[PATCH] D64746: Add constrained intrinsics for lrint and lround

[Cameron McInally via Phabricator via llvm-commits]

cameron.mcinally added inline comments.


================
Comment at: docs/LangRef.rst:15724
+mode is determined by the runtime floating-point environment.  The rounding
+mode argument is only intended as information to the compiler.
+
----------------
cameron.mcinally wrote:
> kpn wrote:
> > andrew.w.kaylor wrote:
> > > We should describe what is returned if the value is too large to be represented as a long. The llvm.lrint doesn't do that either, but it should too.
> > What do we want this to be? My draft copy of C99 says the return value is "unspecified". What does that translate to in LLVM-land? Is this listed in IEEE 754?
> That should throw an Invalid exception. And I think we agreed in your other Diff that it should return a poison value.
```
7.2 Invalid operation 

<...snip...>

For operations producing no result in floating-point format, the operations that signal the invalid operation exception are:

i) conversion of a floating-point number to an integer format, when the source is NaN, infinity, or a value that would convert to an integer outside the range of the result format under the applicable rounding attribute
```


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  https://reviews.llvm.org/D64746/new/

https://reviews.llvm.org/D64746