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msg_267.c revision 1.11 
      1 /*	$NetBSD: msg_267.c,v 1.11 2025/09/14 12:05:05 rillig Exp $	*/
      2 # 3 "msg_267.c"
      3 
      4 // Test for message: shift amount %u equals bit-size of '%s' [267]
      5 
      6 /* lint1-extra-flags: -X 351 */
      7 
      8 int
      9 shr32(unsigned int x)
     10 {
     11 	/* expect+1: warning: shift amount 32 equals bit-size of 'unsigned int' [267] */
     12 	return x >> 32;
     13 }
     14 
     15 int
     16 shl32(unsigned int x)
     17 {
     18 	/* expect+1: warning: shift amount 32 equals bit-size of 'unsigned int' [267] */
     19 	return x << 32;
     20 }
     21 
     22 /*
     23  * https://gcc.gnu.org/onlinedocs/gccint/Machine-Modes.html
     24  */
     25 unsigned
     26 function(unsigned __attribute__((mode(TI))) arg)
     27 {
     28 	return (arg >> 32) & 3;
     29 }
     30 
     31 unsigned
     32 shift_bit_field(void)
     33 {
     34 	struct {
     35 		unsigned bit_field:18;
     36 	} s = { 12345 };
     37 
     38 	/*
     39 	 * A warning may be useful here for '>>' with a shift amount >= 18.
     40 	 *
     41 	 * For '<<' and bit-size <= 31, a warning only makes sense for shift
     42 	 * amounts >= 31, as it is legitimate to rely on the default integer
     43 	 * promotions of the left-hand operand. The default integer promotion
     44 	 * turns the type into 'int', not 'unsigned int', therefore the 31.
     45 	 * Using the same warning text would be confusing though.
     46 	 *
     47 	 * For '<<' and bit-size == 32, the standard case applies.
     48 	 *
     49 	 * As of 2022-08-19, Clang-tidy doesn't warn about any of these.
     50 	 */
     51 	return
     52 	    (s.bit_field >> 17) &
     53 	    (s.bit_field >> 18) &
     54 	    (s.bit_field >> 19) &
     55 	    (s.bit_field >> 31) &
     56 	    // When promoting 'unsigned int:18', the target type is 'int', as
     57 	    // it can represent all possible values; this is a bit misleading
     58 	    // as its sign bit is always 0.
     59 	    /* expect+1: warning: shift amount 32 equals bit-size of 'int promoted from unsigned int:18' [267] */
     60 	    (s.bit_field >> 32) &
     61 	    // When promoting 'unsigned int:18', the target type is 'int', as
     62 	    // it can represent all possible values; this is a bit misleading
     63 	    // as its sign bit is always 0.
     64 	    /* expect+1: warning: shift amount 33 is greater than bit-size 32 of 'int promoted from unsigned int:18' [122] */
     65 	    (s.bit_field >> 33) &
     66 	    (s.bit_field << 17) &
     67 	    (s.bit_field << 18) &
     68 	    (s.bit_field << 19) &
     69 	    (s.bit_field << 31) &
     70 	    // When promoting 'unsigned int:18', the target type is 'int', as
     71 	    // it can represent all possible values; this is a bit misleading
     72 	    // as its sign bit is always 0.
     73 	    /* expect+1: warning: shift amount 32 equals bit-size of 'int promoted from unsigned int:18' [267] */
     74 	    (s.bit_field << 32) &
     75 	    // When promoting 'unsigned int:18', the target type is 'int', as
     76 	    // it can represent all possible values; this is a bit misleading
     77 	    // as its sign bit is always 0.
     78 	    /* expect+1: warning: shift amount 33 is greater than bit-size 32 of 'int promoted from unsigned int:18' [122] */
     79 	    (s.bit_field << 33) &
     80 	    15;
     81 }
     82