From 4021fccf9fdb60906e5f16c98e72042240867495 Mon Sep 17 00:00:00 2001
From: Dan Gohman <gohman@apple.com>
Date: Mon, 18 Oct 2010 18:50:27 +0000
Subject: [PATCH] Add TypeBasedAliasAnalysis to the standard pass lists. Note
 that it is currently inert by default.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@116732 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/llvm/Support/StandardPasses.h | 14 +++++++++++---
 lib/CodeGen/LLVMTargetMachine.cpp     |  4 ++--
 2 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/include/llvm/Support/StandardPasses.h b/include/llvm/Support/StandardPasses.h
index deee00e686a..a608f2ceaba 100644
--- a/include/llvm/Support/StandardPasses.h
+++ b/include/llvm/Support/StandardPasses.h
@@ -69,10 +69,18 @@ namespace llvm {
 
   // Implementations
 
+  static inline void createStandardAliasAnalysisPasses(PassManagerBase *PM) {
+    // Add TypeBasedAliasAnalysis before BasicAliasAnalysis so that
+    // BasicAliasAnalysis wins if they disagree. This is intended to help
+    // support "obvious" type-punning idioms.
+    PM->add(createTypeBasedAliasAnalysisPass());
+    PM->add(createBasicAliasAnalysisPass());
+  }
+
   static inline void createStandardFunctionPasses(PassManagerBase *PM,
                                                   unsigned OptimizationLevel) {
     if (OptimizationLevel > 0) {
-      PM->add(createBasicAliasAnalysisPass());
+      createStandardAliasAnalysisPasses(PM);
       PM->add(createCFGSimplificationPass());
       if (OptimizationLevel == 1)
         PM->add(createPromoteMemoryToRegisterPass());
@@ -92,7 +100,7 @@ namespace llvm {
                                                 bool SimplifyLibCalls,
                                                 bool HaveExceptions,
                                                 Pass *InliningPass) {
-    PM->add(createBasicAliasAnalysisPass());
+    createStandardAliasAnalysisPasses(PM);
 
     if (OptimizationLevel == 0) {
       if (InliningPass)
@@ -181,7 +189,7 @@ namespace llvm {
                                              bool RunInliner,
                                              bool VerifyEach) {
     // Provide AliasAnalysis services for optimizations.
-    PM->add(createBasicAliasAnalysisPass());
+    createStandardAliasAnalysisPasses(PM);
 
     // Now that composite has been compiled, scan through the module, looking
     // for a main function.  If main is defined, mark all other functions
diff --git a/lib/CodeGen/LLVMTargetMachine.cpp b/lib/CodeGen/LLVMTargetMachine.cpp
index a3b605238ab..60aa1e5c984 100644
--- a/lib/CodeGen/LLVMTargetMachine.cpp
+++ b/lib/CodeGen/LLVMTargetMachine.cpp
@@ -14,7 +14,6 @@
 #include "llvm/Target/TargetMachine.h"
 #include "llvm/PassManager.h"
 #include "llvm/Analysis/Verifier.h"
-#include "llvm/Analysis/Passes.h"
 #include "llvm/Assembly/PrintModulePass.h"
 #include "llvm/CodeGen/AsmPrinter.h"
 #include "llvm/CodeGen/MachineFunctionAnalysis.h"
@@ -31,6 +30,7 @@
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/FormattedStream.h"
+#include "llvm/Support/StandardPasses.h"
 using namespace llvm;
 
 namespace llvm {
@@ -256,7 +256,7 @@ bool LLVMTargetMachine::addCommonCodeGenPasses(PassManagerBase &PM,
   // Standard LLVM-Level Passes.
 
   // Basic AliasAnalysis support.
-  PM.add(createBasicAliasAnalysisPass());
+  createStandardAliasAnalysisPasses(&PM);
 
   // Before running any passes, run the verifier to determine if the input
   // coming from the front-end and/or optimizer is valid.