1 // RUN: %clangxx_nsan -O2 -g %s -o %t 2 // RUN: env NSAN_OPTIONS=check_cmp=true,halt_on_error=0 %run %t 2>&1 | FileCheck %s -check-prefix=CMP_ENABLE 3 // RUN: env NSAN_OPTIONS=check_cmp=false,halt_on_error=0 %run %t 2>&1 | FileCheck %s -check-prefix=CMP_DISABLE 4 5 #include <cmath> 6 #include <cstdio> 7 8 // 0.6/0.2 is slightly below 3, so the comparison will fail after a certain 9 // threshold that depends on the precision of the computation. 10 __attribute__((noinline)) // To check call stack reporting. 11 bool DoCmp(double a, double b, double c, double threshold) { 12 return c - a / b < threshold; 13 // CMP_ENABLE: WARNING: NumericalStabilitySanitizer: floating-point comparison results depend on precision 14 // CMP_ENABLE: double {{ *}}precision dec (native): {{.*}}<{{.*}} 15 // CMP_ENABLE: __float128{{ *}}precision dec (shadow): {{.*}}<{{.*}} 16 // CMP_ENABLE: {{#0 .*in DoCmp}} 17 } 18 19 int main() { 20 double threshold = 1.0; 21 for (int i = 0; i < 60; ++i) { 22 threshold /= 2; 23 // CMP_DISABLE: value at threshold {{.*}} 24 printf("value at threshold %.20f: %i\n", threshold, 25 DoCmp(0.6, 0.2, 3.0, threshold)); 26 } 27 return 0; 28 } 29