RFR [8]: Fix x86_32 build

[Roman Kennke]

Am 18.07.2018 um 11:43 schrieb Aleksey Shipilev:
> sh/jdk8u build on x86_32 fails because there is no Atomic::load for intptr_t in jdk8:
> 
> diff -r 3b776ba499bb src/share/vm/gc_implementation/shenandoah/shenandoahPacer.cpp
> --- a/src/share/vm/gc_implementation/shenandoah/shenandoahPacer.cpp     Mon Jul 16 11:57:03 2018 -0400
> +++ b/src/share/vm/gc_implementation/shenandoah/shenandoahPacer.cpp     Wed Jul 18 11:43:11 2018 +0200
> @@ -210,11 +210,11 @@
>    intptr_t tax = MAX2<intptr_t>(1, (intptr_t)(words * OrderAccess::load_acquire(&_tax_rate)));
>    Atomic::add(tax, &_budget);
>  }
> 
>  intptr_t ShenandoahPacer::epoch() {
> -  return Atomic::load(&_epoch);
> +  return OrderAccess::load_acquire(&_epoch);
>  }
> 
>  void ShenandoahPacer::pace_for_alloc(size_t words) {
>    assert(ShenandoahPacing, "Only be here when pacing is enabled");
> 
> 
> Testing: x86_32 build, tier1_gc_shenandoah

Ok. Ordinary load doesn't do it? intptr_t on x86_32 is 32bit and atomic,
or is it not?

Roman