feat: optimize instruction decoding primary switch into jump tables

cartesi · Oct 14, 2024 · 5ec2ff8 · 5ec2ff8
1 parent c5711c8
commit 5ec2ff8
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Showing 3 changed files with 338 additions and 308 deletions.
diff --git a/src/Makefile b/src/Makefile
@@ -210,9 +210,8 @@ ifneq (,$(filter gcc,$(CC)))
 # but we don't use -O3 because it enables some other flags that are not worth for the interpreter.
 INTERPRET_CXXFLAGS+=-fgcse-after-reload -fpredictive-commoning -fsplit-paths -ftree-partial-pre
 endif
-# Disable jump tables, because it degrades the instruction decoding performance in the interpret loop,
-# since it generates a memory indirection that has a high cost in opcode switches.
-INTERPRET_CXXFLAGS+=-fno-jump-tables
+# Enable large jump tables to improve performance of instruction decoding in interpret.cpp
+INTERPRET_CXXFLAGS+=-fjump-tables --param jump-table-max-growth-ratio-for-speed=4096
 endif
 
 # Link time optimizations