RFR: 8265711: C1: Canonicalize Class.getModifier intrinsic method

[Tobias Hartmann]

On Thu, 22 Apr 2021 07:02:29 GMT, Yi Yang <yyang at openjdk.org> wrote:

> It's relatively a common case to get modifiers from a constant Class instance, i.e. ThirdPartyClass.class.getModifiers(). Currently, C1 Canonicalizer missed the opportunity of replacing Class.getModifiers intrinsic calls with compile-time constants.

Changes requested by thartmann (Reviewer).

src/hotspot/share/c1/c1_Canonicalizer.cpp line 551:

> 549:     break;
> 550:   }
> 551:   case vmIntrinsics::_getModifiers           : {

Although old code below has this weird style, please change this to `_getModifiers: {`

src/hotspot/share/c1/c1_Canonicalizer.cpp line 558:

> 556:     if (c != NULL && !c->value()->is_null_object()) {
> 557:       ciType* t = c->value()->java_mirror_type();
> 558:       if (t->is_klass()) {

Shouldn't `t->is_primitive_type()` be handled as well?

test/hotspot/jtreg/compiler/c1/CanonicalizeGetModifiers.java line 94:

> 92: 
> 93:     public static void main(String... args) {
> 94:         for (int i = 0; i < 1_0000; i++) {

The thousand separator is at the wrong place, should be `10_000`.

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PR: https://git.openjdk.java.net/jdk/pull/3616