blob: 25739b778ce247f320416f37650cd5310591aac6 [file] [log] [blame]
 /* * This test stresses masking and sign-extension after int operations * that cause overflow, producing bogus high-order bits. * The basic overflow situation (x * x + y * y, for x = y = 1 << 21) * actually happens in Olden-perimeter, in the function CheckOutside. * * Several things have to happen correctly: * -- correct constant folding if it is done at compile-time * -- correct sign-extensions during native code generation for -, * and /. * -- correct handling of high bits during native code generation for * a sequence of operations involving -, * and /. */ #include void compareOvf(int x, int y) { int sum = x * x + y * y; if (sum < (1 << 22)) printf("compare after overflow is TRUE\n"); else printf("compare after overflow is FALSE\n"); } void divideOvf(int x, int y) { int sum = x * x + y * y; int rem = (1 << 31) / sum; printf("divide after overflow = %d (0x%x)\n", rem, rem); } void divideNeg(int x, int y) { int sum = x * x - y * y; int rem = sum / (1 << 18); printf("divide negative value by power-of-2 = %d (0x%x)\n", rem, rem); } void subtractOvf(int x, int y) { int sum = x * x + y * y; int rem = (1u << 31) - sum; printf("subtract after overflow = %d (0x%x)\n", rem, rem); } int main() { int b21 = 1 << 21; compareOvf(b21, b21); divideOvf(b21 + 1, b21 + 2); divideNeg(b21 + 1, b21 + 2); /* arg1 must be < arg2 */ subtractOvf(b21 + 1, b21 + 2); return 0; }