Displaying 2 results from an estimated 2 matches for "getsqrtcall".
2020 Sep 14
2
Invalid transformation in LibCallSimplifier::replacePowWithSqrt?
...with the code from the godbolt example.
Does the real motivating case have no uses of the pow() result value?
On Mon, Sep 14, 2020 at 1:03 PM Sanjay Patel <spatel at rotateright.com> wrote:
> Yes, I mean just bail out on the transform in
> LibCallSimplifier::replacePowWithSqrt() -> getSqrtCall(). If we can't prove
> the call behaves the same with errno, then give up.
> I'm not sure where the select / branching happens, but I don't see that
> happening in the initial transform (called from -instcombine)
>
> On Mon, Sep 14, 2020 at 12:58 PM Hubert Tong <
>...
2020 Sep 14
2
Invalid transformation in LibCallSimplifier::replacePowWithSqrt?
On Mon, Sep 14, 2020 at 12:45 PM Sanjay Patel <spatel at rotateright.com>
wrote:
> Yes, that looks like a bug. The transform is ok in general for negative
> numbers, but -Inf is a special-case for pow(), right?
> If so, we probably need an extra check of the input with
> "isKnownNeverInfinity()".
>
There is an extra check there already, but it uses