize for instance a=a*2.0 where "a" is float
84 but 2.0 is double constant. */
85 if (TREE_CODE (exp) == REAL_CST)
90 orig = TREE_REAL_CST (exp);
91 if (TYPE_PRECISION (TREE_TYPE (exp)) > TYPE_PRECISION (float_type_node)
92 && exact_real_truncate (TYPE_MODE (float_type_node), &orig))
93 type = float_type_node;
94 else if (TYPE_PRECISION (TREE_TYPE (exp))
95 > TYPE_PRECISION (double_type_node)
96 && exact_real_truncate (TYPE_MODE (double_type_node), &orig))
97 type = double_type_node;
99 return build_real (type, real_value_truncate (TYPE_MODE (type), orig));
102 if (TREE_CODE (exp) != NOP_EXPR)
105 sub = TREE_OPERAND (exp, 0);
106 subt = TREE_TYPE (sub);
107 expt = TREE_TYPE (exp);
109 if (!FLOAT_TYPE_P (subt))
112 if (TYPE_PRECISION (subt) > TYPE_PRECISION (expt))
115 return strip_float_extensions (sub);
119 /* Convert EXPR to some floating-point type TYPE.
121 EXPR must be float, integer, or enumeral;
122 in other cases error is called. */
125 convert_to_real (tree type, tree expr)
127 enum built_in_function fcode = builtin_mathfn_code (expr);
128 tree itype = TREE_TYPE (expr);
130 /* Disable until we figure out how to decide whether the functions are
131 present in runtime. */
132 /* Convert (float)sqrt((double)x) where x is float into sqrtf(x) */
134 && (TYPE_MODE (type) == TYPE_MODE (double_type_node)
135 || TYPE_MODE (type) == TYPE_MODE (float_type_node)))
139 #define CASE_MATHFN(FN) case BUILT_IN_##FN: case BUILT_IN_##FN##L:
176 tree arg0 = strip_float_extensions (TREE_VALUE (TREE_OPERAND (expr, 1)));
179 /* We have (outertype)sqrt((innertype)x). Choose the wider mode from
180 the both as the safe type for operation. */
181 if (TYPE_PRECISION (TREE_TYPE (arg0)) > TYPE_PRECISION (type))
182 newtype = TREE_TYPE (arg0);
184 /* Be careful about integer to fp conversions.
185 These may overflow still. */
186 if (FLOAT_TYPE_P (TREE_TYPE (arg0))
187 && TYPE_PRECISION (newtype) < TYPE_PRECISION (itype)
188 && (TYPE_MODE (newtype) == TYPE_MODE (double_type_node)
189 || TYPE_MODE (newtype) == TYPE_MODE (float_type_node)))
192 tree fn = mathfn_built_in (newtype, fcode);
196 arglist = build_tree_list (NULL_TREE, fold (convert_to_real (newtype, arg0)));
197 expr = build_function_call_expr (fn, arglist);
208 && (((fcode == BUILT_IN_FLOORL
209 || fcode == BUILT_IN_CEILL
210 || fcode == BUILT_IN_ROUNDL
211 || fcode == BUILT_IN_RINTL
212 || fcode == BUILT_IN_TRUNCL
213 || fcode == BUILT_IN_NEARBYINTL)
214 && (TYPE_MODE (type) == TYPE_MODE (double_type_node)
215 || TYPE_MODE (type) == TYPE_MODE (float_type_node)))
216 || ((fcode == BUILT_IN_FLOOR
217 || fcode == BUILT_IN_CEIL
218 || fcode == BUILT_IN_ROUND
219 || fcode == BUILT_IN_RINT
220 || fcode == BUILT_IN_TRUNC
221 || fcode == BUILT_IN_NEARBYINT)
222 && (TYPE_MODE (type) == TYPE_MODE (float_type_node)))))
