Re-commit r124462 with fixes. Tail recursion elim will now dup ret into unconditional...

[oota-llvm.git] / lib / Transforms / Scalar / LoopUnswitch.cpp

diff --git a/lib/Transforms/Scalar/LoopUnswitch.cpp b/lib/Transforms/Scalar/LoopUnswitch.cpp
index 009ee7b95eaba6dfca1aeabc78cc82be7e7e0f83..0fc416d67466c6359fec1abb9536c55671ef912d 100644 (file)
--- a/lib/Transforms/Scalar/LoopUnswitch.cpp
+++ b/lib/Transforms/Scalar/LoopUnswitch.cpp
@@ -32,7 +32,6 @@
 #include "llvm/DerivedTypes.h"
 #include "llvm/Function.h"
 #include "llvm/Instructions.h"
-#include "llvm/Analysis/ConstantFolding.h"
 #include "llvm/Analysis/InlineCost.h"
 #include "llvm/Analysis/InstructionSimplify.h"
 #include "llvm/Analysis/LoopInfo.h"
@@ -458,19 +457,6 @@ bool LoopUnswitch::UnswitchIfProfitable(Value *LoopCond, Constant *Val) {
   return true;
 }
 
-// RemapInstruction - Convert the instruction operands from referencing the
-// current values into those specified by VMap.
-//
-static inline void RemapInstruction(Instruction *I,
-                                    ValueToValueMapTy &VMap) {
-  for (unsigned op = 0, E = I->getNumOperands(); op != E; ++op) {
-    Value *Op = I->getOperand(op);
-    ValueToValueMapTy::iterator It = VMap.find(Op);
-    if (It != VMap.end()) Op = It->second;
-    I->setOperand(op, Op);
-  }
-}
-
 /// CloneLoop - Recursively clone the specified loop and all of its children,
 /// mapping the blocks with the specified map.
 static Loop *CloneLoop(Loop *L, Loop *PL, ValueToValueMapTy &VM,
@@ -665,7 +651,7 @@ void LoopUnswitch::UnswitchNontrivialCondition(Value *LIC, Constant *Val,
   for (unsigned i = 0, e = NewBlocks.size(); i != e; ++i)
     for (BasicBlock::iterator I = NewBlocks[i]->begin(),
            E = NewBlocks[i]->end(); I != E; ++I)
-      RemapInstruction(I, VMap);
+      RemapInstruction(I, VMap,RF_NoModuleLevelChanges|RF_IgnoreMissingEntries);
   
   // Rewrite the original preheader to select between versions of the loop.
   BranchInst *OldBR = cast<BranchInst>(loopPreheader->getTerminator());
@@ -969,13 +955,7 @@ void LoopUnswitch::SimplifyCode(std::vector<Instruction*> &Worklist, Loop *L) {
   while (!Worklist.empty()) {
     Instruction *I = Worklist.back();
     Worklist.pop_back();
-    
-    // Simple constant folding.
-    if (Constant *C = ConstantFoldInstruction(I)) {
-      ReplaceUsesOfWith(I, C, Worklist, L, LPM);
-      continue;
-    }
-    
+
     // Simple DCE.
     if (isInstructionTriviallyDead(I)) {
       DEBUG(dbgs() << "Remove dead instruction '" << *I);
@@ -990,15 +970,16 @@ void LoopUnswitch::SimplifyCode(std::vector<Instruction*> &Worklist, Loop *L) {
       ++NumSimplify;
       continue;
     }
-    
+
     // See if instruction simplification can hack this up.  This is common for
     // things like "select false, X, Y" after unswitching made the condition be
     // 'false'.
-    if (Value *V = SimplifyInstruction(I, 0, DT)) {
-      ReplaceUsesOfWith(I, V, Worklist, L, LPM);
-      continue;
-    }
-    
+    if (Value *V = SimplifyInstruction(I, 0, DT))
+      if (LI->replacementPreservesLCSSAForm(I, V)) {
+        ReplaceUsesOfWith(I, V, Worklist, L, LPM);
+        continue;
+      }
+
     // Special case hacks that appear commonly in unswitched code.
     if (BranchInst *BI = dyn_cast<BranchInst>(I)) {
       if (BI->isUnconditional()) {