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[compiler-rt][ubsan] Refactor cast-overflow test (#129460)

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This PR cleans up cast-overflow.cpp, more specifically:
1. avoid using undefined value as an exit code (old case `9`)
2. narrowing conversions are allowed to produce `inf` and they are
well-defined. Remove dead code (old case `8`)
3. the same applies to the conversion int -> float16. Remove dead code
(old case `7`)

See also
https://clang.llvm.org/docs/UndefinedBehaviorSanitizer.html#:~:text=%2Dfsanitize%3Dfloat%2Dcast,to%20integer%20types.

Currently ubsan doesn't properly detect UB on float16 -> int casts, I
have a fix for that (will send as a separate PR).
This commit is contained in:
Alexander Shaposhnikov 2025-03-03 12:32:58 -08:00 committed by GitHub
parent 4ca8ea8c97
commit 39402cde61
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1 changed files with 7 additions and 16 deletions
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23
compiler-rt/test/ubsan/TestCases/Float/cast-overflow.cpp
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@ -7,9 +7,7 @@
// RUN: %run %t 4 2>&1 | FileCheck %s --check-prefix=CHECK-4
// RUN: %run %t 5 2>&1 | FileCheck %s --check-prefix=CHECK-5
// RUN: %run %t 6 2>&1 | FileCheck %s --check-prefix=CHECK-6
// FIXME: %run %t 7 2>&1 | FileCheck %s --check-prefix=CHECK-7
// FIXME: not %run %t 8 2>&1 | FileCheck %s --check-prefix=CHECK-8
// RUN: not %run %t 9 2>&1 | FileCheck %s --check-prefix=CHECK-9
// RUN: %run %t 7 2>&1 | FileCheck %s --check-prefix=CHECK-7
// Issue #41838
// XFAIL: sparc-target-arch && target={{.*solaris.*}}
@ -151,20 +149,13 @@ int main(int argc, char **argv) {
return 0;
#endif
}
// FIXME: The backend cannot lower __fp16 operations on x86 yet.
//case '7':
// (__fp16)65504; // ok
// // CHECK-7: runtime error: 65505 is outside the range of representable values of type '__fp16'
// return (__fp16)65505;
// Floating point -> floating point overflow.
case '8':
// CHECK-8: {{.*}}cast-overflow.cpp:[[@LINE+1]]:19: runtime error: 1e+39 is outside the range of representable values of type 'float'
return (float)1e39;
case '9':
case '7': {
volatile long double ld = 300.0;
// CHECK-9: {{.*}}cast-overflow.cpp:[[@LINE+1]]:14: runtime error: 300 is outside the range of representable values of type 'char'
// CHECK-7: {{.*}}cast-overflow.cpp:[[@LINE+1]]:14: runtime error: 300 is outside the range of representable values of type 'char'
char c = ld;
return c;
// `c` is allowed to contain UNDEF, thus we should not use
// its value as an exit code.
return 0;
}
}
}