224 tree fn = mathfn_built_in (type, fcode);
228 tree arg0 = strip_float_extensions (TREE_VALUE (TREE_OPERAND (expr,
230 tree arglist = build_tree_list (NULL_TREE,
231 fold (convert_to_real (type, arg0)));
233 return build_function_call_expr (fn, arglist);
237 /* Propagate the cast into the operation. */
238 if (itype != type && FLOAT_TYPE_P (type))
239 switch (TREE_CODE (expr))
241 /* Convert (float)-x into -(float)x. This is always safe. */
244 if (TYPE_PRECISION (type) < TYPE_PRECISION (TREE_TYPE (expr)))
245 return build1 (TREE_CODE (expr), type,
246 fold (convert_to_real (type,
247 TREE_OPERAND (expr, 0))));
249 /* Convert (outertype)((innertype0)a+(innertype1)b)
250 into ((newtype)a+(newtype)b) where newtype
251 is the widest mode from all of these. */
257 tree arg0 = strip_float_extensions (TREE_OPERAND (expr, 0));
258 tree arg1 = strip_float_extensions (TREE_OPERAND (expr, 1));
260 if (FLOAT_TYPE_P (TREE_TYPE (arg0))
261 && FLOAT_TYPE_P (TREE_TYPE (arg1)))
264 if (TYPE_PRECISION (TREE_TYPE (arg0)) > TYPE_PRECISION (newtype))
265 newtype = TREE_TYPE (arg0);
266 if (TYPE_PRECISION (TREE_TYPE (arg1)) > TYPE_PRECISION (newtype))
267 newtype = TREE_TYPE (arg1);
268 if (TYPE_PRECISION (newtype) < TYPE_PRECISION (itype))
270 expr = build (TREE_CODE (expr), newtype,
271 fold (convert_to_real (newtype, arg0)),
272 fold (convert_to_real (newtype, arg1)));
283 switch (TREE_CODE (TREE_TYPE (expr)))
286 return build1 (flag_float_store ? CONVERT_EXPR : NOP_EXPR,
293 return build1 (FLOAT_EXPR, type, expr);
296 return convert (type,
297 fold (build1 (REALPART_EXPR,
298 TREE_TYPE (TREE_TYPE (expr)), expr)));
302 error ("pointer value used where a floating point value was expected");
303 return convert_to_real (type, integer_zero_node);
306 error ("aggregate value used where a float was expected");
307 return convert_to_real (type, integer_zero_node);
311 /* Convert EXPR to some integer (or enum) type TYPE.
313 EXPR must be pointer, integer, discrete (enum, char, or bool), float, or
314 vector; in other cases error is called.
316 The result of this is always supposed to be a newly created tree node
317 not in use in any existing structure. */
320 convert_to_integer (tree type, tree expr)
322 enum tree_code ex_form = TREE_CODE (expr);
323 tree intype = TREE_TYPE (expr);
324 unsigned int inprec = TYPE_PRECISION (intype);
325 unsigned int outprec = TYPE_PRECISION (type);
327 /* An INTEGER_TYPE cannot be incomplete, but an ENUMERAL_TYPE can
328 be. Consider `enum E = { a, b = (enum E) 3 };'. */
329 if (!COMPLETE_TYPE_P (type))
331 error ("conversion to incomplete type");
332 return error_mark_node;
335 /* Convert e.g. (long)round(d) -> lround(d). */
336 /* If we're converting to char, we may encounter differing behavior
337 between converting from double->char vs double->long->char.
