RFR: 8255672: Replace PhaseTransform::eqv by pointer equality check

[Christian Hagedorn]

On Mon, 2 Nov 2020 09:29:40 GMT, Tobias Hartmann <thartmann at openjdk.org> wrote:

> `PhaseTransform::eqv(n1, n2)` can be replaced by `n1 == n2`. Code in adlc also refers to it but already uses `==` instead.
> 
> Thanks,
> Tobias

Looks good to me!

src/hotspot/share/opto/subnode.cpp line 458:

> 456:     // Convert "x - (x+y)" into "-y"
> 457:     return new SubFNode(phase->makecon(TypeF::ZERO),in(2)->in(2));
> 458:   }

Missing space before `in(2)->in(2)`.

src/hotspot/share/opto/movenode.cpp line 129:

> 127:   if (phase->type(in(Condition)) == TypeInt::ZERO) {
> 128:     return in(IfFalse); // Always pick left(false) input
> 129:   }

Could be merged with the `if` above but might be clearer if left as it is now.

src/hotspot/share/opto/divnode.cpp line 1174:

> 1172:   if (in(1) == in(2)) {
> 1173:     return TypeLong::ZERO;
> 1174:   }

Could be merged with the `if` above.

src/hotspot/share/opto/divnode.cpp line 999:

> 997:   if (in(1) == in(2)) {
> 998:     return TypeInt::ZERO;
> 999:   }

Could be merged with the `if` above.

src/hotspot/share/opto/callnode.cpp line 1232:

> 1230:   if (in(0) == this) {
> 1231:     return Type::TOP; // Dead infinite loop
> 1232:   }

Could be merged with the `if` above but might be clearer if left as it is now.

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Marked as reviewed by chagedorn (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/999