[PATCH] 8217561 : X86: Add floating-point Math.min/max intrinsics

[B. Blaser]

Hi Jatin,

On Mon, 4 Feb 2019 at 13:53, Bhateja, Jatin <jatin.bhateja at intel.com> wrote:
>
> Hi Blaser,
>
> Please see response embedded in following mail.
>
> Best Regards,
> Jatin
>
> > -----Original Message-----
> > From: B. Blaser [mailto:bsrbnd at gmail.com]
> > Sent: Monday, February 4, 2019 5:13 PM
> >
> > Yes, of course, but I meant:
> >
> > http://cr.openjdk.java.net/~sviswanathan/Jatin/8217561/webrev.01/test/ho
> > tspot/jtreg/compiler/intrinsics/math/TestFpMinMaxIntrinsics.java.html
> >
> > I believe '-XX:CompileOnly=java/lang/Math' induce the compilation of
> > 'Math.max()' but not its intrinsification which occurs when the call is inlined,
> > see:
> >
> > http://hg.openjdk.java.net/jdk/jdk/rev/f15af1e2c683#l9.29
> >
>
> I can see that if a method is a candidate for intrinsification (which is decided during initialization as we create explicit vmSymbols for them) then during initial graph creation
> itself a specialized node is created for the call site (refer to processing of invoke* bytecodes done in Parse::do_call()). Thus intrinsification in this case will implicitly do the inlining.
>
> > http://hg.openjdk.java.net/jdk/jdk/file/d997c227e968/src/hotspot/share/op
> > to/library_call.cpp#l6611
> >
> > But this would be good if someone knowledgeable in this area could confirm
> > this?
> An experienced hand could comment more on this.

I think this is what Nils meant here:

http://mail.openjdk.java.net/pipermail/hotspot-compiler-dev/2019-January/032528.html

>>> Allow compilation of the methods in the test:
>>>
>>> "-XX:CompileCommand=compileonly,compiler.intrinsics.math.TestFpMinMaxIntrinsics*"
>>>
>>> And add a loop in the main method, so the test case is run multiple times

This is also what I observed in my example; you have to enable
compilation of the caller '-XX:CompileOnly=MinMax::test' and run it
multiple times to trigger inlining of the intrinsic (I'm not sure that
100 iterations as you added in 'TestFpMinMaxIntrinsics' are enough
though).

Bernard