clang/test/Sema/shift.c

   1 // RUN: %clang_cc1 -Wall -Wno-unused-but-set-variable -Wshift-sign-overflow -ffreestanding -fsyntax-only -verify %s
   2
   3 #include <limits.h>
   4
   5 #define WORD_BIT (sizeof(int) * CHAR_BIT)
   6
   7 enum {
   8   X = 1 << 0,
   9   Y = 1 << 1,
  10   Z = 1 << 2
  11 };
  12
  13 void test(void) {
  14   char c;
  15
  16   c = 0 << 0;
  17   c = 0 << 1;
  18   c = 1 << 0;
  19   c = 1 << -0;
  20   c = 1 >> -0;
  21   c = 1 << -1; // expected-warning {{shift count is negative}}
  22   c = 1 >> -1; // expected-warning {{shift count is negative}}
  23   c = 1 << (unsigned)-1; // expected-warning {{shift count >= width of type}}
  24                          // expected-warning@-1 {{implicit conversion}}
  25   c = 1 >> (unsigned)-1; // expected-warning {{shift count >= width of type}}
  26   c = 1 << c;
  27   c <<= 0;
  28   c >>= 0;
  29   c <<= 1;
  30   c >>= 1;
  31   c <<= -1; // expected-warning {{shift count is negative}}
  32   c >>= -1; // expected-warning {{shift count is negative}}
  33   c <<= 999999; // expected-warning {{shift count >= width of type}}
  34   c >>= 999999; // expected-warning {{shift count >= width of type}}
  35   c <<= CHAR_BIT; // expected-warning {{shift count >= width of type}}
  36   c >>= CHAR_BIT; // expected-warning {{shift count >= width of type}}
  37   c <<= CHAR_BIT+1; // expected-warning {{shift count >= width of type}}
  38   c >>= CHAR_BIT+1; // expected-warning {{shift count >= width of type}}
  39   (void)((long)c << CHAR_BIT);
  40
  41   int i;
  42   i = 1 << (WORD_BIT - 2);
  43   i = 2 << (WORD_BIT - 1); // expected-warning {{bits to represent, but 'int' only has}}
  44   i = 1 << (WORD_BIT - 1); // expected-warning {{sets the sign bit of the shift expression}}
  45   i = -1 << (WORD_BIT - 1); // expected-warning {{shifting a negative signed value is undefined}}
  46   i = -1 << 0; // expected-warning {{shifting a negative signed value is undefined}}
  47   i = 0 << (WORD_BIT - 1);
  48   i = (char)1 << (WORD_BIT - 2);
  49
  50   unsigned u;
  51   u = 1U << (WORD_BIT - 1);
  52   u = 5U << (WORD_BIT - 1);
  53
  54   long long int lli;
  55   lli = INT_MIN << 2; // expected-warning {{shifting a negative signed value is undefined}}
  56   lli = 1LL << (sizeof(long long) * CHAR_BIT - 2);
  57 }
  58
  59 #define a 0
  60 #define ashift 8
  61 enum { b = (a << ashift) };
  62
  63 // Don't warn for negative shifts in code that is unreachable.
  64 void test_pr5544(void) {
  65   (void) (((1) > 63 && (1) < 128 ? (((unsigned long long) 1)<<((1)-64)) : (unsigned long long) 0)); // no-warning
  66 }
  67
  68 void test_shift_too_much(char x) {
  69   if (0)
  70     (void) (x >> 80); // no-warning
  71   (void) (x >> 80); // expected-warning {{shift count >= width of type}}
  72 }
  73
  74 typedef unsigned vec16 __attribute__((vector_size(16)));
  75 typedef unsigned vec8 __attribute__((vector_size(8)));
  76
  77 void vect_shift_1(vec16 *x) { *x = *x << 4; }
  78
  79 void vect_shift_2(vec16 *x, vec16 y) { *x = *x << y; }
  80
  81 void vect_shift_3(vec16 *x, vec8 y) {
  82   *x = *x << y; // expected-error {{vector operands do not have the same number of elements}}
  83 }