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Unified Diff: src/interpreter/mkpeephole.cc

Issue 2547043002: [Interpreter] Optimize equality check with null/undefined with a check on the map. (Closed)
Patch Set: Fixed a bug in reducing JSIsUndetectable. Created 4 years ago
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Index: src/interpreter/mkpeephole.cc
diff --git a/src/interpreter/mkpeephole.cc b/src/interpreter/mkpeephole.cc
index 62d3a77e02c7faf513f1d8ff020217b6fd4785dd..81f35f670112ccf002c5c971cdbc14bb590a9dbc 100644
--- a/src/interpreter/mkpeephole.cc
+++ b/src/interpreter/mkpeephole.cc
@@ -192,6 +192,19 @@ PeepholeActionAndData PeepholeActionTableWriter::LookupActionAndData(
}
}
+ // Fuse LdaNull/LdaUndefined followed by a equality comparison with test
+ // undetectable. Testing undetectable is a simple check on the map which is
+ // more efficient than the full comparison operation.
+ // Note: StrictEquals cannot use this, they need to compare it with the
+ // Null/undefined map.
+ if (last == Bytecode::kLdaNull || last == Bytecode::kLdaUndefined) {
+ if (current == Bytecode::kTestEqual) {
+ return {PeepholeAction::
+ kTransformEqualityWithNullOrUndefinedToTestUndetectableAction,
+ Bytecode::kTestUndetectable};
rmcilroy 2016/12/05 10:57:19 Could we also fuse NotEquals too (with another byt
mythria 2016/12/05 14:53:11 Full-codegen does not do this, so I wasn't sure we
+ }
+ }
+
// If there is no last bytecode to optimize against, store the incoming
// bytecode or for jumps emit incoming bytecode immediately.
if (last == Bytecode::kIllegal) {

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