It's about 1% speedup for Stockfish.
Result of 100 runs
==================
base (...fish_clang12) =
1946851 +/- 3717
test (./stockfish ) =
1967276 +/- 3408
diff = +20425 +/- 2438
speedup = +0.0105
P(speedup > 0) = 1.0000
Thanks to David Major for making me aware of this part
of LLVM development.
closes https://github.com/official-stockfish/Stockfish/pull/3346
No functional change
CXXFLAGS += -mdynamic-no-pic
endif
endif
+
+ ifeq ($(comp),clang)
+ CXXFLAGS += -fexperimental-new-pass-manager
+ endif
endif
### 3.4 Bits