Patch to make some xforms preserve each other. Patch contributed by

Domagoj Babic!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@28181 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Transforms/Utils/LowerAllocations.cpp

@@ -13,6 +13,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/Transforms/Scalar.h"
+#include "llvm/Transforms/Utils/UnifyFunctionExitNodes.h"
 #include "llvm/Module.h"
 #include "llvm/DerivedTypes.h"
 #include "llvm/Instructions.h"
@@ -39,6 +40,12 @@ namespace {
     virtual void getAnalysisUsage(AnalysisUsage &AU) const {
       AU.addRequired<TargetData>();
       AU.setPreservesCFG();
+
+      // This is a cluster of orthogonal Transforms:
+      AU.addPreserved<UnifyFunctionExitNodes>();
+      AU.addPreservedID(PromoteMemoryToRegisterID);
+      AU.addPreservedID(LowerSelectID);
+      AU.addPreservedID(LowerSwitchID);
     }
 
     /// doPassInitialization - For the lower allocations pass, this ensures that

lib/Transforms/Utils/LowerSelect.cpp

@@ -19,6 +19,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/Transforms/Scalar.h"
+#include "llvm/Transforms/Utils/UnifyFunctionExitNodes.h"
 #include "llvm/Function.h"
 #include "llvm/Instructions.h"
 #include "llvm/Pass.h"
@@ -37,7 +38,11 @@ namespace {
     LowerSelect(bool onlyfp = false) : OnlyFP(onlyfp) {}
 
     virtual void getAnalysisUsage(AnalysisUsage &AU) const {
-      // Doesn't really preserve anything.  It can certainly destroy the CFG.
+      // This certainly destroys the CFG.
+      // This is a cluster of orthogonal Transforms:
+      AU.addPreserved<UnifyFunctionExitNodes>();
+      AU.addPreservedID(PromoteMemoryToRegisterID);
+      AU.addPreservedID(LowerSwitchID);
     }
 
     bool runOnFunction(Function &F);

lib/Transforms/Utils/LowerSwitch.cpp

@@ -14,6 +14,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/Transforms/Scalar.h"
+#include "llvm/Transforms/Utils/UnifyFunctionExitNodes.h"
 #include "llvm/Constants.h"
 #include "llvm/Function.h"
 #include "llvm/Instructions.h"
@@ -32,7 +33,15 @@ namespace {
   /// modifies the CFG!
   class LowerSwitch : public FunctionPass {
   public:
-    bool runOnFunction(Function &F);
+    virtual bool runOnFunction(Function &F);
+
+    virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+      // This is a cluster of orthogonal Transforms
+      AU.addPreserved<UnifyFunctionExitNodes>();
+      AU.addPreservedID(PromoteMemoryToRegisterID);
+      AU.addPreservedID(LowerSelectID);
+    }
+
     typedef std::pair<Constant*, BasicBlock*> Case;
     typedef std::vector<Case>::iterator       CaseItr;
   private:

lib/Transforms/Utils/Mem2Reg.cpp

@@ -14,6 +14,7 @@
 
 #include "llvm/Transforms/Scalar.h"
 #include "llvm/Transforms/Utils/PromoteMemToReg.h"
+#include "llvm/Transforms/Utils/UnifyFunctionExitNodes.h"
 #include "llvm/Analysis/Dominators.h"
 #include "llvm/Instructions.h"
 #include "llvm/Function.h"
@@ -37,6 +38,10 @@ namespace {
       AU.addRequired<DominanceFrontier>();
       AU.addRequired<TargetData>();
       AU.setPreservesCFG();
+      // This is a cluster of orthogonal Transforms
+      AU.addPreserved<UnifyFunctionExitNodes>();
+      AU.addPreservedID(LowerSelectID);
+      AU.addPreservedID(LowerSwitchID);
     }
   };
 

lib/Transforms/Utils/UnifyFunctionExitNodes.cpp

@@ -32,6 +32,10 @@ Pass *llvm::createUnifyFunctionExitNodesPass() {
 void UnifyFunctionExitNodes::getAnalysisUsage(AnalysisUsage &AU) const{
   // We preserve the non-critical-edgeness property
   AU.addPreservedID(BreakCriticalEdgesID);
+  // This is a cluster of orthogonal Transforms
+  AU.addPreservedID(PromoteMemoryToRegisterID);
+  AU.addPreservedID(LowerSelectID);
+  AU.addPreservedID(LowerSwitchID);
 }
 
 // UnifyAllExitNodes - Unify all exit nodes of the CFG by creating a new