Substitutions in Graal

[Doug Simon]

On May 29, 2014, at 5:48 PM, Juan Jose Fumero <juan.fumero at ed.ac.uk> wrote:

> Hi Doug, 
>    In our OpenCL backend we created the OCLMath class with basically returns a float and double of Java maths operations. So, instead of using
> Math.log for example, the user writes OCLMath.log . 
> 
> But, in order to be this implementation legal from Java code, OCLMath is actually a wrapper that calls to Math.* methods. 
> 
> 
> public class OCLMath {
> 
>     public static float fabs(float a) {
>         return Math.abs(a);
>     }
>   ....
> 
> } 
> 
> 
> And then our OCLMathSubstitution 
> 
> @ClassSubstitution(com.edinburgh.opencl.math.OCLMath.class)
> public class OCLMathSubstitutions {
> 
>     @MethodSubstitution
>     public static float fabs(float x) {
>         return OCLMathIntrinsicNode.compute(x, Operation.FABS);
>     }
> ... 
> 
> 
> This approach is quite similar to HSAIL. 
> 
> 
> My register substitution inherits from ReplacementImpl class. 
> 
> public class OCLHotSpotReplacementsImpl extends ReplacementsImpl {
> 
>     public OCLHotSpotReplacementsImpl(Providers providers, SnippetReflectionProvider snippetReflection, Assumptions assumptions, TargetDescription target) {
>         super(providers, snippetReflection, assumptions, target);
>         registerSubstitutions(Math.class, OCLMathSubstitutions.class);

This above line should be:

    registerSubstitutions(OCLMath.class, OCLMathSubstitutions.class);

You want to register substitutions for OCLMath, not Math. If you run with -esa enabled, this assert on ReplacementsImpl.java:322 should fire:

        assert getOriginalInternalName(substitutionClass).equals(internalName) : getOriginalInternalName(substitutionClass) + " != " + (internalName);

-Doug

> On Thu, 2014-05-29 at 15:34 +0200, Doug Simon wrote:
>> Hi Juan,
>> 
>> What’s in OCLMathSubstitutions? Does it override substitutions provide by MathSubstitutionsX86?
>> 
>> And where is your call to registerSubstitutions(Math.class, OCLMathSubstitutions.class)?
>> 
>> In standard Graal, I don’t think we have a multiple substitutions for a single method so have never thought about which substitution takes precedence in the case of conflicts.
>> 
>> -Doug
>> 
>> On May 29, 2014, at 11:52 AM, Juan Jose Fumero <
>> juan.fumero at ed.ac.uk
>> > wrote:
>> 
>> 
>> > Hi,
>> > 
>> > after this merge [1]  with my fork, I had to change the replacements
>> > from this
>> > 
>> > registerSubstitutions(OCLMathSubstitutions.class);
>> > 
>> > for this one:
>> > 
>> > registerSubstitutions(Math.class, OCLMathSubstitutions.class);
>> > 
>> > But, when I apply the replacements and inlining,  the MatIntrinsics is
>> > still my graph. 
>> > 
>> > ...
>> > 114|MathIntrinsic
>> > 119|Const(0.31938154)
>> > 120|Const(-0.35656378)
>> > 121|Const(1.7814779)
>> > ...
>> > 
>> > I want to substitute MathIntrinsic for OCLMathIntrinsic. 
>> > With my previous version (merge with Graal 839cb35354e8 [2] ) it works. 
>> > 
>> > Any idea?
>> > 
>> > Many thanks
>> > 
>> > 
>> > [1] http://hg.openjdk.java.net/graal/graal/rev/5c73b162eec2
>> > [2] http://hg.openjdk.java.net/graal/graal/rev/839cb35354e8
>> > 
>> > The University of Edinburgh is a charitable body, registered in
>> > Scotland, with registration number SC005336.
>> 
>> 
>> 
>> 
> 
> The University of Edinburgh is a charitable body, registered in
> Scotland, with registration number SC005336.