Enable Local CSE by default
Reduce the default number of iterations to 1
Put the optional code behind the -lcse-no-ssa flag, which is disabled by
default. This brings down the overhead of enabling this to about 2%.
BUG=
R=stichnot@chromium.org
Review URL: https://codereview.chromium.org/2185193002 .
diff --git a/src/IceClFlags.def b/src/IceClFlags.def
index 2af1ee4..0281e7d 100644
--- a/src/IceClFlags.def
+++ b/src/IceClFlags.def
@@ -140,9 +140,14 @@
"information to stdout at the end of program execution."), \
cl::init(false)) \
\
- X(EnableExperimental, bool, dev_opt_flag, "enable-experimental", \
- cl::desc("Enable Optimizations not yet part of O2"), \
- cl::init(false)) \
+ X(LocalCSE, Ice::LCSEOptions, dev_opt_flag, "lcse", \
+ cl::desc("Local common subexpression elimination"), \
+ cl::init(Ice::LCSE_EnabledSSA), \
+ cl::values( \
+ clEnumValN(Ice::LCSE_Disabled, "0", "disabled"), \
+ clEnumValN(Ice::LCSE_EnabledSSA, "enabled", "assume-ssa"), \
+ clEnumValN(Ice::LCSE_EnabledNoSSA, "no-ssa", "no-assume-ssa"), \
+ clEnumValEnd)) \
\
X(EnablePhiEdgeSplit, bool, dev_opt_flag, "phi-edge-split", \
cl::desc("Enable edge splitting for Phi lowering"), cl::init(true)) \
@@ -186,8 +191,8 @@
"building LLVM IR first"), \
cl::init(false)) \
\
- X(LocalCseMaxIterations, int, dev_opt_flag, "lcse-max-iters", \
- cl::desc("Number of times local-cse is run on a block"), cl::init(2)) \
+ X(LocalCseMaxIterations, uint32_t, dev_opt_flag, "lcse-max-iters", \
+ cl::desc("Number of times local-cse is run on a block"), cl::init(1)) \
\
X(LoopInvariantCodeMotion, bool, dev_opt_flag, "licm", \
cl::desc("Hoist loop invariant arithmetic operations"), cl::init(false)) \
