egcs projects compiler system

Exact copy of the snapshot, except for the removal of
	texinfo/
	gcc/ch/
	libchill/

1 files changed, 444 insertions, 0 deletions

diff --git a/gnu/egcs/gcc/convert.c b/gnu/egcs/gcc/convert.c
new file mode 100644
index 00000000000..bfcb5db4470
--- /dev/null
+++ b/gnu/egcs/gcc/convert.c
@@ -0,0 +1,444 @@
+/* Utility routines for data type conversion for GNU C.
+   Copyright (C) 1987, 88, 91-95, 97, 1998 Free Software Foundation, Inc.
+
+This file is part of GNU C.
+
+GNU CC is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2, or (at your option)
+any later version.
+
+GNU CC is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU CC; see the file COPYING.  If not, write to
+the Free Software Foundation, 59 Temple Place - Suite 330,
+Boston, MA 02111-1307, USA.  */
+
+
+/* These routines are somewhat language-independent utility function
+   intended to be called by the language-specific convert () functions.  */
+
+#include "config.h"
+#include "tree.h"
+#include "flags.h"
+#include "convert.h"
+#include "toplev.h"
+
+/* Convert EXPR to some pointer or reference type TYPE.
+
+   EXPR must be pointer, reference, integer, enumeral, or literal zero;
+   in other cases error is called.  */
+
+tree
+convert_to_pointer (type, expr)
+     tree type, expr;
+{
+  if (integer_zerop (expr))
+    {
+      expr = build_int_2 (0, 0);
+      TREE_TYPE (expr) = type;
+      return expr;
+    }
+
+  switch (TREE_CODE (TREE_TYPE (expr)))
+    {
+    case POINTER_TYPE:
+    case REFERENCE_TYPE:
+      return build1 (NOP_EXPR, type, expr);
+
+    case INTEGER_TYPE:
+    case ENUMERAL_TYPE:
+    case BOOLEAN_TYPE:
+    case CHAR_TYPE:
+      if (TYPE_PRECISION (TREE_TYPE (expr)) == POINTER_SIZE)
+	return build1 (CONVERT_EXPR, type, expr);
+
+      return
+	convert_to_pointer (type,
+			    convert (type_for_size (POINTER_SIZE, 0), expr));
+
+    default:
+      error ("cannot convert to a pointer type");
+      return convert_to_pointer (type, integer_zero_node);
+    }
+}
+
+/* Convert EXPR to some floating-point type TYPE.
+
+   EXPR must be float, integer, or enumeral;
+   in other cases error is called.  */
+
+tree
+convert_to_real (type, expr)
+     tree type, expr;
+{
+  switch (TREE_CODE (TREE_TYPE (expr)))
+    {
+    case REAL_TYPE:
+      return build1 (flag_float_store ? CONVERT_EXPR : NOP_EXPR,
+		     type, expr);
+
+    case INTEGER_TYPE:
+    case ENUMERAL_TYPE:
+    case BOOLEAN_TYPE:
+    case CHAR_TYPE:
+      return build1 (FLOAT_EXPR, type, expr);
+
+    case COMPLEX_TYPE:
+      return convert (type,
+		      fold (build1 (REALPART_EXPR,
+				    TREE_TYPE (TREE_TYPE (expr)), expr)));
+
+    case POINTER_TYPE:
+    case REFERENCE_TYPE:
+      error ("pointer value used where a floating point value was expected");
+      return convert_to_real (type, integer_zero_node);
+
+    default:
+      error ("aggregate value used where a float was expected");
+      return convert_to_real (type, integer_zero_node);
+    }
+}
+
+/* Convert EXPR to some integer (or enum) type TYPE.
+
+   EXPR must be pointer, integer, discrete (enum, char, or bool), or float;
+   in other cases error is called.
+
+   The result of this is always supposed to be a newly created tree node
+   not in use in any existing structure.  */
+
+tree
+convert_to_integer (type, expr)
+     tree type, expr;
+{
+  enum tree_code ex_form = TREE_CODE (expr);
+  tree intype = TREE_TYPE (expr);
+  int inprec = TYPE_PRECISION (intype);
+  int outprec = TYPE_PRECISION (type);
+
+  /* An INTEGER_TYPE cannot be incomplete, but an ENUMERAL_TYPE can
+     be.  Consider `enum E = { a, b = (enum E) 3 };'.  */
+  if (!TYPE_SIZE (type))
+    {
+      error ("conversion to incomplete type");
+      return error_mark_node;
+    }
+
+  switch (TREE_CODE (intype))
+    {
+    case POINTER_TYPE:
+    case REFERENCE_TYPE:
+      if (integer_zerop (expr))
+	expr = integer_zero_node;
+      else
+	expr = fold (build1 (CONVERT_EXPR,
+			     type_for_size (POINTER_SIZE, 0), expr));
+
+      return convert_to_integer (type, expr);
+
+    case INTEGER_TYPE:
+    case ENUMERAL_TYPE:
+    case BOOLEAN_TYPE:
+    case CHAR_TYPE:
+      /* If this is a logical operation, which just returns 0 or 1, we can
+	 change the type of the expression.  For some logical operations,
+	 we must also change the types of the operands to maintain type
+	 correctness.  */
+
+      if (TREE_CODE_CLASS (ex_form) == '<')
+	{
+	  TREE_TYPE (expr) = type;