338 We're in "undefined" territory but we prefer to be conservative,
339 so only proceed in "unsafe" math mode. */
341 && (flag_unsafe_math_optimizations
342 || outprec >= TYPE_PRECISION (long_integer_type_node)))
344 tree s_expr = strip_float_extensions (expr);
345 tree s_intype = TREE_TYPE (s_expr);
346 const enum built_in_function fcode = builtin_mathfn_code (s_expr);
351 case BUILT_IN_ROUND: case BUILT_IN_ROUNDF: case BUILT_IN_ROUNDL:
352 if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (long_long_integer_type_node))
353 fn = mathfn_built_in (s_intype, BUILT_IN_LLROUND);
355 fn = mathfn_built_in (s_intype, BUILT_IN_LROUND);
358 case BUILT_IN_RINT: case BUILT_IN_RINTF: case BUILT_IN_RINTL:
359 /* Only convert rint* if we can ignore math exceptions. */
360 if (flag_trapping_math)
362 /* ... Fall through ... */
363 case BUILT_IN_NEARBYINT: case BUILT_IN_NEARBYINTF: case BUILT_IN_NEARBYINTL:
364 if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (long_long_integer_type_node))
365 fn = mathfn_built_in (s_intype, BUILT_IN_LLRINT);
367 fn = mathfn_built_in (s_intype, BUILT_IN_LRINT);
375 tree arglist = TREE_OPERAND (s_expr, 1);
376 tree newexpr = build_function_call_expr (fn, arglist);
377 return convert_to_integer (type, newexpr);
381 switch (TREE_CODE (intype))
385 if (integer_zerop (expr))
386 expr = integer_zero_node;
388 expr = fold (build1 (CONVERT_EXPR,
389 lang_hooks.types.type_for_size (POINTER_SIZE, 0),
392 return convert_to_integer (type, expr);
398 /* If this is a logical operation, which just returns 0 or 1, we can
399 change the type of the expression. For some logical operations,
400 we must also change the types of the operands to maintain type
403 if (TREE_CODE_CLASS (ex_form) == '<')
405 expr = copy_node (expr);
406 TREE_TYPE (expr) = type;
410 else if (ex_form == TRUTH_AND_EXPR || ex_form == TRUTH_ANDIF_EXPR
411 || ex_form == TRUTH_OR_EXPR || ex_form == TRUTH_ORIF_EXPR
412 || ex_form == TRUTH_XOR_EXPR)
414 expr = copy_node (expr);
415 TREE_OPERAND (expr, 0) = convert (type, TREE_OPERAND (expr, 0));
416 TREE_OPERAND (expr, 1) = convert (type, TREE_OPERAND (expr, 1));
417 TREE_TYPE (expr) = type;
421 else if (ex_form == TRUTH_NOT_EXPR)
423 expr = copy_node (expr);
424 TREE_OPERAND (expr, 0) = convert (type, TREE_OPERAND (expr, 0));
425 TREE_TYPE (expr) = type;
429 /* If we are widening the type, put in an explicit conversion.
430 Similarly if we are not changing the width. After this, we know
431 we are truncating EXPR. */
433 else if (outprec >= inprec)
437 /* If the precision of the EXPR's type is K bits and the
438 destination mode has more bits, and the sign is changing,
439 it is not safe to use a NOP_EXPR. For example, suppose
440 that EXPR's type is a 3-bit unsigned integer type, the
441 TYPE is a 3-bit signed integer type, and the machine mode
442 for the types is 8-bit QImode. In that case, the
443 conversion necessitates an explicit sign-extension. In
444 the signed-to-unsigned case the high-order bits have to
446 if (TYPE_UNSIGNED (type) != TYPE_UNSIGNED (TREE_TYPE (expr))
447 && (TYPE_PRECISION (TREE_TYPE (expr))
448 != GET_MODE_BITSIZE (TYPE_MODE (TREE_TYPE (expr)))))
453 return build1 (code, type, expr);
456 /* If TYPE is an enumeral type or a type with a precision less
457 than the number of bits in its mode, do the conversion to the
458 type corresponding to its mode, then do a nop conversion
460 else if (TREE_CODE (type) == ENUMERAL_TYPE
461 || outprec != GET_MODE_BITSIZE (TYPE_MODE (type)))
462 return build1 (NOP_EXPR, type,
463 convert (lang_hooks.types.type_for_mode
464 (TYPE_MODE (type), TYPE_UNSIGNED (type)),
467 /* Here detect when we can distribute the truncation down past some
468 arithmetic. For example, if adding two longs and converting to an
469 int, we can equally well convert both to ints and then add.
470 For the operations handled here, such truncation distribution
472 It is desirable in these cases:
473 1) when truncating down to full-word from a larger size
474 2) when truncating takes no work.
475 3) when at least one operand of the arithmetic has been extended
476 (as by C's default conversions). In this case we need two conversions
477 if we do the arithmetic as already requested, so we might as well
478 truncate both and then combine. Perhaps that way we need only one.
