29 lines
1.1 KiB
C++
29 lines
1.1 KiB
C++
// RUN: %clangxx_nsan -O2 -g %s -o %t
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// RUN: env NSAN_OPTIONS=check_cmp=true,halt_on_error=0 %run %t 2>&1 | FileCheck %s -check-prefix=CMP_ENABLE
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// RUN: env NSAN_OPTIONS=check_cmp=false,halt_on_error=0 %run %t 2>&1 | FileCheck %s -check-prefix=CMP_DISABLE
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#include <cmath>
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#include <cstdio>
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// 0.6/0.2 is slightly below 3, so the comparison will fail after a certain
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// threshold that depends on the precision of the computation.
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__attribute__((noinline)) // To check call stack reporting.
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bool DoCmp(double a, double b, double c, double threshold) {
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return c - a / b < threshold;
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// CMP_ENABLE: WARNING: NumericalStabilitySanitizer: floating-point comparison results depend on precision
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// CMP_ENABLE: double {{ *}}precision dec (native): {{.*}}<{{.*}}
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// CMP_ENABLE: __float128{{ *}}precision dec (shadow): {{.*}}<{{.*}}
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// CMP_ENABLE: {{#0 .*in DoCmp}}
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}
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int main() {
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double threshold = 1.0;
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for (int i = 0; i < 60; ++i) {
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threshold /= 2;
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// CMP_DISABLE: value at threshold {{.*}}
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printf("value at threshold %.20f: %i\n", threshold,
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DoCmp(0.6, 0.2, 3.0, threshold));
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}
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return 0;
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}
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