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msg_324.c revision 1.6 
      1  1.6  rillig /*	$NetBSD: msg_324.c,v 1.6 2022/06/17 06:59:16 rillig Exp $	*/
      2  1.1  rillig # 3 "msg_324.c"
      3  1.1  rillig 
      4  1.1  rillig // Test for message: suggest cast from '%s' to '%s' on op %s to avoid overflow [324]
      5  1.1  rillig 
      6  1.2  rillig /*
      7  1.2  rillig  * This warning applies to binary operators if the result of the operator
      8  1.2  rillig  * is converted to a type that is bigger than the operands' result type
      9  1.2  rillig  * after the usual arithmetic promotions.
     10  1.2  rillig  *
     11  1.2  rillig  * In such a case, the operator's result would be truncated to the operator's
     12  1.2  rillig  * result type (invoking undefined behavior for signed integers), and that
     13  1.2  rillig  * truncated value would then be converted.  At that point, a few bits may
     14  1.2  rillig  * have been lost.
     15  1.2  rillig  */
     16  1.2  rillig 
     17  1.2  rillig /* lint1-flags: -g -S -w -P */
     18  1.2  rillig 
     19  1.2  rillig void
     20  1.2  rillig example(char c, int i, unsigned u)
     21  1.2  rillig {
     22  1.4  rillig 	long long ll;
     23  1.4  rillig 	unsigned long long ull;
     24  1.2  rillig 
     25  1.6  rillig 	/* expect+1: warning: suggest cast from 'int' to 'long long' on op + to avoid overflow [324] */
     26  1.6  rillig 	ll = c + i;
     27  1.6  rillig 	/* expect+1: warning: suggest cast from 'int' to 'long long' on op - to avoid overflow [324] */
     28  1.6  rillig 	ll = i - c;
     29  1.6  rillig 	/* expect+1: warning: suggest cast from 'unsigned int' to 'unsigned long long' on op * to avoid overflow [324] */
     30  1.6  rillig 	ull = c * u;
     31  1.6  rillig 	/* expect+1: warning: suggest cast from 'unsigned int' to 'unsigned long long' on op + to avoid overflow [324] */
     32  1.6  rillig 	ull = u + c;
     33  1.6  rillig 	/* expect+1: warning: suggest cast from 'unsigned int' to 'unsigned long long' on op - to avoid overflow [324] */
     34  1.6  rillig 	ull = i - u;
     35  1.6  rillig 	/* expect+1: warning: suggest cast from 'unsigned int' to 'unsigned long long' on op * to avoid overflow [324] */
     36  1.6  rillig 	ull = u * i;
     37  1.6  rillig 	/* expect+1: warning: suggest cast from 'int' to 'long long' on op << to avoid overflow [324] */
     38  1.6  rillig 	ll = i << c;
     39  1.2  rillig 
     40  1.2  rillig 	/*
     41  1.2  rillig 	 * The operators SHR, DIV and MOD cannot produce an overflow,
     42  1.2  rillig 	 * therefore no warning is necessary for them.
     43  1.2  rillig 	 */
     44  1.4  rillig 	ll = i >> c;
     45  1.4  rillig 	ull = u / c;
     46  1.4  rillig 	ull = u % c;
     47  1.3  rillig 
     48  1.3  rillig 	/*
     49  1.3  rillig 	 * Assigning the result of an increment or decrement operator to a
     50  1.3  rillig 	 * differently-sized type is no unusual that there is no need to warn
     51  1.3  rillig 	 * about it.  It's also more unlikely that there is an actual loss
     52  1.3  rillig 	 * since this only happens for a single value of the old type, unlike
     53  1.4  rillig 	 * "ull = u * u", which has many more possibilities for overflowing.
     54  1.3  rillig 	 */
     55  1.4  rillig 	ull = u++;
     56  1.4  rillig 	ull = ++u;
     57  1.4  rillig 	ull = u--;
     58  1.4  rillig 	ull = --u;
     59  1.2  rillig }
     60