480 Note that in general we cannot do the arithmetic in a type
481 shorter than the desired result of conversion, even if the operands
482 are both extended from a shorter type, because they might overflow
483 if combined in that type. The exceptions to this--the times when
484 two narrow values can be combined in their narrow type even to
485 make a wider result--are handled by "shorten" in build_binary_op. */
490 /* We can pass truncation down through right shifting
491 when the shift count is a nonpositive constant. */
492 if (TREE_CODE (TREE_OPERAND (expr, 1)) == INTEGER_CST
493 && tree_int_cst_lt (TREE_OPERAND (expr, 1),
494 convert (TREE_TYPE (TREE_OPERAND (expr, 1)),
500 /* We can pass truncation down through left shifting
501 when the shift count is a nonnegative constant and
502 the target type is unsigned. */
503 if (TREE_CODE (TREE_OPERAND (expr, 1)) == INTEGER_CST
504 && tree_int_cst_sgn (TREE_OPERAND (expr, 1)) >= 0
505 && TYPE_UNSIGNED (type)
506 && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST)
508 /* If shift count is less than the width of the truncated type,
510 if (tree_int_cst_lt (TREE_OPERAND (expr, 1), TYPE_SIZE (type)))
511 /* In this case, shifting is like multiplication. */
515 /* If it is >= that width, result is zero.
516 Handling this with trunc1 would give the wrong result:
517 (int) ((long long) a << 32) is well defined (as 0)
518 but (int) a << 32 is undefined and would get a
521 tree t = convert_to_integer (type, integer_zero_node);
523 /* If the original expression had side-effects, we must
525 if (TREE_SIDE_EFFECTS (expr))
526 return build (COMPOUND_EXPR, type, expr, t);
537 tree arg0 = get_unwidened (TREE_OPERAND (expr, 0), type);
538 tree arg1 = get_unwidened (TREE_OPERAND (expr, 1), type);
540 /* Don't distribute unless the output precision is at least as big
541 as the actual inputs. Otherwise, the comparison of the
542 truncated values will be wrong. */
543 if (outprec >= TYPE_PRECISION (TREE_TYPE (arg0))
544 && outprec >= TYPE_PRECISION (TREE_TYPE (arg1))
545 /* If signedness of arg0 and arg1 don't match,
546 we can't necessarily find a type to compare them in. */
547 && (TYPE_UNSIGNED (TREE_TYPE (arg0))
548 == TYPE_UNSIGNED (TREE_TYPE (arg1))))
560 tree arg0 = get_unwidened (TREE_OPERAND (expr, 0), type);
561 tree arg1 = get_unwidened (TREE_OPERAND (expr, 1), type);
563 if (outprec >= BITS_PER_WORD
564 || TRULY_NOOP_TRUNCATION (outprec, inprec)
565 || inprec > TYPE_PRECISION (TREE_TYPE (arg0))
566 || inprec > TYPE_PRECISION (TREE_TYPE (arg1)))
568 /* Do the arithmetic in type TYPEX,
569 then convert result to TYPE. */
572 /* Can't do arithmetic in enumeral types
573 so use an integer type that will hold the values. */
574 if (TREE_CODE (typex) == ENUMERAL_TYPE)
575 typex = lang_hooks.types.type_for_size
576 (TYPE_PRECISION (typex), TYPE_UNSIGNED (typex));
578 /* But now perhaps TYPEX is as wide as INPREC.
579 In that case, do nothing special here.
580 (Otherwise would recurse infinitely in convert. */
581 if (TYPE_PRECISION (typex) != inprec)
583 /* Don't do unsigned arithmetic where signed was wanted,
585 Exception: if both of the original operands were
586 unsigned then we can safely do the work as unsigned.
587 Exception: shift operations take their type solely
588 from the first argument.
589 Exception: the LSHIFT_EXPR case above requires that
590 we perform this operation unsigned lest we produce
591 signed-overflow undefinedness.
592 And we may need to do it as unsigned
593 if we truncate to the original size. */
594 if (TYPE_UNSIGNED (TREE_TYPE (expr))
595 || (TYPE_UNSIGNED (TREE_TYPE (arg0))
596 && (TYPE_UNSIGNED (TREE_TYPE (arg1))
597 || ex_form == LSHIFT_EXPR
598 || ex_form == RSHIFT_EXPR
599 || ex_form == LROTATE_EXPR
600 || ex_form == RROTATE_EXPR))
601 || ex_form == LSHIFT_EXPR)
602 typex = lang_hooks.types.unsigned_type (typex);
604 typex = lang_hooks.types.signed_type (typex);
605 return convert (type,
606 fold (build (ex_form, typex,
607 convert (typex, arg0),
608 convert (typex, arg1))));
616 /* This is not correct for ABS_EXPR,
617 since we must test the sign before truncation. */
621 /* Can't do arithmetic in enumeral types
622 so use an integer type that will hold the values. */
623 if (TREE_CODE (typex) == ENUMERAL_TYPE)
624 typex = lang_hooks.types.type_for_size
625 (TYPE_PRECISION (typex), TYPE_UNSIGNED (typex));
627 /* But now perhaps TYPEX is as wide as INPREC.
