[EarlyCSE] Add option to use MemorySSA for function simplification run of EarlyCSE...

Summary:
Use MemorySSA for memory dependency checking in the EarlyCSE pass at the
start of the function simplification portion of the pipeline.  We rely
on the fact that GVNHoist runs just after this pass of EarlyCSE to
amortize the MemorySSA construction cost since GVNHoist uses MemorySSA
and EarlyCSE preserves it.

This is turned off by default.  A follow-up change will turn it on to
allow for easier reversion in case it breaks something.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@305146 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Passes/PassBuilder.cpp b/lib/Passes/PassBuilder.cpp
index 1f638e7683078cc53726b8db60cf80726cca71cb..afd66f55720a5fa1bb4811a8bc4736041f1fdd91 100644 (file)
--- a/lib/Passes/PassBuilder.cpp
+++ b/lib/Passes/PassBuilder.cpp
@@ -160,6 +160,10 @@ static cl::opt<bool>
               cl::Hidden, cl::ZeroOrMore,
               cl::desc("Run NewGVN instead of GVN"));
 
+static cl::opt<bool> EnableEarlyCSEMemSSA(
+    "enable-npm-earlycse-memssa", cl::init(false), cl::Hidden,
+    cl::desc("Enable the EarlyCSE w/ MemorySSA pass for the new PM (default = off)"));
+
 static cl::opt<bool> EnableGVNHoist(
     "enable-npm-gvn-hoist", cl::init(false), cl::Hidden,
     cl::desc("Enable the GVN hoisting pass for the new PM (default = off)"));
@@ -312,7 +316,7 @@ PassBuilder::buildFunctionSimplificationPipeline(OptimizationLevel Level,
   FPM.addPass(SROA());
 
   // Catch trivial redundancies
-  FPM.addPass(EarlyCSEPass());
+  FPM.addPass(EarlyCSEPass(EnableEarlyCSEMemSSA));
 
   // Hoisting of scalars and load expressions.
   if (EnableGVNHoist)

diff --git a/lib/Transforms/IPO/PassManagerBuilder.cpp b/lib/Transforms/IPO/PassManagerBuilder.cpp
index 16fba32e98056ee20a325a4ae8666ddc22c56a89..4bc64ab698ff9b4e44dfb9a4b034d215e9d30508 100644 (file)
--- a/lib/Transforms/IPO/PassManagerBuilder.cpp
+++ b/lib/Transforms/IPO/PassManagerBuilder.cpp
@@ -141,6 +141,10 @@ static cl::opt<int> PreInlineThreshold(
     cl::desc("Control the amount of inlining in pre-instrumentation inliner "
              "(default = 75)"));
 
+static cl::opt<bool> EnableEarlyCSEMemSSA(
+    "enable-earlycse-memssa", cl::init(false), cl::Hidden,
+    cl::desc("Enable the EarlyCSE w/ MemorySSA pass (default = off)"));
+
 static cl::opt<bool> EnableGVNHoist(
     "enable-gvn-hoist", cl::init(false), cl::Hidden,
     cl::desc("Enable the GVN hoisting pass (default = off)"));
@@ -308,7 +312,7 @@ void PassManagerBuilder::addFunctionSimplificationPasses(
   // Start of function pass.
   // Break up aggregate allocas, using SSAUpdater.
   MPM.add(createSROAPass());
-  MPM.add(createEarlyCSEPass());              // Catch trivial redundancies
+  MPM.add(createEarlyCSEPass(EnableEarlyCSEMemSSA)); // Catch trivial redundancies
   if (EnableGVNHoist)
     MPM.add(createGVNHoistPass());
   if (EnableGVNSink) {