xref: /llvm-project/compiler-rt/test/nsan/fcmp.cpp (revision 86c640323286f4d692a634373c71536795cd7290)
1*86c64032Sc8ef // RUN: %clangxx_nsan -O2 -g %s -o %t
2*86c64032Sc8ef // RUN: env NSAN_OPTIONS=check_cmp=true,halt_on_error=0 %run %t 2>&1 | FileCheck %s -check-prefix=CMP_ENABLE
3*86c64032Sc8ef // RUN: env NSAN_OPTIONS=check_cmp=false,halt_on_error=0 %run %t 2>&1 | FileCheck %s -check-prefix=CMP_DISABLE
4*86c64032Sc8ef 
5*86c64032Sc8ef #include <cmath>
6*86c64032Sc8ef #include <cstdio>
7*86c64032Sc8ef 
8*86c64032Sc8ef // 0.6/0.2 is slightly below 3, so the comparison will fail after a certain
9*86c64032Sc8ef // threshold that depends on the precision of the computation.
10*86c64032Sc8ef __attribute__((noinline))  // To check call stack reporting.
11*86c64032Sc8ef bool DoCmp(double a, double b, double c, double threshold) {
12*86c64032Sc8ef   return c - a / b < threshold;
13*86c64032Sc8ef   // CMP_ENABLE: WARNING: NumericalStabilitySanitizer: floating-point comparison results depend on precision
14*86c64032Sc8ef   // CMP_ENABLE: double    {{ *}}precision dec (native): {{.*}}<{{.*}}
15*86c64032Sc8ef   // CMP_ENABLE: __float128{{ *}}precision dec (shadow): {{.*}}<{{.*}}
16*86c64032Sc8ef   // CMP_ENABLE: {{#0 .*in DoCmp}}
17*86c64032Sc8ef }
18*86c64032Sc8ef 
19*86c64032Sc8ef int main() {
20*86c64032Sc8ef   double threshold = 1.0;
21*86c64032Sc8ef   for (int i = 0; i < 60; ++i) {
22*86c64032Sc8ef     threshold /= 2;
23*86c64032Sc8ef     // CMP_DISABLE: value at threshold {{.*}}
24*86c64032Sc8ef     printf("value at threshold %.20f: %i\n", threshold,
25*86c64032Sc8ef            DoCmp(0.6, 0.2, 3.0, threshold));
26*86c64032Sc8ef   }
27*86c64032Sc8ef   return 0;
28*86c64032Sc8ef }
29