628 In that case, do nothing special here.
629 (Otherwise would recurse infinitely in convert. */
630 if (TYPE_PRECISION (typex) != inprec)
632 /* Don't do unsigned arithmetic where signed was wanted,
634 if (TYPE_UNSIGNED (TREE_TYPE (expr)))
635 typex = lang_hooks.types.unsigned_type (typex);
637 typex = lang_hooks.types.signed_type (typex);
638 return convert (type,
639 fold (build1 (ex_form, typex,
641 TREE_OPERAND (expr, 0)))));
647 "can't convert between vector values of different size" error. */
648 if (TREE_CODE (TREE_TYPE (TREE_OPERAND (expr, 0))) == VECTOR_TYPE
649 && (GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (TREE_OPERAND (expr, 0))))
650 != GET_MODE_SIZE (TYPE_MODE (type))))
652 /* If truncating after truncating, might as well do all at once.
653 If truncating after extending, we may get rid of wasted work. */
654 return convert (type, get_unwidened (TREE_OPERAND (expr, 0), type));
657 /* It is sometimes worthwhile to push the narrowing down through
658 the conditional and never loses. */
659 return fold (build (COND_EXPR, type, TREE_OPERAND (expr, 0),
660 convert (type, TREE_OPERAND (expr, 1)),
661 convert (type, TREE_OPERAND (expr, 2))));
667 return build1 (NOP_EXPR, type, expr);
670 return build1 (FIX_TRUNC_EXPR, type, expr);
673 return convert (type,
674 fold (build1 (REALPART_EXPR,
675 TREE_TYPE (TREE_TYPE (expr)), expr)));
678 if (GET_MODE_SIZE (TYPE_MODE (type))
679 != GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (expr))))
681 error ("can't convert between vector values of different size");
682 return error_mark_node;
684 return build1 (NOP_EXPR, type, expr);
687 error ("aggregate value used where an integer was expected");
688 return convert (type, integer_zero_node);
692 /* Convert EXPR to the complex type TYPE in the usual ways. */
695 convert_to_complex (tree type, tree expr)
697 tree subtype = TREE_TYPE (type);
699 switch (TREE_CODE (TREE_TYPE (expr)))
706 return build (COMPLEX_EXPR, type, convert (subtype, expr),
707 convert (subtype, integer_zero_node));
711 tree elt_type = TREE_TYPE (TREE_TYPE (expr));
713 if (TYPE_MAIN_VARIANT (elt_type) == TYPE_MAIN_VARIANT (subtype))
715 else if (TREE_CODE (expr) == COMPLEX_EXPR)
716 return fold (build (COMPLEX_EXPR,
718 convert (subtype, TREE_OPERAND (expr, 0)),
719 convert (subtype, TREE_OPERAND (expr, 1))));
722 expr = save_expr (expr);
724 fold (build (COMPLEX_EXPR,
725 type, convert (subtype,
726 fold (build1 (REALPART_EXPR,
727 TREE_TYPE (TREE_TYPE (expr)),
730 fold (build1 (IMAGPART_EXPR,
731 TREE_TYPE (TREE_TYPE (expr)),
738 error ("pointer value used where a complex was expected");
739 return convert_to_complex (type, integer_zero_node);
742 error ("aggregate value used where a complex was expected");
743 return convert_to_complex (type, integer_zero_node);
747 /* Convert EXPR to the vector type TYPE in the usual ways. */
750 convert_to_vector (tree type, tree expr)
752 switch (TREE_CODE (TREE_TYPE (expr)))
756 if (GET_MODE_SIZE (TYPE_MODE (type))
757 != GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (expr))))
759 error ("can't convert between vector values of different size");
760 return error_mark_node;
762 return build1 (NOP_EXPR, type, expr);
765 error ("can't convert value to a vector");
766 return convert_to_vector (type, integer_zero_node);