[flang-commits] [PATCH] D105970: [flang] Add POSIX implementation for SYSTEM_CLOCK

[Peter Klausler via Phabricator via flang-commits]

klausler added inline comments.


================
Comment at: flang/runtime/time-intrinsic.cpp:136
+  // Wrap around to avoid overflows.
+  count_t max_secs = std::numeric_limits<count_t>::max() / NSECS_PER_SEC;
+  count_t wrapped_secs = tspec.tv_sec % max_secs;
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rovka wrote:
> klausler wrote:
> > Can be constexpr.
> > 
> > Since `count_t` is a 64-bit signed integer, max_secs is going to be ca. 8e9,  or roughly 300 years.  That might make it hard to test your overflow cases.
> Well, the POSIX epoch ought to be set to 1970, and most code survives longer than people expect it to, so I'm sure it will be relevant :P
> Anyway, on a serious note, are you saying we should skip the wrapping altogether and just return tv_nsec + tv_sec * NSECS_PER_SEC?
No, I was pointing out that the overflow path isn't tested.  Not a big deal.


Repository:
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  https://reviews.llvm.org/D105970/new/

https://reviews.llvm.org/D105970