ART: Reduce the instructions generated by packed switch.
Implement Vladimir Marko's suggestion. The new compare/jump series
reduce the number of instructions from (2*n+1) to (1.5*n+3).
Generate normal compare/jump series when numEntries <= 3.
Generate optimal compare/jump series when numEntries <= threshold.
Generate jump tables otherwise.
Change-Id: I425547b6787057c7fa84e71f17c145b63b208633
diff --git a/compiler/optimizing/builder.h b/compiler/optimizing/builder.h
index c3979f3..ca71c32 100644
--- a/compiler/optimizing/builder.h
+++ b/compiler/optimizing/builder.h
@@ -90,8 +90,9 @@
static constexpr const char* kBuilderPassName = "builder";
- // The number of entries in a packed switch before we use a jump table.
- static constexpr uint16_t kSmallSwitchThreshold = 5;
+ // The number of entries in a packed switch before we use a jump table or specified
+ // compare/jump series.
+ static constexpr uint16_t kSmallSwitchThreshold = 3;
private:
// Analyzes the dex instruction and adds HInstruction to the graph