+	  return expr;
+	}
+
+      else if (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)
+	{
+	  TREE_OPERAND (expr, 0) = convert (type, TREE_OPERAND (expr, 0));
+	  TREE_OPERAND (expr, 1) = convert (type, TREE_OPERAND (expr, 1));
+	  TREE_TYPE (expr) = type;
+	  return expr;
+	}
+
+      else if (ex_form == TRUTH_NOT_EXPR)
+	{
+	  TREE_OPERAND (expr, 0) = convert (type, TREE_OPERAND (expr, 0));
+	  TREE_TYPE (expr) = type;
+	  return expr;
+	}
+
+      /* If we are widening the type, put in an explicit conversion.
+	 Similarly if we are not changing the width.  After this, we know
+	 we are truncating EXPR.  */
+
+      else if (outprec >= inprec)
+	return build1 (NOP_EXPR, type, expr);
+
+      /* If TYPE is an enumeral type or a type with a precision less
+	 than the number of bits in its mode, do the conversion to the
+	 type corresponding to its mode, then do a nop conversion
+	 to TYPE.  */
+      else if (TREE_CODE (type) == ENUMERAL_TYPE
+	       || outprec != GET_MODE_BITSIZE (TYPE_MODE (type)))
+	return build1 (NOP_EXPR, type,
+		       convert (type_for_mode (TYPE_MODE (type),
+					       TREE_UNSIGNED (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),
+				  convert (TREE_TYPE (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_sgn (TREE_OPERAND (expr, 1)) >= 0
+	      && 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.  */
+
+		  tree t = convert_to_integer (type, integer_zero_node);
+
+		  /* If the original expression had side-effects, we must
+		     preserve it.  */
+		  if (TREE_SIDE_EFFECTS (expr))
+		    return build (COMPOUND_EXPR, type, expr, t);
+		  else
+		    return t;
+		}
+	    }
+	  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,
+				    fold (build (ex_form, typex,
+						 convert (typex, arg0),
+						 convert (typex, arg1),
+						 0)));
+		  }
+	      }
+	  }
+	  break;
+
+	case NEGATE_EXPR:
+	case BIT_NOT_EXPR:
+	  /* This is not correct for ABS_EXPR,
+	     since we must test the sign before truncation.  */
+	  {
+	    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 (build1 (ex_form, typex,
+					      convert (typex,
+						       TREE_OPERAND (expr, 0)))));
+	      }
+	  }
+
+	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:
+	  /* It is sometimes worthwhile to push the narrowing down through
+	     the conditional and never loses.  */
+	  return fold (build (COND_EXPR, type, TREE_OPERAND (expr, 0),
+			      convert (type, TREE_OPERAND (expr, 1)), 
+			      convert (type, TREE_OPERAND (expr, 2))));
+
+	default:
+	  break;
+	}
+
+      return build1 (NOP_EXPR, type, expr);
+
+    case REAL_TYPE:
+      return build1 (FIX_TRUNC_EXPR, type, expr);
+
+    case COMPLEX_TYPE:
+      return convert (type,
+		      fold (build1 (REALPART_EXPR,
+				    TREE_TYPE (TREE_TYPE (expr)), expr)));
+
+    default:
+      error ("aggregate value used where an integer was expected");
+      return convert (type, integer_zero_node);
+    }
+}
+
+/* Convert EXPR to the complex type TYPE in the usual ways.  */
+
+tree
+convert_to_complex (type, expr)
+     tree type, expr;
+{
+  tree subtype = TREE_TYPE (type);
+  
+  switch (TREE_CODE (TREE_TYPE (expr)))
+    {
+    case REAL_TYPE:
+    case INTEGER_TYPE:
+    case ENUMERAL_TYPE:
+    case BOOLEAN_TYPE:
+    case CHAR_TYPE:
+      return build (COMPLEX_EXPR, type, convert (subtype, expr),
+		    convert (subtype, integer_zero_node));
+
+    case COMPLEX_TYPE:
+      {
+	tree elt_type = TREE_TYPE (TREE_TYPE (expr));
+
+	if (TYPE_MAIN_VARIANT (elt_type) == TYPE_MAIN_VARIANT (subtype))
+	  return expr;
+	else if (TREE_CODE (expr) == COMPLEX_EXPR)
+	  return fold (build (COMPLEX_EXPR,
+			      type,
+			      convert (subtype, TREE_OPERAND (expr, 0)),
+			      convert (subtype, TREE_OPERAND (expr, 1))));
+	else
+	  {
+	    expr = save_expr (expr);
+	    return
+	      fold (build (COMPLEX_EXPR,
+			   type, convert (subtype,
+					  fold (build1 (REALPART_EXPR,
+							TREE_TYPE (TREE_TYPE (expr)),
+							expr))),
+			   convert (subtype,
+				    fold (build1 (IMAGPART_EXPR,
+						  TREE_TYPE (TREE_TYPE (expr)),
+						  expr)))));
+	  }
+      }
+
+    case POINTER_TYPE:
+    case REFERENCE_TYPE:
+      error ("pointer value used where a complex was expected");
+      return convert_to_complex (type, integer_zero_node);
+
+    default:
+      error ("aggregate value used where a complex was expected");
+      return convert_to_complex (type, integer_zero_node);
+    }
+}