[CFLAA] Split into Anders+Steens analysis.

StratifiedSets (as implemented) is very fast, but its accuracy is also
limited. If we take a more aggressive andersens-like approach, we can be
way more accurate, but we'll also end up being slower.

So, we've decided to split CFLAA into CFLSteensAA and CFLAndersAA.

Long-term, we want to end up in a place where CFLSteens is queried
first; if it can provide an answer, great (since queries are basically
map lookups). Otherwise, we'll fall back to CFLAnders, BasicAA, etc.

This patch splits everything out so we can try to do something like
that when we get a reasonable CFLAnders implementation.

Patch by Jia Chen.

Differential Revision: http://reviews.llvm.org/D21910

llvm-svn: 274589

1 files changed, 30 insertions, 6 deletions

diff --git a/llvm/lib/CodeGen/TargetPassConfig.cpp b/llvm/lib/CodeGen/TargetPassConfig.cpp
index 1b30cc8ee54..332a8b7e323 100644
--- a/llvm/lib/CodeGen/TargetPassConfig.cpp
+++ b/llvm/lib/CodeGen/TargetPassConfig.cpp
@@ -15,7 +15,8 @@
 #include "llvm/CodeGen/TargetPassConfig.h"
 
 #include "llvm/Analysis/BasicAliasAnalysis.h"
-#include "llvm/Analysis/CFLAliasAnalysis.h"
+#include "llvm/Analysis/CFLAndersAliasAnalysis.h"
+#include "llvm/Analysis/CFLSteensAliasAnalysis.h"
 #include "llvm/Analysis/CallGraphSCCPass.h"
 #include "llvm/Analysis/Passes.h"
 #include "llvm/Analysis/ScopedNoAliasAA.h"
@@ -110,9 +111,19 @@ cl::opt<bool> MISchedPostRA("misched-postra", cl::Hidden,
 static cl::opt<bool> EarlyLiveIntervals("early-live-intervals", cl::Hidden,
     cl::desc("Run live interval analysis earlier in the pipeline"));
 
-static cl::opt<bool> UseCFLAA("use-cfl-aa-in-codegen",
-  cl::init(false), cl::Hidden,
-  cl::desc("Enable the new, experimental CFL alias analysis in CodeGen"));
+// Experimental option to use CFL-AA in codegen
+enum class CFLAAType { None, Steensgaard, Andersen, Both };
+static cl::opt<CFLAAType> UseCFLAA(
+    "use-cfl-aa-in-codegen", cl::init(CFLAAType::None), cl::Hidden,
+    cl::desc("Enable the new, experimental CFL alias analysis in CodeGen"),
+    cl::values(clEnumValN(CFLAAType::None, "none", "Disable CFL-AA"),
+               clEnumValN(CFLAAType::Steensgaard, "steens",
+                          "Enable unification-based CFL-AA"),
+               clEnumValN(CFLAAType::Andersen, "anders",
+                          "Enable inclusion-based CFL-AA"),
+               clEnumValN(CFLAAType::Both, "both", 
+                          "Enable both variants of CFL-AA"),
+               clEnumValEnd));
 
 cl::opt<bool> UseIPRA("enable-ipra", cl::init(false), cl::Hidden,
                       cl::desc("Enable interprocedural register allocation "
@@ -414,12 +425,25 @@ void TargetPassConfig::addVerifyPass(const std::string &Banner) {
 /// Add common target configurable passes that perform LLVM IR to IR transforms
 /// following machine independent optimization.
 void TargetPassConfig::addIRPasses() {
+  switch (UseCFLAA) {
+  case CFLAAType::Steensgaard:
+    addPass(createCFLSteensAAWrapperPass());
+    break;
+  case CFLAAType::Andersen:
+    addPass(createCFLAndersAAWrapperPass());
+    break;
+  case CFLAAType::Both:
+    addPass(createCFLAndersAAWrapperPass());
+    addPass(createCFLSteensAAWrapperPass());
+    break;
+  default:
+    break;
+  }
+
   // Basic AliasAnalysis support.
   // Add TypeBasedAliasAnalysis before BasicAliasAnalysis so that
   // BasicAliasAnalysis wins if they disagree. This is intended to help
   // support "obvious" type-punning idioms.
-  if (UseCFLAA)
-    addPass(createCFLAAWrapperPass());
   addPass(createTypeBasedAAWrapperPass());
   addPass(createScopedNoAliasAAWrapperPass());
   addPass(createBasicAAWrapperPass());