29 lines · cpp
1// RUN: %clangxx_nsan -O2 -g %s -o %t2// RUN: env NSAN_OPTIONS=check_cmp=true,halt_on_error=0 %run %t 2>&1 | FileCheck %s -check-prefix=CMP_ENABLE3// RUN: env NSAN_OPTIONS=check_cmp=false,halt_on_error=0 %run %t 2>&1 | FileCheck %s -check-prefix=CMP_DISABLE4 5#include <cmath>6#include <cstdio>7 8// 0.6/0.2 is slightly below 3, so the comparison will fail after a certain9// threshold that depends on the precision of the computation.10__attribute__((noinline)) // To check call stack reporting.11bool 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 precision14 // CMP_ENABLE: double {{ *}}precision dec (native): {{.*}}<{{.*}}15 // CMP_ENABLE: __float128{{ *}}precision dec (shadow): {{.*}}<{{.*}}16 // CMP_ENABLE: {{#0 .*in DoCmp}}17}18 19int 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